GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Big Bore AirGun Gate => Topic started by: rsterne on December 15, 2018, 05:25:40 PM
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A decade ago I built a target backstop to use when testing my airguns inside my shop, at a distance of 20 feet.... I made a wooden box large enough to accept 12" x 16" pieces of OSB or plywood.... I normally use six layers of OSB, stacked to a depth of 3".... Originally, when I was dealing with low powered guns, I used old magazines, but quickly outgrew that.... Once I started getting into bullet shooting PCPs that were 100 FPE and above, I added a 3/16" steel plate to the back inside of the box, as a precaution.... With the many layers of wood in front of it, I have never had a ricochet.... Bullets impacting the steel flatten on impact, and stay within the box.... Eventually the OSB gets shot up and I have to take the box apart and replace the layers.... This has for the most part, worked great.... BTW, I have three layers of 3/4" plywood that are 32" high and 48" wide behind the box as a safety wall, in case of a miss or penetration of the box.... I feel it's been an adequate and safe setup, although I do inspect it frequently during and after use....
Yesterday I was working on my .457 Hayabusa, which is a 500 FPE gun.... When testing, I often just aim along the barrel of the gun instead of having to install and remove sights all the time, and I'm easily capable of keeping the bullets within about a 3-4" group, centered in the backstop.... Yesterday was no exception, but the OSB was getting torn up badly in the middle, and I was nearly finished shooting, so I didn't bother replacing it.... I kept checking the back of the box, and it was getting pretty big bulge, indicating that the steel plate was bending, something I have seen before.... Every once in a while, after using a particularly powerful PCP, when I strip down the box I pound the steel plate flat with a sledge hammer and reinstall it.... I figured sooner or later it would fail, which is why all the backup plywood and frequent inspections while I am shooting....
I had a few shots more I wanted to take, but I checked the backstop and found a hole in the back, and a bullet stuck in the first layer of plywood, so that was the end of shooting for the day.... When I pulled the box apart today, here is what I found.... The bulge in the steel plate is about 1" high, and you can see the bullet lodged in the plywood above the plate.... both photographed from the back…. :o
(http://i378.photobucket.com/albums/oo221/rsterne/Important/Backstop_zps275tkwl8.jpg) (http://s378.photobucket.com/user/rsterne/media/Important/Backstop_zps275tkwl8.jpg.html)
Anyways, I thought I would share what the power of a modern PCP can do with repeated impacts to a 3/16" steel plate.... You can bet I'm in the process of redesigning my backstop.... First, I will change to a 1/4" steel plate, and secondly I plan to replace the wood with either two layers if 2x4s, one layer in each direction.... or a layer of them on edge.... in front of the steel plate.... The plan is to have them replaceable by pulling them out a slot in the top, so that laziness is no longer an excuse for making sure there is wood in front of the steel.... Additionally, I can remove the shot up 2x4s in the middle of the box and leave the outer ones, which don't see as much damage, instead of replacing 12" x 16" sheets of OSB where the outer portions are still intact.... Once I have built the new backstop, I will post a photo in this thread....
Bob
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I think you should practice on the real thing like Rocky Balboa did. Keep your shop unheated and hang a side of beef to hit.
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I wanted to get one of the 22lr pellet traps for the back yard. So while I was looking for the best price I stumbled on this one on Ebay:
https://www.ebay.com/itm/Bullet-trap-for-use-with-22-thru-44-magnum/292864078081?hash=item44300f3101:g:5uIAAMXQbcRQ74vC:rk:1:pf:0 (https://www.ebay.com/itm/Bullet-trap-for-use-with-22-thru-44-magnum/292864078081?hash=item44300f3101:g:5uIAAMXQbcRQ74vC:rk:1:pf:0)
Overkill? Definitely! Double the price of the 22lr traps. It's rated to .44 magnum and I figure it won't need any maintenance. I am thinking of covering it with Dynamat or something similar so it doesn't ring on bullet impact. An added benefit is that the lead ends up in one spot should I ever want to cast bullets some day.
Mr. Sterne, I know you're handy so maybe you can put something similar together?
Thanks,
Taso
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Metal traps are very loud.... Mine isn't bad because the bullet hits the wood first.... but the wood is sacrificial, just like carpet (or Dynamat) would be.... I don't know anything about that product, or how long it might last....
Besides, my welding skills aren't great.... My trap is scrap lumber and plywood, and a piece of steel plate I hope to scrounge.... very low cost....
Bob
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Bob, why not rebuild it with a 1/4 or greater steel back plate, but angle it, so that much of the initial impact deforms the projectile while also reducing its energy by a lot? Then the secondary backing that they are deflected to would not need changing much. This would work much like the old .22 traps.
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We crossed posted. To keep metal noise down on mine, I backed it with sound deadener.
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I was going to put the Dynamat on the exterior. It's the sheet butyl rubber with a foil backing. It's supposed to change the resonant frequency of automotive sheet metal by adding mass.
I figured the mass of the trap I bought would be quieter than the rattle can 22lr traps. I didn't get a chance to use it this past summer to know for sure.
I don't think my little 90 amp dc arc welder can handle 1/4" steel. I may give it a try next summer and I know it definitely won't be pretty lol
Thanks,
Taso
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Not to persuade you from your plan.
I built a 24" x 24" x 18" plywood box packed it full of rubber mulch. In the back I put two 1/2" thick rubber outdoor patio tiles, and then two 16ga steel sheets for extra measure.
Have shot my .40 Badger at it point black and no indication at back plywood of impact from the exterior. I also have a large plastic tote 24"x18"x18" deep that I filled with just rubber mulch. Shooting the Badger at 50 yards and no pass throughs.
