New R3 .25 issue – breech seal too thick/bolt binding
Just an FYI to all the new .25 owners if they have a similar issue. Unfortunately I forgot to take pictures.
While my new long .25 shoots great, as received the shroud was lightly touching the knurled portion of the air reservoir that surrounds the gauge. The bolt was also a little stiff trying to get it closed the last inch or so.
After looking closely at the rifle I noticed there was a .030″ gap between the breech block and the air reservoir. This explains why the front of the shroud was rubbing the air reservoir as the barrel was effectively running “downhill” because the breech block wasn’t fully seated against the air reservoir.
The “downhill” barrel was also the reason why the bolt action was difficult; the bolt housing was bolted down firmly to the air reservoir at the rear but held up at the breech block– thus the bolt was trying to enter the breech at an angle and as more of the bolt enters the breech the greater the angular mismatch and closing effort.
After disassembling the rifle and measuring things to find the source of the problem I found that the brass sealing washer between the breech block and the output of the regulator was too thick. This prevented the breech block from tightening down flush against the air reservoir. With the brass sealing washer removed the breech block bolted down firmly against the air reservoir making the barrel parallel to the air reservoir. That fixed the shroud touching the knurling and also brought the breech and barrel in-line with the bolt and fixed the difficult bolt action.
Knowing there was .030″ of gap between the breech block and air reservoir with the sealing washer installed I used 400 and then 800 grit sandpaper to lap .026″ off the breech sealing washer; that would leave about .004″ of crush for a good seal.
After lapping the sealing washer and then reassembling the rifle the gap between the breech block is gone; the barrel is now parallel to the reservoir, the shroud is no longer rubbing the knurling at the gauge, and the bolt action is very smooth and easy. The rifle also passes the “tissue paper” test with the lapped sealing washer– i.e. put a single layer of tissue paper over the entire breech area, fire it, and watch for the paper to jump which would indicate an air leak.
On the positive side, the rifle shoots great– it was set out of the box for 885fps average with JSB Kings and on the only string I chronographed last night it managed to spit out 82 shots at 885 +/- 8 fps from 210-105 bar without any regulator or hammer spring adjustment. Once I get about 700 pellets down the barrel and things wear in some I’ll try tweaking the regulator & hammer spring to get the extreme spread down.
I’m also happy Ed decided to machine some cant into the scope rail of the R3; using standard rings there are 3 mils down / 17.5 mils of up elevation left in the scope from a 50 yard zero. That’s enough elevation adjustment to get out to 200Y without having to start using reticle holdovers! However if anyone is using a scope with less than 20 mils (~72 MOA) of adjustment range they might have a hard time zeroing at 50 yards unless they use something like Burris Signature Zee rings with offset inserts. With my .22 R2.5 zeroed at 50 yards that rifle only has 11 mils of up elevation left in the scope even using Burris Signature Zee rings with offset inserts for ~20MOA of cant.
Looking forward to receiving my R3 .22 standard. 😀
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Viewing 5 replies - 1 through 5 (of 5 total)
Enjoy shooting!
Regards,
Endo
You are correct. R3 .25 using brass o-ring instead of rubber in transfer port.
Hi Kiba, Nice Edguns who have there!!
Last weekend after sighting in my Edgun .25 cal long gun, I ran out of downward elevation. I actually didn’t bottom out but I was about 5 clicks from doing so. I read your post and started to analyze my gun based on your information. I noticed that there was a gap between the tube and breech just like you did. The muzzle end of the shroud was not touching the knurled end of the tube though. It was close, but not touching. Therefore the barrel was pointing at a downward angle relative to the tube. To position the shroud/barrel parallel to the tube, I followed your procedure on lapping the brass ring. I did the trial and fit method until I felt it was parallel. Incidentally, the gun is very easy to take apart and put back together. After getting every put together this morning, I tested for “blow by” using the tissue method. No blow-by 😀 . I ran a few shot over the chrony and it read at a steady 900 fps using jsb kings. I also noticed pushing the bolt home, it was smoother and required less force. I knocked down the lip where the cocking shoe runs (rail ?) according to OG posting and that also helped in the smooth department.
I’m going to shoot this afternoon and see if the modification to the brass ring made a difference on the point of impact. Since the shroud, scope rail, barrel, and part of the breech assy are all one modular piece, I don’t know it the point of impact will change much. I hope it does so I don’t have to shim. At least I got some experience tearing down the rifle and know that everything is lined up to my standards.
Thanks for the post Kiba. It helped me out trememdously.
Gabe G.
All is still working well with the long .25.
I did purchase some annealed “dead soft” aluminum tubing with the same ID and OD of the original brass breech sealing washer– I figured if I lapped the brass sealing washer too thin and developed a leak I could easily part off a small piece of the dead-soft aluminum tubing on the lathe to make a new breech seal. The annealed aluminum washer should “crush” a little easier than the original brass sealing washer too.
I’m *really* liking the hitting power of the long .25 for hunting but it’s overkill in terms of power and noise for paper punching and critter control in the backyard with neighbors around. I think the .22 is going to become my backyard paper puncher and “critter getter” while the .25 will be saved for critter-control out in the orchards.
Also, pictures! Both the .22 R2.5 and the .25 R3 are wearing Bushnell Elite Tactical 3-12 x 44 FFP scopes in Burris Signature Zee rings with Holland’s 30mm anti-cant levels. While the standard length R2.5 .22 has served me well for quite a while now it will be replaced as soon as my new standard length R3 .22 arrives. 😀
Kiba, thanks for the info. A rubber o-ring is used in the transfer port for .22 Standard. I just wondered if the long version of R3 uses brass o-ring.
Enjoy shooting!
Regards,
Endo
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Shot a few rounds and the poi stayed the same. That’s what I was expecting.
Learned how to take her apart and the breech action is smoother. Good good!
I was shooting 25 yrd targets. I also had a chance to drop some shots down field. Prolly 60 yards. This gun is not only accurate it is a beast.
Hits like a sledgehammer.
I just need to play around with the trigger to lighten the first stage a bit.
I thinking about getting a .22 cal standard
These things are greAt!
Gabe