GTA
All Springer/NP/PCP Air Gun Discussion General => PCP/CO2/HPA Air Gun Gates "The Darkside" => Topic started by: AndyKunz on August 21, 2020, 04:05:10 PM
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Let me preface this by saying I love my 1085. I changed it to a nice wood stock (from a QB78 Deluxe), found a way to use Marauder magazines in it, found a great 3D printed flexible single tray, and see lots of applicable QB78 information online (much of it right here in GTA, in a book by an unmentionable author, and on several other forums around the globe). I've worked with Caption O-ring to get a bill of materials together for a 1085 rebuild kit. It has been a lot of fun.
A few weeks ago I started having a problem with the one CO2 cartridge not puncturing every time. Now it doesn't puncture at all. The other one punctures as I tighten the cap.
This thread is not a rant. I've almost exhausted my options, and wondering if there is something to add to my to-do list. Here's what I've tried so far:
* I put a dime (or two) between cartridges.
* I opened the cap 1/4 turn (this is important on my Umarex Ruger 1022, no noticeable difference here)
* I have removed half of the felt, in case it was a cause.
* I polished everything that slides (except the piercing pin itself)
Yesterday I spent several hours polishing everything that moves in the gun except inside the trigger mechanism. The smoothness now is an amazing improvement, something I should have done before the first shot. If there was any possibility that the hammer was hanging up, it's not true any more. I didn't touch the pin yet, though.
I have not:
* Changed from Crosman CO2 (I have another 120 to go ...)
* Ruled out going bulk fill. I prefer not to.
* Called Mike about working on it.
Things to try tonight:
* Put the full felt back in.
* Polish the piercing pin.
* See if I can find some non-Crosman CO2 (Looking for suggestions for IN STOCK and KNOWN-GOOD)
Helpful threads:
* https://www.gatewaytoairguns.org/GTA/index.php?topic=91832.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=91832.0)
* https://www.gatewaytoairguns.org/GTA/index.php?topic=137730.0 (https://www.gatewaytoairguns.org/GTA/index.php?topic=137730.0)
* https://www.gatewaytoairguns.org/GTA/index.php?topic=114228.20 (https://www.gatewaytoairguns.org/GTA/index.php?topic=114228.20)
Any other links I should review? Any more suggestions for things to try?
Andy
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It's sealing...so can only assume the piercing pin isn't piercing. Would be interresting to know if the bottom 12gr. NEVER gets popped or if it will pop if you loaded a full one and then an empty.
Could be from several things, which you aren't going to solve from the outside.
If it's been way- low-tuned, could be not enough energy to pop the 12gr.
The piercing pin could be dulled...but it would need to be pretty dull (ever load the first one backwards?).
Possible to have it seal and NOT have the front half of the valve screwed down tight...which would make for a real long reach for the piercing pin.
Could be some kind of hang-up inside the valve itself.
Could have removed more than just the fiber filter. That washer/spacer with a hole in it does seem to help center the piercing pin.
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It's sealing...so can only assume the piercing pin isn't piercing. Would be interresting to know if the bottom 12gr. NEVER gets popped or if it will pop if you loaded a full one and then an empty.
I tried putting in a new one first followed by an empty one. It doesn't pop it.
If it's been way- low-tuned, could be not enough energy to pop the 12gr.
It worked for a month. I've lost track of rounds, but certainly close to 1000 if not more. And getting 100+ shots from a good set of cartridges, that would be 10 times it punctured OK.
The piercing pin could be dulled...but it would need to be pretty dull (ever load the first one backwards?).
No. And I'd deserve it if I had! There's a pretty good dimple in the end, just not enough to open it up. When this problem first arose, I would continue to shoot to drain down the cartridge, but that was getting ridiculous as so little CO2 came out each shot. That wouldn't be too different than inserting an empty and a full to see what happens, so I'm saying it won't matter.
I hate how using pliers is damaging the cap finish :(
Possible to have it seal and NOT have the front half of the valve screwed down tight...which would make for a real long reach for the piercing pin.
The front of the valve is screwed down tight. In order to get the rear O-ring to go into the tube, I have to not compress it. Then it slides into place with a little help of a push rod. I then tighten up from the front as advised in Steve A's book.
But your comment gave me an idea. I'm going to insert two empties and see how far the cap closes to, and compare that to what I get with a new set of CO2.