Makes me a believer in using the rubber mulch. Except for your outside target mounting surface the stop is pretty much self healing. The one think I should have done different is put a maintenance hatch on the top vs removing the front face.
Here is an example using a plastic tote and rubber mulch and test results with PB's
https://www.youtube.com/watch?v=F7F9ebfNYDc (https://www.youtube.com/watch?v=F7F9ebfNYDc)
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I have never even seen "rubber mulch" (for gardens? ) and for sure it isn't available in small town BC....
Bob
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Just offer a hotel discount for anyone that comes up and brings you a bag. Lol. You should have plenty of bags then.
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https://www.homedepot.com/p/Vigoro-0-8-cu-ft-Mocha-Brown-Rubber-Mulch-HDVMBMN8CB/203714943 (https://www.homedepot.com/p/Vigoro-0-8-cu-ft-Mocha-Brown-Rubber-Mulch-HDVMBMN8CB/203714943)
Yes for landscaping. I think it may be recycle tire tread. It is really good a absorbing energy.
A cross section of a commercial range bullet trap that uses granulated rubber. Notice they really do not have a really big depth to the rubber.
https://www.range-systems.com/wp-content/uploads/2017/11/Hopper-example-610x584.jpg (https://www.range-systems.com/wp-content/uploads/2017/11/Hopper-example-610x584.jpg)
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Not to persuade you from your plan.
I built a 24" x 24" x 18" plywood box packed it full of rubber mulch. In the back I put two 1/2" thick rubber outdoor patio tiles, and then two 16ga steel sheets for extra measure.
Have shot my .40 Badger at it point black and no indication at back plywood of impact from the exterior. I also have a large plastic tote 24"x18"x18" deep that I filled with just rubber mulch. Shooting the Badger at 50 yards and no pass throughs.
Makes me a believer in using the rubber mulch. Except for your outside target mounting surface the stop is pretty much self healing. The one think I should have done different is put a maintenance hatch on the top vs removing the front face.
Here is an example using a plastic tote and rubber mulch and test results with PB's
https://www.youtube.com/watch?v=F7F9ebfNYDc (https://www.youtube.com/watch?v=F7F9ebfNYDc)
This reminds me of 'Great minds think alike' because I have both a 24x24x24 box with a 10ga steel back and a replaceble front filled with shredded rubber conveyor belt/mulch. AND a cheap $5 20 gallon tub filled with rubber mulch for pellets (wood screws hold the lid down).
The mulch absorbs the energy and then the temporary cavity collapses, resetting for the next shot. Over 300 shots from a 45 Texan and the plate was never even reached... But some rubber mulch was pulverized and it settled some and I had to add 1/2 bag to top it off so there is not a gap at the top.
Note I bought a cheap two wheel dolly to be the skeleton of and build the box on so I can use it inside the garage or wheel it out to the 50 yard point in the back field.
I think 24" deep might be more than is actually needed and it could be shallower but 16" or 18"??? Or? Thing is it's built and I'm not modifying this one but for others...
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Seems expensive.... 0.8 CF bag is $7 and you need 7.5 CF to fill a 24 x 24 x 28" box.... so over $50 US.... Good solution, though, I'll have to keep my eyes open for it next time we're in the "big city".... *LOL*….
Bob
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Seems expensive.... 0.8 CF bag is $7 and you need 7.5 CF to fill a 24 x 24 x 28" box.... so over $50 US.... Good solution, though, I'll have to keep my eyes open for it next time we're in the "big city".... *LOL*….
Bob
But it lasts and lasts and lasts so is worth it in time and trouble and peace of mind. You don't have to replace other materials like boards (always irked me that the center shot out and the corners were still 'good' but you can't shoot the corners, haha).
You do still have to replace the front face though. You can check the fill amount when replacing the front or have a separate door/hatch on top for that.
I just flip mine on it's back of the dolly and unscrew the front nowdays and check/replace as necessary... very infrequently by the way. Check out "Coroplast" for the front, backed by a 1/4" rubber sheet takes a lot of shots before the mulch starts dribbling out the front then duct tape extends the life there.
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I use a 5 gal plastic bucket. (Paint, restaurant oil ect).1/4 steel plate in rear, and a mix of fine and coarse rubber mulch. Stops the .257 and my 1911 .45 just fine.
Been using this system vor over 7 years now. Quiet, inexpensive!
Most hardware stores carry the buckets with lids, and mulch is either in stock, or ordable.
Hi side price for the bucket and lid is 5 bucks or less, 6-7 bucks for mulch. Scrap yard plate. So in for 25 bucks. ;<)
Spare lids apx. 2-2.50 each. They do wear out. LOL
Did I mention very very quiet??? 8)
Knife
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Walmart has a great deal on rubber mulch with free shipping to your neck of the woods!
https://www.walmart.com/ip/INTERNATIONAL-MULCH-COMPANY-NS8ET-8CUFT-Earth-GRND-Cover/38692025 (https://www.walmart.com/ip/INTERNATIONAL-MULCH-COMPANY-NS8ET-8CUFT-Earth-GRND-Cover/38692025)
pv
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You call $25 for 0.8 CCF a good deal?.... ::)
Bob
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Compared to the cost of all our other PCP support equipment, it is really not much, especially considering this would be SAFETY EQUIPMENT. Given the history of safety focus on the board, because Joe Whoever might try something they shouldn't, ought we outline a super safe backstop and not fret over a few 25 dollar bags of rubber to achieve said safety? 8)
I get your point, it may seem expensive for a bag of shredded recycled rubber, but it will basically last forever.
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Yep, it's safety equipment, so in that respect, it's priceless....
Bob
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I find the rubber mulch deals to be seasonal, and while supplies last., get there early when you find a deal.
