I Need a Better Backstop

[rsterne]

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….



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

[Gut2Fish]

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.

[Taso1000]

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

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

[rsterne]

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

[PCPhack]

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.

[PCPhack]

We crossed posted. To keep metal noise down on mine, I backed it with sound deadener.

[Taso1000]

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

[Loren]

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

[rsterne]

I have never even seen "rubber mulch" (for gardens? ) and for sure it isn't available in small town BC....

Bob

[PCPhack]

Just offer a hotel discount for anyone that comes up and brings you a bag. Lol. You should have plenty of bags then.

[Loren]

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

[Kinetic45^]

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

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...

[rsterne]

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

[Kinetic45^]

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.

[KnifeMaker]

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???


Knife

[uncle paulie]

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

pv

[rsterne]

You call $25 for 0.8 CCF a good deal?.... 

Bob

[PCPhack]

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? 

I get your point, it may seem expensive for a bag of shredded recycled rubber, but it will basically last forever.

[rsterne]

Yep, it's safety equipment, so in that respect, it's priceless....

Bob

[Back_Roads]

 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