Could be some kind of hang-up inside the valve itself.
Could have removed more than just the fiber filter. That washer/spacer with a hole in it does seem to help center the piercing pin.
The washer is still in there, and if I push the valve manually from the rear it opens without jamming. I can push the hammer right up to the limiter.
Good thing to check: Does the stroke match the necessary depth to puncture?
Thanks for the questions!
Andy
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I have not:
* Changed from Crosman CO2 (I have another 120 to go ...)
Next Wednesday I'll have 100 Umarex cartridges here to try. I used Umarex once before, but not since I got this gun. They won't go to waste even if they don't work here. :)
Andy
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It could be the 12 gr cartridges, with like Crosman, one sometimes has to put a dime / penny in between the carts to get a full pierce.
I have that issue with one of mine , and was in the process of using one cart on one end then the other to see what one was the issue, then got sidetracked ::)
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It could be the 12 gr cartridges, with like Crosman, one sometimes has to put a dime / penny in between the carts to get a full pierce.
I have that issue with one of mine , and was in the process of using one cart on one end then the other to see what one was the issue, then got sidetracked ::)
Already tried with dimes. No luck.
Tonight I tore it down again and polished the puncture pin sides, the tip, and the hole it slides through. While I had it apart I also took some measurements and photographs. Maybe one of these will suggest something to somebody...
Picture 1 shows two Crosman cans from yesterday. The one on the left is the second one (inserted second, "front", etc) and the right is the one that goes in first. You can see a dimple, and the dimple is pretty well centered (not always the case).
Picture 2 shows a close-up to compare the ends of two types I have on hand, a Daisy and a Crosman. Picture 3 shows the labels just to be sure.
I showed you all those so, if you'd be so kind, you could compare to what you have that works.
Picture 4 shows the depth that the puncture tip goes into the end of the can. It really is right about 1mm more that it could travel before the blunt faces hit, which I'm sure would give a good hole.
Picture 5 shows what the tip looked like before I started tonight. I have since polished it up. I don't think it did much other than to make it shiny, but shiny is nice too. :)
Picture 6 is something I hadn't noticed earlier. The spring inside the valve has both ends flattened. It looks to me like they were ground provide an even pressure between the pin and the valve pin, probably to prevent sidewards motion (and thereby jamming).
Picture 7 is the length of the pin, 29mm. If anybody has one of these and could compare, I'd appreciate that.
Picture 8 is the valve spring, 20.7mm. Again, if you have one to compare, that would be great.
Picture 9 is the main spring for the hammer, 59.5mm. I'm wondering if this isn't providing a hard enough whack.
Next time I have it apart (gotta do some yard work tomorrow, so probably not until after church on Sunday), I will weigh the various parts. It just dawned on me that that might help generate some discussions.
So, recap on tonight:
* The Daisy can didn't work any better. I used 1 Daisy, 1 Crosman (because the Crosmans work fine at the other end).
* The polishing on the pin and guide hole didn't help. Hopefully all the polishing that happened to the air path will help down the road.
* I measured the over-travel of the hammer between rest position and full-forward (which would puncture) at 3mm. The tip is right at 2.5mm, so it SHOULD be hitting the can right up to its face. That was why I measured the hammer spring, in case that's not the right length.
* I also cranked the end cap all the way down, using pliers. I'm going to need a new QB78 new-style (long) cap once I get this figured out... :(
I appreciate all the views you are all making. If you have any ideas at all, please comment! I'm a firmware engineer by trade, and my team has been tracking down a problem that was reported several months ago. One of the guys managing the project mentioned that somebody made an offhand comment about something he did that caused it to work, and that offhand comment gave us the solution we needed in about an hour of brainstorming. Every little idea counts! Your "my ideas never work" thoughts might be the solution for me! Please share!
Thanks.
Andy
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Made me look.
Taking mine apart,the striker spring is just about the same length as that,and it seems to work for poping both 12gr. with the first try. Am a little suspicious of the open end of the striker you show spring....usually they have a closed/dead end....so that one does look like it's been shortened....but the factory has done that kind of happy-whappy stuff before.
So am thining something elese is going on....but if spacing the spring to add tension to the striker spring works,may as well try it and see.
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Sounds like something is keeping the piercing pin from hitting correctly. Compare your valve parts to online pictures, like ones at 4rcher$.