I have 3 bags of rubber mulch stacked flat in the top freezer section of a decommissioned fridge/freezer. with metal plate behind for security.
https://www.gatewaytoairguns.org/GTA/index.php?action=media;sa=media;in=5779;preview (https://www.gatewaytoairguns.org/GTA/index.php?action=media;sa=media;in=5779;preview)
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I paid $8.48 for 1.25 cuft each on sale and bought 10 bags then got 10% discount for being a veteran at Home Depot so it's not that expensive and that was three years ago and I expect not to dump my first batch in the box for another 4 or 5 years and that's a LOT of shooting! And from that purchase I have three bags in storage for 'make-up' as the mulch gets pulverized and loss.
Shop the internet, the deals are there
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I was doing some cleaning in the shop today and decided the bullet trap needed som attention. The front face has become pretty shot up with several layers of duct tape repair. The face was bulging pretty good so target had a nice arch to them. I reclaimed a 4 quart cast iron dutch oven full of lead. Most of the pellets and bullets where with 6-9 inches from the face, with nothing going deeper than 12 inch and none reaching the rubber tiles or steel at the back. Real pleased with that performance. Tunneling does not seem to be a problem. The lead just starts stacking and begins creating even more of a barrier.
Reclaimed the lead from the mulch by vacumming everything up with the shop vac and then putting batches in a big tub of water. The mulch doesn't really float but I mixed it and got the lead to drop to the bottom. Need a sluice and a mountain stream...lol
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Yep, it's safety equipment, so in that respect, it's priceless....
Bob
Here, Lowes, Home Depot, Wally World, all apx 7 buck a bag. Mike
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Bob, You had indicated you would need to take a trip to get the mulch. Not sure how far in the woods you are but thought the free delivery might be of value.
Edit: Hadn't noticed the size of the trap you had... might be worth the trip? :o :o :o
pv
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Thanks for teaching me about rubber mulch! I just made myself a wooden backstop that's a wooden box with no top, and the front slides out for easy replacement, and I put a big, heavy box of books behind the front. I don't think I'll ever have anything powerful enough to shoot through that. If something were to get through it, there's still plywood behind that that's an actual 3/4" thick. Is that called 1" plywood? It was in my scrap pile.
Another idea I had was treads of used steel-belted tires from the local used-tire store where the owner told me he has to pay to dispose of old tires. I'm not sure I'd really be able to cut them though. Any ideas for that? Would a hacksaw get through them? Obviously tire treads are extremely tough and are supposed to resist being cut if you hit steel shards on the road.
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I have cut up old tires using a coarse metal blade in a sawzall. I does produce alot of smoke.
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I use a 5 gal bucket/lid and just put the whole unopened bag of rubber mulch in the bucket. I cut a big square out of the lid and used an old towel to stretch over the top of the bucket before replacing the lid. This helps keep the mulch from falling out after you shoot up the bag the mulch came in plus it is easily replaced. I ended up putting some old rags on top of the bag of mulch as it was pretty loud with the pellets hitting the plastic bag. Now it is supper quite the only noise is the pellet hitting the paper.
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I too have a bucket and mulch. How are you guys fixing targets to the bucket? I snap the lid out and then fix the paper between the lid and the towel. PITA when changing targets.
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Conveyor belt is good substitute for wood.
Then chains and the second belt and plate.
You should find some company that has changed or changes belts.
Marko
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Since I don't try to have a quiet backstop (I wear earplugs), I just added 3/16 steel plate on top of the existing metal for my 22 rattle trap. Nothing in airguns is going through that. I use some larger sheets behind the whole thing in case of an any accident where I would miss the trap. In this way, I collect the lead for casting, which I hope to get into during 2019. The only downside is splatter, but I have some mass loading vinyl sheet that I put over the opening, or cardboard, which keeps it down. Cardboard is ok for pellets, but with the big bores, the shrapnel itself can splatter back through it.
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Don't count on it, I use old tractor bucket for backstop and its starting to have holes in it from airguns.
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I'm going to try out the bucket and rubber mulch suggestion. Maybe it will stop my big bore? My biggest fear with any trap is ricochets flying back on me. I have had that happen with plywood. Eye protection is best with any traps used.
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I'm going to try out the bucket and rubber mulch suggestion. Maybe it will stop my big bore? My biggest fear with any trap is ricochets flying back on me. I have had that happen with plywood. Eye protection is best with any traps used.
No need to worry about ricochets with the bucket and mulch.
I too have a bucket and mulch. How are you guys fixing targets to the bucket? I snap the lid out and then fix the paper between the lid and the towel. PITA when changing targets.
I cut out the top of the lid and use either a 8”x11.5” piece of construction paper or some cardboard I tape to the lid. I put the targets on the paper or cardboard. Super easy to change targets just tape a new one up. I don’t think I’ll ever have to change the lid unless I hit the edges a ton.
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My HP cast slugs destroy lids. I buy 5 lids at a time. LOL!!!
I place targets directly on lid. I use long deck screws to hold the targets, and the dewalt to install or remove them. ;)
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Well I got all the materials and put together a new backstop today.... The framework is 2x6s with a 3/4" ply back and a 10" x 14" plate of 1/4" steel screwed to that....
(http://i378.photobucket.com/albums/oo221/rsterne/Targets/Backstop%201_zpswprqhxfi.jpg) (http://s378.photobucket.com/user/rsterne/media/Targets/Backstop%201_zpswprqhxfi.jpg.html)
The top and bottom rails, fastened to the front, are 2x4s, arranged in such a way that I can slide three layers of 2x4s in without needing to take out any screws.... The front and back layers are 3 pieces each, vertical, and the middle layer is 4 pieces, horizontal.... which left just over 1/2" of space, into which I slid a piece of OSB.... The target clips are taped to that with duct tape....
