I have an old Low Wall that has a fairly heavy .22 barrel that came off a High wall (small shank) that I had built quite a few years ago.  There is a gap of about .040 between the end of the barrel and the face of the breech block and a gap of about .020 between the case and the breech block.  This results in a slight bulge at the base of a fired case.  I had one case split yesterday as well.  Here are a few shots.  The second picture shows the extractor fully forward.   cont.....

The rifle showed some promise yesterday buy tended to throw the odd flyer.

Because I don't know anything I get to ask questions.  Why is the extractor Proud of the end of the barrel?  Does the Breach Block lock up on the Extractor?  I would think the barrel could be set back, extractor cut deeper and then the Breach Block would lock up even on both.  But I wish my little Stevens could shoot groups like that.

Set bad with a match chamber is the first thing I would try.   

I have had .22s rupture.  I hate it when that happens    I would not shoot it like that.

Bob,

i have shot it quite a bit.  Recently about 150 rds.  10+ years ago I must have shot 1000 rds through it of all types.  I only had one rupture.  If I were to keep it, rebarriling with a RKS barrel would be my choice.  I would only consider that if I can get a set trigger to work in it.  Based on what Low Walls are listed on Gun Broker, I figure I can get my $800 investment back eventually.

Back to the drawing board.

Another possibility would be to solder a half-circle disc of steel of the proper thickness to the top half of the breech end of your barrel and recut the rim seat in that.

I have a relined Ballard that had the thin metal rim around the chamber fatigue and come off.  The block was then pressing only on the rear of the shell, with no support around the rim, and bursts and cracks would occur.  I made a tiny ring of metal with a hole in the center just large enough for the rim of a .22 shell to fit, thinned it down to fit the headspace between barrel breech and block, and cut a slot for the extractor.

I degreased barrel end and disc, greased up block, extractor and a fired .22 shell, glued disc to breech face with JB Weld, and chambered the empty shell and closed the breech, leaving it closed for a weekend.

I opened the breech (it wasn't glued together ) removed shell and grease, and took it to the range.  No more burst rims, and it's held together ever since.  (Knock on wood.)  I only very rarely clean the bore, and am careful with cleaning solvents, but as there are no side thrusts or pressures, simply having the disc in place for rim support seems to do the trick.

The Ballard was a shot out .22 which had been rebored to .25 RF by the Stevens Co. and shot out again.  The rim seat was oversized, and the tiny circle fits in there.  The block headspaces on the rest of the barrel just fine.

Desperate times, desperate measures.

Since the extractor sits proud of the end of the barrel, it is flush with the block face.  This would prevent any buildup of the block face unless the extractor cut is deepened.  The rifle is kind of growing on me. Reading Campbell's book it looks to be an early panel side low wall which was the first iteration.   I am leaning towards having John King install a RKS .22 barrel on it.  Then if it doesn't shoot the way I like, I will only have myself to blame.  This model with the high block will take High Wall hammers so I could swap out some set trigger parts from another High Wall i have.

Jack

That option of adding to the barrel would probably work.  It is beyond my abilities but there is a local smith/machinist who I have been wanting to try out.  If he can demonstrate to me that he can safely remove the stuck barrel, I may give it a shot.

Jack