22XX Probes, Bolts, Breeches, O-Ring Question's...

22XX Probes, Bolts, Breeches, O-Ring Question's...

Joined: December 29th, 2009, 3:08 pm

November 21st, 2011, 10:16 pm #1

I'm building up several 22XX guns, pistols and rifles and I'm having the same problem on all of them.

My bolts are binding in the breeches and during assembly I mount the barrel in the breech and close the bolt and my o-rings are showing through the breech transfer port hole, is this how it should be? Locking the bolt handle down is tight, and although its better than slop and the bolt opening during firing, I think its just a little too tight.

I have a whole collection of bolts, probes from various suppliers and I usually find I have to mix and match probes and handles to get smooth operation. I have particular problems with .177 probes in stainless from SD Custom design which as I understand are made by Don Cochran. I'm not trying to slate anybodys work here, just understand the problem. The problem is probably the idiot putting them together! ;^)
I really want to use the stainless bolts as they a beautifully made and look really good on my new blue and stainless .177 target pistol.

It could of course be my stainless breech causing the problem. Also I'm ripping up O-rings despite checking for and cleaning up burrs in the barrel. I put this down to the o-ring entering the barrel, instead of sealing around the face of it, and hitching in the transfer port hole.

Any ideas guys? Thanks
Last edited by Specman on November 21st, 2011, 10:47 pm, edited 1 time in total.
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Joined: June 30th, 2011, 11:13 pm

November 22nd, 2011, 1:05 am #2

I have a DC SS breech which had the difficult to move bolt as you described. It was explained to me that his tolerances are very tight and that with use, the bolt will move more freely. I found this to be true, yet the bolt still does not move as easily as I had expected. The oring on the DC probe definitely slams the leade area of the barrel more snugly than other pistols I have.

I put an aftermarket extended probe bolt in a Crosman steel breech and the dang thing started off great on the cock and would be nearly impossible to pull all the way back unless I backed off the bolt handle by a single turn. Suffice it to say I had to file and sand the bolt handle down so it would work well.

Though I never looked for the bolt probe tip though the transfer port of the barrel, it makes sense that you can see it. The probe needs to seat the pellet forward of the port.
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Joined: November 17th, 2006, 3:51 am

November 22nd, 2011, 1:33 am #3

I'm building up several 22XX guns, pistols and rifles and I'm having the same problem on all of them.

My bolts are binding in the breeches and during assembly I mount the barrel in the breech and close the bolt and my o-rings are showing through the breech transfer port hole, is this how it should be? Locking the bolt handle down is tight, and although its better than slop and the bolt opening during firing, I think its just a little too tight.

I have a whole collection of bolts, probes from various suppliers and I usually find I have to mix and match probes and handles to get smooth operation. I have particular problems with .177 probes in stainless from SD Custom design which as I understand are made by Don Cochran. I'm not trying to slate anybodys work here, just understand the problem. The problem is probably the idiot putting them together! ;^)
I really want to use the stainless bolts as they a beautifully made and look really good on my new blue and stainless .177 target pistol.

It could of course be my stainless breech causing the problem. Also I'm ripping up O-rings despite checking for and cleaning up burrs in the barrel. I put this down to the o-ring entering the barrel, instead of sealing around the face of it, and hitching in the transfer port hole.

Any ideas guys? Thanks
..though the transfer port. Probably would work OK if more than half of the o-ring diameter was to the rear of the port (just a little wink of o-ring showing) but the bolt should not be entering the barrel that far.

If you are dead sure all the transfer port holes line up (from valve body to bore), am wondering how the bolt gets inserted that far into the barrel.'''just playing at the bench with a spare barrel and a bolt, think I'd have to beat it in with a ball peen hammer to show o-ring in the port.
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Joined: April 28th, 2008, 6:45 am

November 22nd, 2011, 6:23 am #4

I have a DC SS breech which had the difficult to move bolt as you described. It was explained to me that his tolerances are very tight and that with use, the bolt will move more freely. I found this to be true, yet the bolt still does not move as easily as I had expected. The oring on the DC probe definitely slams the leade area of the barrel more snugly than other pistols I have.

I put an aftermarket extended probe bolt in a Crosman steel breech and the dang thing started off great on the cock and would be nearly impossible to pull all the way back unless I backed off the bolt handle by a single turn. Suffice it to say I had to file and sand the bolt handle down so it would work well.