(http://i378.photobucket.com/albums/oo221/rsterne/Targets/Backstop%20%202_zpshzhh0dlw.jpg) (http://s378.photobucket.com/user/rsterne/media/Targets/Backstop%20%202_zpshzhh0dlw.jpg.html)
This means there is 5" of wood before anything can hit the steel plate.... Since all the 2x4 filler blocks are separate pieces, I can replace the center ones, which will get destroyed first, and just turn the side pieces over to put the shot sections out against the edges of the opening.... This should be a lot easier and cheaper than replacing full sheets of OSB.... I guess I'll find out soon how it works, but I'm pretty pleased with it, and I should be able to refill it with about half a 2x4 and a small piece of OSB each time, which will be really cheap to do....
Bob
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Interesting...My guess (based on the power you typically push) is that you will blow through the 2X4s within a few shots when in the same hole (Assuming pine boards), but hopefully not.
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I'm typically not concentrating on hitting the same spot every time with this backstop, it's mostly for Chrony work.... While that happened eventually with the 6 sheets of OSB in my previous backstop, if you stack pellets, they tend to add mass and resistance to the travel path, and slow the next (stacked) bullet somewhat.... I guess I'll find out !!!
Bob
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The reason I went with a bigger box for the shredded rubber is I had a side penetration a couple times when first using a 5 gal bucket (with 45 Texan) and shooting four different spots on the target clipped to the lid. I guess if you only shot the center it would not be a problem. Kind of made me leery on big bore use of the buckets but .25 and down I never had a problem
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The reason I went with a bigger box for the shredded rubber is I had a side penetration a couple times when first using a 5 gal bucket (with 45 Texan) and shooting four different spots on the target clipped to the lid. I guess if you only shot the center it would not be a problem. Kind of made me leery on big bore use of the buckets but .25 and down I never had a problem
Yes, that's my concern using the bucket/mulch setup with the Slayer. At only 275-300 FPE, it's probably not quite the power you're pushing with the Texan, but still a concern for chrony work up close. I'm not to worried about it out at 50 yards. One member stated (using a Slayer) he was fine at 3 feet away in his garage. I'll just have to test it out for myself outside first.
At 50 yards, the Slayer has already went through a thick box filled with a mulch and tightly rolled up clothes combination and then through a 3/4 plywood and a 1" thick oak board with just one 5-shot tight group. I want a quiet backstop, but a safe one too for indoor work this winter.
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I shoot into a box of premixed drywall clay and just move the target to 1 of six sides till its really messed up then dig out the lead. I dont care what the fpe is it wont go threw the box. like this Bob https://hardwareonlinestore.com/index.php?option=com_virtuemart&view=productdetails&virtuemart_product_id=5414&virtuemart_category_id=14603&gclid=EAIaIQobChMIoPeu3e6t3wIVDZRpCh1hmQPhEAQYBCABEgIhK_D_BwE
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Looked at tire mulch from HD when I built mine, but here I could only get it in cubic yards, delivered. Seemed a little excessive for my needs ;-)
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I tried out the backstop today with my .457 Hayabusa…. At 500 FPE with a 336 gr. bullet it penetrates about halfway through the wood, so there is plenty of stopping ability there.... It will be interesting to see how much punishment it takes before bullets chew a big hole in the wood and get to the steel plate.... Right now I am spreading the shots out through the Chrony, so it's not an issue, even when they make adjacent holes....
Bob
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I shoot into a box of premixed drywall clay and just move the target to 1 of six sides till its really messed up then dig out the lead. I dont care what the fpe is it wont go threw the box. like this Bob https://hardwareonlinestore.com/index.php?option=com_virtuemart&view=productdetails&virtuemart_product_id=5414&virtuemart_category_id=14603&gclid=EAIaIQobChMIoPeu3e6t3wIVDZRpCh1hmQPhEAQYBCABEgIhK_D_BwE (https://hardwareonlinestore.com/index.php?option=com_virtuemart&view=productdetails&virtuemart_product_id=5414&virtuemart_category_id=14603&gclid=EAIaIQobChMIoPeu3e6t3wIVDZRpCh1hmQPhEAQYBCABEgIhK_D_BwE)
While not finding that exact match locally, it did give me an idea of using some of the moist clay dirt we have around here in a bucket or box. This stuff is quite dense with having very fine granules.
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I'm going to note that I tried multiple materials for backstops down through the years and while many things do work well to stop projectiles what I like best are those that refill the impact cavity which the clays, duct seal or Sheetrock mud, wood blocks, etc tend not to do. That leaves it forming a deeper and deeper hole til it gets all the way through. Yes, you can take the time to repack/re-condense/replace it but I am basically lazy and that was too much work... I read of others success with the rubber mulch and tried it and since it fills itself in on the penetration cavity and had a very very long service life before having to be replaced it won the contest.
The nice thing about all these we are talking about is they are basically silent which even if you are in the country is nicer than the loud clangs of metal targets. I HAVE had a variety of metal backstops, ranging from the 22 Long rifle weight traps to a monstrosity I built with a piece of 3 foot by 7 foot, 3/4 plate that was at a 45 degree angle and the bullets went into a 'snail' trap at the bottom where I collected the lead. (I left it there when I sold the property... too heavy to move!!!).. I used to shoot a LOT of rounds every week, like 300 or 400, 52 weeks a year {some guys would come home and drink a six pac, I would come home and go out back and shoot 50 round of pistol every day and reload something every evening} (EXPENSIVE!!!) and after 6 years the back was starting to bow slightly and I had punched through it with rifle bullets and re-welded the holes multiple times.
Mulch is better for me, nowadays.
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Those are good notes Peter. I think with your experience and input on this, I will focus on the rubber mulch. No need to try and reinvent the wheel. I want to build a box within a box design though so that when the mulch starts falling out of the hole(s) created from repetitive shots, it will fall into the outer box so it can be reclaimed easier instead of having losses on the ground or creating a mess on the floor and having to sweep it up.