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Does look the same...it's your basic QB valve, pretty much the same valve in the WB78,79 used in the 1085.
Don't know about the valve stem retrun spring you show...haven't measure that on mineand the only other loose QB valve has been modded.
Just to be sure about operation.
Will call the first one loaded in (neck down) as #1 and the 2nd one the one loaded last (neck up).
IF you charge it the way directed, would tighten down the end cap...hear a little hiss from #2....and back the end cap off a fraction of a turn and hear #2 fill the tube.
Then we cock and fire to pop open #1.
#1never gets a full power piercing pin strike that way....valve stem is working against the pressure created by #2. The valve movement is a whole lot less that your picture of the pin protuding when it's being held closed by co2 pressure...and in this weather,that can be a lot of pressure.
Little quick math....valve stem seal body is about .37"...works out to about .107 square inches.....so if #2 supplied 1000psi, would be 107 pounds of force holding the vlave closed BEFORE we try and pop #1.
Usualy it will pop a little hole in #1.
We don't notice #1 starts with a tiny hole,becasue we don't open it up to look until the gun is empty enough to need recharging. By that time,it's beaten the hole in #1larger though reptition and lower pressuresas the gas runs down.
So....just to be sure...if you load a live #1 and a dead #2, if it doesn't pop open #1 (at least a little), then you for sure have an issue with striker spring tension or some kind of power robbing blockage/friction inside the valve.
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Your explanation matches my understanding as well.
I haven't tried loading a dead #2 yet. That's an easy thing to try.
I need a break right now (backfilling behind retaining walls), so I tried it.
HEY, THAT WORKED. Sounds like we're onto something here! I'm gonna get rid of a few pellets and see how long this lasts.
Andy
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So it did pop the canister open, but it doesn't have any power behind it even after 2 dozen shots.
I have to get back to work outside now. I'll take it apart when I'm done.
Either the hole it's making is insufficient, or there is something about the valve that needs fixing. Maybe the felt is too much resistance? Or it's not opening all the way? I don't know, but at least now I have something more to go on.
Thanks for your help!
Andy
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Can you post a puncture picture of the last cart you used with low 2 doz. shots.
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Can you post a puncture picture of the last cart you used with low 2 doz. shots.
Wow, Leo, you knew just the question to ask!
Here you go. The hole isn't a hole, it's better to think of it as a minor leak :) It actually doesn't open like a hole, it's really just a crack in the dent. I tried a #79 drill bit (smallest I had) and it doesn't even detect a place it wants to go. Looking at it under a magnifier, it really is just a crack.
If these aren't good enough, let me know. I'll try setting up a more formal photo.
Andy
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IF that is #1 with a dead #2...then you either need a bit more striker spring tension or a less strong striker return spring....or just not worry about it.
Could load a live #1and #2,screw the end cap down, and quickly fire to pop open #1 BEFORE you back the end cap off that fraction of a turn.
Seriously...the only co2 a 12gr. running rifle gets to shoot from is whatever co2 is already in the valve....any "refill" of the valve doesn't get there quick enough to make a real difference.
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That poke right there should give you power shots. One way you won't get the desired power is if your TP is restricted. Remember when you showed your oem TP being crushed and replaced it with poly tubing. You cut that too short it leaks and cut it too long and it get crushed.
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There is some weird math to QB's double 12gr.system.
Using one 12gr.,lets say it takes 2 grams of co2 to gas up the tube and the empty 2nd 12gr....leaving 10-10.5 grams of liquid co2 to shoot from.
Popopen two 12gr,and it may only take 1gram of co2 to fill up the tube (beacuse the 2nd 12gr. is not an empty one)...so you have 23grams of co2 to shoot from.
So there is always more than 2X as many good shots from 2X12 than there is with 1X12grams.
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IF that is #1 with a dead #2...then you either need a bit more striker spring tension or a less strong striker return spring....or just not worry about it.
Could load a live #1and #2,screw the end cap down, and quickly fire to pop open #1 BEFORE you back the end cap off that fraction of a turn.
Already tried that. Didn't change anything.
Seriously...the only co2 a 12gr. running rifle gets to shoot from is whatever co2 is already in the valve....any "refill" of the valve doesn't get there quick enough to make a real difference.
While reading up on this last night, I saw a number of valve mods intended to increase the refill speed of the valve.
