Situation:  Hopkins+Allen .22 falling block, with a new Brownells liner.  .22LR chamber cut w rented reamer from 4D rentals.  Chamber reamer is "sporting, general purpose" style.

Shooting:
With 20 yr old CCI 29 gr CB caps, 700 fps, shoots fine.
New CCI Quiet 40 gr, 700 fps, very difficult extraction.  Gun's extractor lifts it ok, but plucking the shell out is difficult.

Fired shells of the Quiet 40gr ammo show slight bulging by the extractor, where the case may not be fully supported.  

This is really low pressure ammo (I think).  I cut out the barrel liner for the extractor, following the existing pattern, so it should be as designed 100 yrs ago.  

Not sure how to resolve this issue.  Open to ideas.  Is there a different problem, and the slight bulge a red herring?

frnkeore wrote on Jun 28^th, 2024 at 5:46pm:


Yes, that bulge on the extractor side.  Oddly, the case is ok near the very bottom, maybe .22 cases have a supporting band near the base?

I hear you on 922 H+A extractors, De Haas mentioned it in his book, but didn't give details.

Based on what mine was doing, the extractor must be perfectly and tightly fitted to its groove and the chamber in all places.

The bulge looks farther forward than the extractor cutout.  Looks like the extractor is pushing the brass upwards.   

Measure the OD on the two types of unfired brass and see if the CCI quiet is smaller OD than the CB caps.

How well did your liner fit the drilled out bore? Hard to tell from pictures. Perhaps, if the barrel does not support the liner properly, the liner could bulge from pressure?

Is the chamber over size? An oversize chamber with the extractor pushing the case upward will give that bulge, for sure!

gwahir wrote on Jun 28^th, 2024 at 10:06pm:


I cut the chamber into the new liner, using a rented reamer from 4D Rentals.  Cutting was done by hand, no power tools  Reamer was a Sporting/General Purpose style, with a pilot to keep the reamer on-track.   

Idk if the barrel is adequately supporting the liner.  I used a new Brownell's liner drill, and the liner fit smoothly, without obvious slop.  Liner fixed into place w green Loctite, for slip-fit components.   

The test cartridges were CB Longs and CCI quiet LR, both at 710 fps.  I can't believe these would bulge the liner.

I thought the same but wasn't going to say anything. There is a lot of room for improvement. The Brownells liner drills usually cut oversize for a 5/16 dia liner and if there is any run out or misalignment it is worse. You only need .002 to .003 for a slip fit. If the liner on the chamber end isn't supported and a fairly tight fit they will expand under use. What makes things worse is when you cut the chamber the wall thickness is even less. I think you have some compounded issues. I have installed a lot of liners and have had my share of issues and learned from them. 


JMH

I am not sure. The extractor apparently worked for a long time. Should it be modified now?

Extractors are the constant curse of falling block actions!