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Those are good notes Peter. I think with your experience and input on this, I will focus on the rubber mulch. No need to try and reinvent the wheel. I want to build a box within a box design though so that when the mulch starts falling out of the hole(s) created from repetitive shots, it will fall into the outer box so it can be reclaimed easier instead of having losses on the ground or creating a mess on the floor and having to sweep it up.
I've seen PB videos online (just google it, I shouldn't post a PB video link here) where they used a plastic storage box like the one below from Walmart filled with mulch. It stopped a 9mm, .38 and most various rifle sizes. Check out one of those videos, it makes for a nice big target area.
(https://proxy.duckduckgo.com/iu/?u=https%3A%2F%2Fi5.walmartimages.ca%2Fimages%2FLarge%2F820%2F561%2F820561.jpg%3FodnBound%3D460&f=1)
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Am I the only one that uses sandbags as a backstop?
It's save, cheap and the lead is easy to separate from the sand with a sieve.
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DUH!!!.... That may be the best idea I have heard so far.... ::)
The only drawback is the cleanup of having sand trickle out through the entrance holes.... ???
Bob
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I have thought about using play sand in a double box sorta design too (to catch the spillage). It would fill back in on impact better than the clay dirt idea. Much easier to reclaim the lead too, as I one day want to try my hand at one of Bob's designed molds from NOE. Digging out the lead from the rubber mulch could be more challenging though I do have a DIY sift I might could use.
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The problem I see with sand is that once you get a sizeable hole in the bag / inner sand container, the sand will run out through it, emptying the bag above the hole by gravity.... Shots above that level will go straight through the empty bag / container.... Yes, an outer container would catch the sand, but it could get dangerous for penetration completely through within a few shots....
Sand will, after all, flow through an hourglass.... RATS!!! …. We need a self-sealing container, but I can't imagine one that would stand a lot of shots in the same place....
Bob
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Yes that's true. However, what if the box was tilted so the sand didn't flow out of the holes. Just to be clear, I'm still leaning towards the mulch build lol. I have found some rubber mulch locally for $5.97 per 0.8 cu. ft bag in stock no less. A few bags should do it pending the box/tub build.
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You will still end up with an entry hole, and anything above that can run out, right?....
Bob
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I use sandbags as a backstop for years. The natural corner of sand is 45 degrees, or 1:1, so it will not leak away like water.
I have layed down the bags with a smal angle backwards to prevent that the sand leaks out. After a lot of shooting, I repair the front bag with ducktape. One or two times a year I clean the sand and fill new bags. My sand backstop is aboud 3/4meter thick in 4 layers of bags. It has no problem with slugs out of my Texan 45 on full power.
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You will still end up with an entry hole, and anything above that can run out, right?....
Bob
No, not with the correct tilt, but yes that's too much math to have to deal with when just wanting a no nonsense backstop. The mulch setup must fail before taking the sand approach.
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A sheet of rubber 'on top' of the mulch, behind the lid/face still gets holes but they tend to be smaller and close close up with the round nose stuff and adds 'depth' to the front that lets the mulch bridge the holes.
Then I use a replaceable facing in front of that.
I have one of these outside and one in my garage chrony station
This one will get some duct tape before the next session
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Hatcher's Notebook has some useful data on sandbag and other media penetration. Below is a table for the .30-06 ball round. Note that penetration increases with range in some media. This is due to bullet distortion or yaw at close range in some media.
Pertinent is the distinction between dry and moist sand; and loose earth:
From: https://books.google.com/books?id=yESNUKSg5aMC&lpg=PP1&pg=PA408#v=onepage&q=sand&f=false (https://books.google.com/books?id=yESNUKSg5aMC&lpg=PP1&pg=PA408#v=onepage&q=sand&f=false)
(https://www.gatewaytoairguns.org/GTA/index.php?action=dlattach;topic=152077.0;attach=253177;image)
Am I the only one that uses sandbags as a backstop?
It's save, cheap and the lead is easy to separate from the sand with a sieve.
I was scrolling through the comments to see if anyone mention sand, and you beat me to it. :)
Good old sand bags have been know to be very effective at stopping projectiles, for well over 100 years. They are the low cost alternative to rubber mulch. Even if sand bags are just a back-up to your sacrificial backstop.
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Sand will, after all, flow through an hourglass.... RATS!!! …. We need a self-sealing container, but I can't imagine one that would stand a lot of shots in the same place....
An hour glass only works if the sand is uniform, clean and dry:
Now, water wetted sand is a bad idea for many reasons. However, oil wetted sand; as used to make sand molds for casting metal parts, should stay clumped together much better. Even if you don't used the same oil as for sand molds, I think that 5 liters of used engine oil in 50 liters of sand, would be very effective at making the sand grains just sticky enough to prevent them running out of your trap.
The best oil to sand ratio is something to experiment with on a small scale. Wet, but not so wet that the oil runs under gravity to pool under your trap.
If you could find cheap grease to bond your sand, that may work even better.
Also, make your sandbags small, so that you can easily replace the ones that are torn up.
Ultimately, if you end up with sand heaped up at a 45 degree slope, that you rearrange with a spade every so often, that would not be so bad. Now, indoors, you would want to construct a "sandpit" to contain the sand, and to allow for some "splash".
The above is intended only as food for thought; to break you loose from the hourglass mental model...
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The 30/06 M1 "Ball" round is a 174 gr. pointed bullet at 2630 fps (2675 FPE).... At 600 yards it was still travelling about 1600 fps.... and drops subsonic before reaching 1000 yards.... Somewhere around 950 fps at 1600 yards would be a good guess, I can't find the exact number....
