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clyinder to barrel gap and end play
peddler
Member Posts: 881 ✭✭✭✭
I was under the assumption that when you reduced cylinder end play that the barrel gap would be reduced too. What can be done to reduce cylinder to barrel gap? Thanks for any comments
Comments
The only things that can adjust the B/C gap, and head space are cylinder length, and the length the barrel extends inside the frame.
Best
Shims or stretching the crane to take up end shake.
Set barrel in a thread or two, new longer cylinder.
I am fitting a k-22 cylinder to my model 53 Jet. The gap is at least a nickel. I made a plate for the front of the cylinder. It held for a while with just soft solder. One little spot started to bulge. Plan B is to counter bore each chamber .25" with a 3/8" piloted end mill. Silver solder in the inserts, finish ream the holes, then lathe the cylinder face to length.
The factory insets for the Jet chamber work fine, a PIA to reload. Will be much nicer to just hit the ejector rod. Crappy bulk pack 22 ammo works without jamming unlike in my autoloaders.
When the new barrel is installed, there needs to be about 1 thread extra inside the frame. Then the barrel can be trimmed to the proper length for the right B/C gap, and the forcing cone reamed. I prefer the 11 degree forcing cone.
Best
What do you do about the locking lug on the bottom of the barrel, when you set the barrel "in"
Adjustments have to be made...or it has to be compensated for.
You need to deal with three factors: cylinder end play, cylinder to barrel gap, and cartridge to recoil plate headspace.
All three need to be correct.
Cylinder timing may also be affected, so you need to be specific in what you've got conditionwise.
Some lab once tested moderate-pressure .38 Special loads for velocity loss starting with a b/c gap of zero for a baseline. The short story was that at .004, the velocity loss averaged 50 fps, and at .008, the loss averaged 115 fps (net loss of 65 fps over the .004 minimum). Some reloading manual publishers use vented barrels in their testing, so reloaders can better know the ballistics they are actually getting.
With a wildly-excessive gap, especially if compounded by light loads, stuck bullets may become a problem.