The first shot is good. I easily hit my target at 40 yards. The second and following shots drop 2' on the way to a 20 yard target. Even if I wait a minute or two, or only 10 seconds, same result.
Andy
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That poke right there should give you power shots. One way you won't get the desired power is if your TP is restricted. Remember when you showed your oem TP being crushed and replaced it with poly tubing. You cut that too short it leaks and cut it too long and it get crushed.
I've just been eyeballing that, but I suppose I can measure with a depth gauge and go from there. Got a suggestion on how much it should be compressed?
But as I just noted, I DO get a good shot at full speed. Just one. And then after that one, they're better described as farts than shots coming out of the barrel, whether I wait seconds or minutes between shots. It would seem to me that they would stay full speed. I can see that maybe subsequent shots slightly slower due to contraction from the cold, but after warming up in the sun for a minute on a hot day, you'd think it would be back to size pre-first-shot again. But that isn't happening.
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I do have valve lock issues with one of my QBs when temps get above 85 degrees, I'm thinking more hammer spring to cure that.
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Quick question:
The 1085 is a cock-on-open setup (which as I understand is like "the XP mod").
Is there a different order to the way the hammer and springs, etc. go into the tube vs. a QB78? Got a picture showing the correct sequence and orientation? I had a dream last night that I was putting the gun together backwards. I never consciously tried putting it together a different way, so it's entirely possible I have it backwards, if it's possible to put it together backwards. I haven't taken it down since yesterday, and probably won't until tomorrow as today will be grape harvest in my back yard.
Andy
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I do have valve lock issues with one of my QBs when temps get above 85 degrees, I'm thinking more hammer spring to cure that.
The gun is usually in my air conditioned (73F) shop, at least until the first shot is fired. It wasn't all that warm yesterday, only about 82.
I'll take a few shots before work tomorrow, as it'll be mid-60s. Thanks for the suggestion.
Andy
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Good news is that the 1085 will let you pull most the striker parts out without having to take the breech off.
(Pasrts 3/4/spring comes out...striker stays in).
(https://live.staticflickr.com/65535/50116648232_9ce840c6d4_w.jpg) (https://flic.kr/p/2jmCVtW)DSCN2834 (https://flic.kr/p/2jmCVtW) by Robert Dean (https://www.flickr.com/photos/144930793@N07/), on Flickr
Can't see any difference in the plastic spacer (#3) used that can go in either way.
There is an unused hole at #4 simply becasue it's a QB part and they already had a hole.
The spring could go in either way.
Thy used a standard QB78 striker,but added a threaded rear hole for the threaded cocking pin (#5). It's the only hole that's threaded,so never tried it in the non-threaded one.
Normal QB has part #4 using a pin....so you have to take the breech off to get to the striker spring if shimming the spring is on your mind. This one,can just undo the rar action screw and pull out #3 and 4 leaving everything else in place.
Yeah...are mods to increase the gas flow tinto the valve. I'm not much for hot rodding Co2's anymore,but that's one step.
Becasue of the way the reciever covers so much of the tube, a transfer port leak is a lot harder to detect....always worht a tesst,but the escaping gas spreads out over such a wide area it's not as obvious with the 1085.
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I had a similar problem. with my QB78. So I'll skip th the punch line. The valve stem...the steel stem in the brass had pushed to the rear a bit. This effectively shortened the striker stroke to the point that it didn't have enough hit to do the job.
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Different ends of the system....the valve stem poppet is just fine....the substitute 12gr.seal is a little stiff for the ProTop and needs to be a little more "finger-screw squishy".
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Can't see any difference in the plastic spacer (#3) used that can go in either way.
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OK, so I'm putting it together correctly.
Becasue of the way the reciever covers so much of the tube, a transfer port leak is a lot harder to detect....always worht a tesst,but the escaping gas spreads out over such a wide area it's not as obvious with the 1085.
I'm going to work on that angle first, since it's easy enough to do. I picked up larger tubing at the hw store this morning to see if that fits the diameter better.
One of the mods I saw was to recess the transfer port area on both sides to provide a positive well for the seal to center on and be retained within. Now I need to find a friend with a Bridgeport :)
I had a similar problem. with my QB78. So I'll skip th the punch line. The valve stem...the steel stem in the brass had pushed to the rear a bit. This effectively shortened the striker stroke to the point that it didn't have enough hit to do the job.