What is interesting is the huge difference between Oak and Sand when supersonic or subsonic.... Compare the penetration at 1600 yards.... It appears to me that sand is great the higher the velocity.... Just an observation....
A "sandpit" isn't going to happen.... too big for indoors, the "splash" would be a non-starter.... but I get your point about dry sand running out through holes easier than wetted with something....
Bob
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Thanks for the chart! Based on that chart, using clay is a very bad idea.
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Other than depth of penetration, clay is not "self healing", unlike rubber mulch. A few shots in the same place on a clay block, and you end up all the way through it...
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Related, I just happened to run across this short video:
https://www.youtube.com/watch?v=h11qtN0-gFY (https://www.youtube.com/watch?v=h11qtN0-gFY)
After the part about the bullet-proof vest, they shoot through boxes of sand to see how far the .50 PB round would get. Not very far.
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It's because of the speed, the bullet gets fragmented.
We measured around 1.5 meters of penetration in to sand back stop with the 20mm, normal rilfe rounds penetrate only some 10-20cm in to the same sand berm.
Energy at the muzzle is just about the same.
Marko
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20mm energy is close to 9.3 x 62 large game rifle round but if we look at the momentum, 20mm is about three times that of 9.3. And yes, bullet stays in one piece.
It is slow but hard to stop.
Though, we haven't see the bullet, should have an excavator to dig it up. ;D
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A note on wetted sand. It varies by sand composition and some sands max out around 13% water by weight before saturating. If you kept it 8% you shouldn't have pooling of water ever. Sands low in fines/dust saturate 7-8%. Oil is 0.8 the weight of water so should be used in equivalent volume.
50 lbs of dry sand will take 2 quarts of water, close enough for 8% moisture, or 2 quarts of oil for equivalent volume.
25Kg to 2 liter.
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Something to keep in mind ...
Silicosis and sand ...
I'll take "heavy metals" over sand any day ...
But, that's just me ... YMMV. ;)
Cheers,
Smoketown
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I think I'm going to go with a long/wide tote that has fairly flat ends with a decent lid latch filled with rubber mulch. It should be at a minimum 29" long or longer from shooting end to shooting end. I plan on screwing in a fitted board to allow a space internally on at least one end if not both so the mulch falling out of the shot board holes will just drop down into the gapped space and not on the floor. A gap big enough that I can duct tape the holes from the outside of it periodically. I am planning on keeping the shot holes at centerline as much as possible and up from the bottom a good bit so this plan works out best.
I do have some steel plates too, but I'll have to make a decision as to whether I'm only shooting at one end of the tote or both. I guess if the tote is long enough, I could place the plates in the middle/center of the mulch. I'd rather have the option of shooting either end for less maintenance.
The whole idea is to stop a 300 FPE slug with fairly tight groups from a rest about 12 feet away indoors. Some testing will be done outdoors at near PBR to be sure this works well prior to indoor use.
P.S. If I can find a tote that fits inside the outer one well enough for gapped space on each end, then I can just move the steel plate from one end to the other easily, which gives me the option of shooting either end of the tote and also less build time.
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Something to keep in mind ...
Silicosis and sand ...
That is another reason why an indoor sand trap should be "damp". To keep the dust formation down. Outdoors, this would be less of a problem; unless you stay close to the backstop and have a breeze blowing at you.
Damp with water indoors = mold. So, no to water. Used engine oil probably has a bunch of nasty stuff in it too that will offgas over time. Cheapest unused oil would be much better.
Most roads point back to rubber mulch...
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Damp with water indoors = mold. So, no to water.
It shouldn't be a problem. We've had an indoor aquarium with the top open for 25 years and definitely don't have any trouble with mold.
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I should mention that with my tub, turned on it's side, where I shoot through the removable lid (which is screwed down to stay down) the 'thickness' is 15 inches.
With my 45 Texan with a TalonTunes bottle filled to 3600 on a regulator'and mounted in a rifle vise where every shot hits exactly the same point and shooting over 45 shots chronying various bullets from 220 gr to 440 gr no bullet penetrated. I used to have a 1/4 steel plate I put in the bottom of the tote before I filled with mulch but no bullet, of any power, reached it when I emptied it to check. I guess you could keep one in for peace of mind or have one behind it separatly. Stuff falling out became almost a non-problem when I started using the sheet of rubber in front of the mulch until the hole gets quite large and as you change targets or just every so often apply some tape.
Note that every so often it helps to flip the tub back on it's bottom to shake the mulch up and resettle it to collapse any cavities that have formed... Like 70 or 80 shots of big bore. If you were shooting through the side (?) I guess you could just 'rock it back n forth' hard a couple of times to do the same thing.
I used a huge tub at first that filled with mulch was too heavy to move but changed to this smaller one that although it is heavy I can pick up and walk with. It's 20 x 16 and 15 inch deep mulch
So it's a couple of hours later and meanwhile I went out and emptied the mulch from the tub an inch at a time to see the depth and record them. The tub had been emptied last month so this is just a few sessions of shooting. Also, I put the tub on a scale first and it weighed 141 pounds with the slugs in it.
First I came to pellets of .22 and.25 shot from a Chief and a Marauder and 90% were in the 2 to 3" zone
then I got down to the 5 - 6" depth and you can see what I recovered by the picture labels
there were a couple of bullet going down but deeper scattered in but most of these were around 8" then it thinned out again
Until I got to about 9 to 10" deep and encountered another 'layer'
I found nothing else until I got to the 14 inch deep and found the solid .457, 362gr launched at 4500 PSI out of my Texan at point blank and over 900 FPS
You can see that the different depth probably correspond to the FPE of the slug.