Though I never looked for the bolt probe tip though the transfer port of the barrel, it makes sense that you can see it. The probe needs to seat the pellet forward of the port.
Utter rubbish.

I spent some time working nights in a small owner run cnc shop. Quality control is there...or it is not.

Parts that don't work as expected should not be leaving the shop...period. Stating "tight tolerances" as an excuse is pure BS...it's poor quality control.

Al
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Joined: December 29th, 2009, 3:08 pm

November 22nd, 2011, 8:18 am #5

..though the transfer port. Probably would work OK if more than half of the o-ring diameter was to the rear of the port (just a little wink of o-ring showing) but the bolt should not be entering the barrel that far.

If you are dead sure all the transfer port holes line up (from valve body to bore), am wondering how the bolt gets inserted that far into the barrel.'''just playing at the bench with a spare barrel and a bolt, think I'd have to beat it in with a ball peen hammer to show o-ring in the port.
No more, but the question is should you see any of it if it is supposed to be sealing on the barrel shoulder? This is with a .177 probe BTW. Thanks
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Joined: December 29th, 2009, 3:08 pm

November 22nd, 2011, 9:12 am #6

I'm building up several 22XX guns, pistols and rifles and I'm having the same problem on all of them.

My bolts are binding in the breeches and during assembly I mount the barrel in the breech and close the bolt and my o-rings are showing through the breech transfer port hole, is this how it should be? Locking the bolt handle down is tight, and although its better than slop and the bolt opening during firing, I think its just a little too tight.

I have a whole collection of bolts, probes from various suppliers and I usually find I have to mix and match probes and handles to get smooth operation. I have particular problems with .177 probes in stainless from SD Custom design which as I understand are made by Don Cochran. I'm not trying to slate anybodys work here, just understand the problem. The problem is probably the idiot putting them together! ;^)
I really want to use the stainless bolts as they a beautifully made and look really good on my new blue and stainless .177 target pistol.

It could of course be my stainless breech causing the problem. Also I'm ripping up O-rings despite checking for and cleaning up burrs in the barrel. I put this down to the o-ring entering the barrel, instead of sealing around the face of it, and hitching in the transfer port hole.

Any ideas guys? Thanks
perhaps that is where I'm going wrong here. Crosman have the standard brass bolt in a plastic breech. Can't see them faffing around for hours to get one to work correctly. Can you?
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Joined: November 9th, 2010, 10:37 pm

November 22nd, 2011, 9:20 pm #7

I'm building up several 22XX guns, pistols and rifles and I'm having the same problem on all of them.

My bolts are binding in the breeches and during assembly I mount the barrel in the breech and close the bolt and my o-rings are showing through the breech transfer port hole, is this how it should be? Locking the bolt handle down is tight, and although its better than slop and the bolt opening during firing, I think its just a little too tight.

I have a whole collection of bolts, probes from various suppliers and I usually find I have to mix and match probes and handles to get smooth operation. I have particular problems with .177 probes in stainless from SD Custom design which as I understand are made by Don Cochran. I'm not trying to slate anybodys work here, just understand the problem. The problem is probably the idiot putting them together! ;^)
I really want to use the stainless bolts as they a beautifully made and look really good on my new blue and stainless .177 target pistol.

It could of course be my stainless breech causing the problem. Also I'm ripping up O-rings despite checking for and cleaning up burrs in the barrel. I put this down to the o-ring entering the barrel, instead of sealing around the face of it, and hitching in the transfer port hole.

Any ideas guys? Thanks
and found quite a bit of variation in the distance between the bolt handle and the o-ring.
If the bolt is too tight you should loosen the screw holding the barrel in the breech then close the bolt. This will push the barrel forwards a little to take up the extra bolt length. Then re-tighten the barrel in the new position.
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Joined: December 29th, 2009, 3:08 pm

November 22nd, 2011, 10:16 pm #8

and come to the conclusion that this may be the problem. The error can occur as you say, between the bolt handle and the O-ring. For what it is worth for anybody else experiencing similar problems, GMAC probes are a perfect fit, at least in Crosman and GMAC breeches. The fitting instruction from Gordon is fit the barrel hard to the breech, align transfer port and tighten grub screw. Next check bolt operation, o-ring should NOT be visible.

Thanks to all who responded to this thread.
Last edited by Specman on November 26th, 2011, 10:09 am, edited 1 time in total.
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