Mine has a steel rod end-to-end, and the end of the steel is flush with the end of the brass.
Andy
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I measured the depth at 1.6mm, so I made a new seal cut to 2.0mm. I opened the seal up slightly with a drill bit to remove some material from the inside, then pulled it over a 7/32" bit and warmed it with a heat gun to help it like the new size better.
The photo shows how it fits.
While I was taking it apart this time, I noticed a slight hang-up with the cocking pin against the side of the slot. Upon examination I noticed that there was a slight burr, so I polished it off.
The Umarex CO2 came yesterday, so I used two of them for my tests. It was about 87 degrees outside, but the gun was about 72 from being inside my office all day. I got off one or two good shots, but then the next 8 fell short. Like, 2' drop in 20 yards. I can shoot spitballs harder.
I didn't have time to continue testing, as I had to get out in the yard and get some raking and grading done where I had a piled up for two years. A farmer came today and carried off 5 tons of fill for me. Whew!
So this morning I take it outside, still with yesterday's CO2 in it. It's about 69 in my office and outside. (It's a little more humid outside!) I'm shooting at my 40 yard target - for a first shot I just aim at the middle of my burn barrel, and it hits about 1/2" off my point of aim. OK, that's fine, I had that happen a few times in the past with the first shot. So I take another. Same thing. 10 pellets later, I'm still hitting my point of aim, and it's hitting it hard.
The improved port seal can't be hurting anything, and the polishing may have been a factor. Maybe this temperature thing is a problem for this gun. I'll find out this afternoon when it gets into the 90s.
Thanks again for all the suggestions! What a great bunch of guys you all are.
Andy
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I measured the depth at 1.6mm, so I made a new seal cut to 2.0mm. I opened the seal up slightly with a drill bit to remove some material from the inside, then pulled it over a 7/32" bit and warmed it with a heat gun to help it like the new size better.
The photo shows how it fits.
While I was taking it apart this time, I noticed a slight hang-up with the cocking pin against the side of the slot. Upon examination I noticed that there was a slight burr, so I polished it off.
The Umarex CO2 came yesterday, so I used two of them for my tests. It was about 87 degrees outside, but the gun was about 72 from being inside my office all day. I got off one or two good shots, but then the next 8 fell short. Like, 2' drop in 20 yards. I can shoot spitballs harder.
I didn't have time to continue testing, as I had to get out in the yard and get some raking and grading done where I had a piled up for two years. A farmer came today and carried off 5 tons of fill for me. Whew!
So this morning I take it outside, still with yesterday's CO2 in it. It's about 69 in my office and outside. (It's a little more humid outside!) I'm shooting at my 40 yard target - for a first shot I just aim at the middle of my burn barrel, and it hits about 1/2" off my point of aim. OK, that's fine, I had that happen a few times in the past with the first shot. So I take another. Same thing. 10 pellets later, I'm still hitting my point of aim, and it's hitting it hard.
The improved port seal can't be hurting anything, and the polishing may have been a factor. Maybe this temperature thing is a problem for this gun. I'll find out this afternoon when it gets into the 90s.
Thanks again for all the suggestions! What a great bunch of guys you all are.
Andy
Have you checked the stem as I mentioned.. These guns have had this problem for yr's. Without full stroke it will never work correctly.
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Have you checked the stem as I mentioned.. These guns have had this problem for yr's. Without full stroke it will never work correctly.
Yes, I addressed that at the bottom of my previous reply:
Mine has a steel rod end-to-end, and the end of the steel is flush with the end of the brass.
I would add, there is no deformation of the brass to suggest that it was expanded as the steel rod pushed its way through. And there was no burr on the outside end of the steel where the hammer hits it to suggest it had been shortened by repeated blows. The diameter of the impact faces appears to be the same at each end of the rod.
Andy
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Sorry Andy, I must have missed your earlier reply
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No problem!
If I ever have to open it up again, I'll measure how long the valve/actuator assembly is. I didn't do that previously because I didn't see any wear/damage, but it wouldn't hurt to have that info available.
The gun is now outside warming up to the ambient. I'll take a few shots later and see how it looks.
My son and I checked out the pock marks on my burn barrel, and there is a visible difference. It was hitting much harder today.
Another change I made that I forgot to mention. I removed all the felt this time, just in case that was a factor.