It is true that the last slugs (457) were just an inch from penetrating but really they are a special circumstance and if I was shooting these a lot I would put the steel plate back in the bottom of the tub. But since MOST of the .357 and .457 had stopped earlier and had a lot of mulch left to travel through I feel safe for regular pellet rifles and regular big bores. There are several .457 I recovered in the 8 to 9" layer that were shot at 3000 PSI with a regular valve, not the Doug Noble high pressure one that drove the others so deep. I also note that although you can see some bullets that struck other bullets they tended to spread out in a 'pancake' of about 5" even though they all were shot into the same 1 inch on the face of the tub so I plan to never shoot closer than 6" from the side to prevent a bullet from veering and punching out the side. It would still hit the wall right beside the tub but I still don't want that, haha. to see a larger picture of my rifle vise, chrony and backstop I have one at https://www.gatewaytoairguns.org/GTA/index.php?topic=152105.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=152105.0) , post #18
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Thanks Carl that helps a lot! I would like to keep the weight down and not go overboard there.
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I have approximately 2 feet thick of rubber conveyor material backed by a 1/2" thick AR500 steel plate. I have shot my 45-70 Gov't into the backstop in my basement!
Most powder burning projectiles penetrate less than 6". I rotate the conveyor material every month.
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I can imagine some lower powered airgun projectiles bouncing off solid conveyor belt, returning to sender. Also, the belt will become "holy" when hit multiples times in the same location. The beauty of rubber mulch is that it has almost no bulk strength, and so collapses in on holes punched by projectiles.
In any event, rubber acts like a super viscous fluid that is extremely "lossy" to projectiles. Its particular combination of mass and stickiness seems to work very well. This, while rubber is much less dense than the projectiles, so screening out the lead later is easy.
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Bob, your original design looks pretty useful. You have built it so that you can replace the sacrificial wood.
If you have a slot on the left and right sides then you could cut the plywood longer than the trap. Even the full width of the plywood, in the USA it's 48 inches (about 1,2 meters).
Then periodically slide the sacrificial plywood left or right.
If you place the bullseye a few inches above the center then you can flip the sacrificial plywood over and run it back through.
When it has a lot of holes then just make a trellis for garden vines.
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My outside traps are a foot by a foot mouth, with the top plate angled 30-degres downwards. They rest on a bin of sand. Dry. the wet stuff can hold a hole, and that is not so good. The plate is 12 ga/.106" mild steel. They are not for indoor use, as there is a lot of splash, and a wee bit of dust as the mostly spent lead hits the sand.
Inspiration taken from reading about the sloped armor on Panthers...:)
cheers,
Douglas
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Angled metal deflectors have their place (had multiple ones) but are usually not backyard friendly...
Most of us do so much to have a quiet gun but the CLANG of pellets or especially slugs hitting that backstop gong sure alerts the neighbors SOMETHING is going on!
That's why I switched to soft targets.
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I finished my indoor backstop project today. I repurposed two heavy duty Brute totes that I used for raising worms. They are 15" deep and one is stuffed to the rim with shredded rubber mulch. Boy is it heavy at around 125lbs, guessing. That's four 0.8cf bags of shredded rubber mulch in there.
(https://i.ibb.co/KF8Kprk/Pellet-trap-01.jpg)
On the second tote/bid, I hot glued a 1/4" steel plate into the bottom, and the rubber filled tote can slide in and out of it to reduce weight when moving if need be.
(https://i.ibb.co/99Zm1kL/Pellet-trap-02.jpg)
I packed the mulch in using a sledge hammer and then secured the lid with screws. I also marked where the steel plate lines up, and where the actual bottom aligns due to there being a narrower bottom than the top portion. Now I know where best to put the target to align with the steel plates, and not shoot out the slanted sides/ends.
(https://i.ibb.co/DfW2r6y/Pellet-trap-03.jpg)
I also repurposed an old table saw stand that has wheels on it so I can slide this contraption in place for gun tuning and shooting, and then out the way in the tight quarters of my man hut.
(https://i.ibb.co/2gFTnNW/Pellet-trap-04.jpg)
The final setup looks good to me and is ready for any kind of shooting and tuning I want to do this winter. The hut is heated with a propane heater. The shooting angle is also aligned with a large cedar tree trunk if all else fails.
(https://i.ibb.co/1XQyPvn/Pellet-trap-05.jpg)
I have no plans of hauling this heavy contraption out to my 50 yard range due to its weight, but do have a dolly, so maybe to capture the lead for future cast. My immediate plan is to move a few of these cut logs I have nearby in place for the 50 yard range backstop.
(https://i.ibb.co/P9yVwcB/Pellet-trap-06.jpg)
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Great set up there Keith.
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Great set up there Keith.
Thanks Jerry! Nothing special, but hopefully it will stop the Slayer. I had to work the garden today before the approaching hard freeze. I'll be testing it out soon to see if it will.
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Looks great, Keith. That should do the trick.
I was lucky enough to have an old wood stove to repurpose as a basement pellet trap. But, even with that, I added a 45 degree barrier of old cast iron window weights. Plus allot of "stuffing" to keep the noise down. Someday, I need to do the separation to reclaim the lead. It's not very portable, though. ;)
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Looks great, Keith. That should do the trick.
I was lucky enough to have an old wood stove to repurpose as a basement pellet trap. But, even with that, I added a 45 degree barrier of old cast iron window weights. Plus allot of "stuffing" to keep the noise down. Someday, I need to do the separation to reclaim the lead. It's not very portable, though. ;)
Thanks John! I did have a smaller box of shredded rubber mulch I have been using. I put that mulch in one of the new mulch bags to sort the lead out of it later. I did try to sift the lead some and only got one tin full so far, but it was a tedious task for sure. The old mulch turned into much smaller pieces, many smaller than the pellets, but not all of it. I also had rolled up cloth mixed in there, that was a mistake as it got shredded within the mulch. Wished lead was magnetic, LOL. At least as far as being able to sort it from the rubber that is.