Andy
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So, yup, the temperature looks like maybe it's a thing for me.
When it warmed up (ambient 92, it soaked there in the shade for 2 hours) the velocity dropped dramatically. I put the ProChrono DLX out at 40 yards and my phone to capture the data safely away. I set up a sheet of plywood to protect the face of the chronograph (a lesson learned the hard way...) and I'm glad I did. It was peppered with dents from the low shots. Shots were dropping 2' and were very inconsistent shot-to-shot. Out of two dozen pellets fired, only 2 made it through the gate - 306 fps and 201 fps with about 6 minutes between the two of them. Photo 2 shows the impact one of these low-speed pellets had on the burn barrel.
By way of contrast, photo 1 shows what happened in the morning with temperature of the gun about 70 and the ambient slightly lower. I hadn't set up the chronograph yet (those dents inspired me to for the afternoon session).
Andy
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Radical idea...ignore it.
MAybe not worry about it?
Even a leaking o-ring has it's uses.
Put on a known to be leaky o-ring to the 1085 end cap.
Screwed it down tight...popping the 12gr. that was pointed up towards the end cap, pressurizing the tube when the end cap was screwed down.
Cocked/fired the rifle once. Which popped the pointed down 12gr.next to the valve.
Let it sit in the corner for a day so the leaky o-ring would do it's thing and eventually empty the rifle after one cock-n-shot.
(https://live.staticflickr.com/65535/50272694871_a203d88a73_w.jpg) (https://flic.kr/p/2jAqGHe)DSCN2902 (https://flic.kr/p/2jAqGHe) by Robert Dean (https://www.flickr.com/photos/144930793@N07/), on Flickr
HAy...a glance into the future.....welcome to "Old man hands".
LIKELy (and I'll test and show it if need be) would have just shot this rifle 60-70 times...all the while the bottom 12gr.would have been beaten with the piecing pin 60-70times and the pressure holding the valve closed decreasing pressure/closing force at the end....likely have come out empty with about the same sized hole.
But the bad end cap o-ring was useful....in letting the rifle slowly empty itself, showing what actually happens if you load the two 12gr normally.
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That hole in your #1 is monstrous compared to the one I got the other day. Mine was a crack so tiny a #79 drill bit didn't know where it was.
This is getting old. I'm going to try a little more, than call Mike next week if I can't resolve it.
I suspect that the Umarex cans in it now might have both pierced, based on how much better it's working (not that it's good, just that it's way better).
Andy
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I just degassed. Both Umarex cans were opened. After 50 shots the #1 hole was still smaller than a #79 bit.
I got one good shot - the first one. It had been sitting on my bench indoors for 24 hours, untouched. It hit spot on.
Everything after that was dropping.
The most irritating this about this whole episode is that Beeman/Marksman does not return phone calls nor e-mails. So much for a 1 year warranty. :(
Andy
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If I ever have to open it up again, I'll measure how long the valve/actuator assembly is. I didn't do that previously because I didn't see any wear/damage, but it wouldn't hurt to have that info available.
Well, I had a chance to open it up again. Attached are photos of the piercing pin and valve/actuator showing their respective lengths.
I'm still trying to get reliable shot-to-shot performance that is better than 300 fps.
Andy
PS - I spoke with Mike and he doesn't service these airguns. Since I can't get Beeman to return and e-mail or phone call, there is no warranty. So I'm doing what I can, writing it off to lessons learned. Next time I buy an airgun it'll probably be from Mike, so it does have somebody reliable behind it. I'm very disappointed with Beeman, enough that I fixed my review on Pyramyd to reflect the dissatisfaction. I hate doing that, but nobody else should be stuck like this.
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As suggested somewhere above, I made a dummy CO2 cartridge that allows a flow-through operation for the #1 position. The bench grinder cut a nice hole on one end of an old Crosman, and the other end was simply drilled out. The edges were deburred and polished.
The first dozen or so shots were made just to verify that it was working. Then I let it sit for almost 2 days in the 71-degree shop before picking it up at lunch today and shooting through the chronograph.
What was kind of puzzling was the way the velocity dropped, then picked back up. It dropped off quickly after that and obviously was the end of the CO2. Temperature was pretty stable throughout - my shop was about 71, and outside right at 72. I expected some drop in speed from the CO2 cooling off, but was surprised that it picked back up even as I fired about as quickly as possible (all this was with a single shot tray).
Andy
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HAve to think about those first two-three shots...can't see a real logic behind that.
IF this were a PCP, graph would match up to one starting out at too high pressure...working up to a kind of plateau,then falling off. Opening striker force stuggling against the high closing pressure.... as the closing pressure decreased,it got in balance.
With a co2,pressure controled by temperture. Warm co2 at the start (higer pressure),cooling down from being shot and lessening the closing pressure until it ran out of gas?
Harder to judge the internal tempture from the outside...takes time for conduction so we can measure it.
So long as you have the cut-out 12gr., swap the placement....that should check any valve stem limitations that might happen from a tiny-popped hole.
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That over-pressure explanation makes a lot of sense.
What would the solution be? Reducing the spring pressure inside the valve? Increasing the spring pressure on the hammer? Adding weight to the hammer?
I'll try swapping them and see. Early on my problem was not piercing the #1. Having #1 with a drilled-out end takes away that problem. And honestly, getting 60 shots is not a bad thing vs. the 120 when it was new, so I really don't mind having only one providing gas.
Andy
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Usually take the simplest way to find out first and figure a cleaner/nicerway only after finding out if it works.....so shim the strker spring to increase tension.
With the 1085, just taking out the rearaction screw will let you remove the end cap and pluck out the spring. Shouldn't take too much more tension (spacer thickenss) to see atleast the direction of change.
So something quick and simple for a test. Considering how that system works, could just use a washer/spacer between the rear end cap and the plastic spacer.
From your pictures and how far you can protude the piercing pin....not thinking the valve spring goes coil-bound or adds much to the closing force.
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Basically...it's the same thing I'd do for a non-regulated PCP showing that graph.....increase the spring tension to the striker, increase the force opening the valve.
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That was an easy change, and it made a big difference.
I inserted a .060" thick washer at the rear.
This time the #1 was punctured on the first shot. That was my long-term original problem, and it's SOLVED. Thank you!
It also provided much improved velocity, though it still does creep upward for the first dozen or so shots, so maybe a wee bit more shim is needed. It is cutting the efficiency down, though, as it went from about 60 shots to about 40. That suggests either I'm getting liquid into the valve (possible, as there's no felt right now) or the open dwell time is too high. Are those correct possibilities?
Andy
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Somehow I seem to have turned into the 12gr. co2 guy.....but it may just be temp. related.
Good...more spring gave the #1 12gr. a holeand shot better (faster).
Time...conduction....takes awhile for the internal temp to warm up to ambinat...and we can only judge ambinat/external temp. So even a thermomenter stuck to the side of the air tube is going to take some time to "even up" after popping/decompressing 2X12gr.
(Co2 is not cold. It's whatever temp-pressure it's been resting in for a time in. We only think of it as cold as that is the only way we have direct experience with it. Co2 is great at cooling by decompression because it gets a"double dip". Cools by gas expansion and cools by the liquid to gas conversion that supplies the gas.)
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Am still having a fight with my 1085. Accuracy went south on me for no reason I can easily diganose. It'snot a leak, it's not barrel cleaning,and it's not velocity varation related.
No external leak detected. Looked a bit like cooking at one point; flour dusted looking for a possible leak during firing.
Don't know how I could have nicked/bumped/screwed up the crown with a big-azz LDC attached. Shoots the same with the LDC attached or bare-barrled.
Right now. I'm still trying to get it back where it once was....reassembling as I type this after findingfnothing wrong with the internal seals/mechanics.
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Somehow I seem to have turned into the 12gr. co2 guy.....but it may just be temp. related.
Welcome to the club!
I do some online support for the radio control products I develop, and people think I know all there is to know about their type of RC model. Fortunately for them I've been doing it long enough (40 years) that I've picked up a good bit from others even though I don't participate in their exact hobby. I get so many messages asking for help with their airplane ...
But the principles work for RC just like they do for gases. Avogadro, Boyle, Charles, and Amontons laws are all the same.
Time...conduction....takes awhile for the internal temp to warm up to ambinat...and we can only judge ambinat/external temp. So even a thermomenter stuck to the side of the air tube is going to take some time to "even up" after popping/decompressing 2X12gr.
Temperature was getting colder over time, that was pretty obvious. Velocity was going up, though not as dramatically as it had last time out.
Andy