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I think most of my pulverized stuffing will float and would try a water separation method. Some would end up with the lead, but probably burn off in the first melt down stage. Not sure what rubber particles would do but suspect some dark arid smoke. Probably allot more trouble than its worth.
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I think most of my pulverized stuffing will float and would try a water separation method. Some would end up with the lead, but probably burn off in the first melt down stage. Not sure what rubber particles would do but suspect some dark arid smoke. Probably allot more trouble than its worth.
Great tip! I'll have to give that a whirl ;)
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I reclaimed this from my trap using a water separation method. It takes a pretty good size tub. Some of the rubber floats some, but most is kind of in a slurry. At least the lead drops to the bottom and when stirred the rubber goes into suspension.
It created a lot of black smoke when smelting, and the rubber burning adds to the heat to get the lead melted. After I could tell the lead was melted I snuffed the rubber fire with the lid. Had a bunch of rubber charcoal on top and just dumped it off. I must do outside kind of operation. ;D
(https://i.imgur.com/9jwCezk.jpg?1)
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I am a long ways from doing any casting, but it does seem to interest me, so maybe in the future. I haven't even sorted out the NSA slugs in my big bore yet. These are good tips though that I'm taking notes on for sure, and am thankful for. At least I got a backstop now to collect lead if I ever do some casting.
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To date, my casting is for underwater hunting. :)
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Putting the lid on really helps. The remaining cloth if any, and mulch will act as a reducer, and cleaner, and flux the lead well. ;)
Knife
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I tested my new indoor rubber mulch backstop today with the .357 Slayer. Looks like it will work! The distance from the muzzle to the backstop face was 6 feet exactly. The nine shot grouping was somewhat tight, but not a single hole.
(https://i.ibb.co/N1yj5j1/Backstop-test-01.jpg)
I took the lid off and carefully dug down to see just how far the 142gr NSA slugs went in with the nine shot string I ran. The measurements as a dug down were as follows:
- 7.75"
- 8"
- 8.25"
- 8.5
- 5-9 were at 9.25"
The total depth of the rubber mulch is 15" so I had plenty of room to spare plus the 1/4" steel plate in the second tote/bin.
(https://i.ibb.co/Xj9S0m8/Backstop-test-02.jpg)
The back of the lid took a good hit. I should have put some duct tape on the backside to prevent such a chunk being removed.
(https://i.ibb.co/0KKmz36/Backstop-test-03.jpg)
I did put some heavy-duty duct tape on the backside before reassemble to help out the plastic in the future.
(https://i.ibb.co/JBMmNvj/Backstop-test-04.jpg)
This is what the slugs looked like after retrieving them.
(https://i.ibb.co/R9B82Rc/Backstop-test-05.jpg)
Here is the nine shot string showing the energy applied.
(https://i.ibb.co/KXk6gt1/2nd-Slayer-string-01.png)
Here is the string without the first stiction shot and only viewing six of the shots, which the gun was built around (6 shots averaging 275 FPE).
(https://i.ibb.co/yP2N7M4/2nd-Slayer-string-02.png)
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Hey, Keith.... first time I have seen a shot string on the Slayer.... If you back the power down a bit can you get an actual bell-curve?.... Without the first (stiction) shot, as you indicate, it is 2 equal shots and then a decline.... While that is a great tune for a big bore, I'm curious if a bell-curve is possible.... Still, 5 shots within a 3.5% ES is nothing to be sneezed at.... 8)
Bob
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Hey, Keith.... first time I have seen a shot string on the Slayer.... If you back the power down a bit can you get an actual bell-curve?.... Without the first (stiction) shot, as you indicate, it is 2 equal shots and then a decline.... While that is a great tune for a big bore, I'm curious if a bell-curve is possible.... Still, 5 shots within a 3.5% ES is nothing to be sneezed at.... 8)
Bob
Yes it will on a 3600 psi fill. I tried the max fill today at 3800 just to see. I posted my first string filled to 3600 psi over on the .357 Slayer thread. I'm not sure what that first shot was about. I know the gun has been sitting for a while and was cold plus the extra fill pressure.
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Ahhhhhhh… if you were over the pressure it was tuned for, the first shot would be low, as you experienced.... Makes sense.... Likely NOT a stiction issue, just partial valve lock from the 3800 psi....
Bob
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Ahhhhhhh… if you were over the pressure it was tuned for, the first shot would be low, as you experienced.... Makes sense.... Likely NOT a stiction issue, just partial valve lock from the 3800 psi....
Bob
It's an awesome gun, but I just got it, so still getting it sorted out. I don't know if you found the other thread, but it's very accurate, that I have figured out already.
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FYI, the pellet/slug trap I built works fantastic (reply #76)! It has stopped all slugs I have shot at it with my Slayer, much of which are only a couple of feet away from it, and typically near 300 FPE or more. Never once has a slug poked through the back of the mulch and into my backup safety steel plates in the second tote.
I don't have to move the second tote with the steel plates when relocating this outdoors, which makes it much lighter to deal with. I still do need a dolly to move it though, which is easy to move that way. I use a hoist chain setup to raise and lower it on the table you see in the picture. Very easy that way. One day I'll reclaim the lead from it when dipping low on lead for casting. I use it for all of my guns. Works great for me and is a silent trap, which I like.
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I've enjoyed the rubber mulch traps for years.However, I got tired of the hours it took to reclaim the lead. Some are lucky I guess. I find that a great deal of the mulch sinks in water. PITA!!!
This is why I switched to real purpose built bullet traps. I simply pour the lead out. Easy, Peasy!
Knife