clyinder to barrel gap and end play

peddler

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

tsr1965

Usually, end play is adjusted using shim spacers of some sort. That can also effect the B/C gap, and head space.

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

peddler

I adjusted end play with shims but still have .023" barrel cylinder gap. Seems way too much for me but little revolver is getting a better barrel next week. Maybe cylinder gap will be better with the other barrel. Thanks

charliemeyer007

Depends on the gun. A shoe could be fitted to the shank of the barrel that sticks out past the frame. Insets could be added to each chamber in the front of the cylinder.

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.

tsr1965

The B/C gap should not be over 0.006". I prefer 0.002"-0,004", with minimal end shake, and the correct headspace.

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

peddler

What do you do about the locking lug on the bottom of the barrel, when you set the barrel "in"

tsr1965

quote:Originally posted by peddler
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.

spasmcreek

measure ..turn the barrel shoulder down..replace and measure and turn end of barrel down to 0.003-4 and touch up 11* forcing cone ..turn back end of ejector housing down so mounting hole aligns with threaded hole in barrel...done a number of 22 revolvers this way...some of the import had huge cylinder gaps and this puts the oomph down the barrel not blasting out the sides...heard there was an optimum %+ size to finish forcing cone OD to land and groove ID but never could find what the ratio was ???

v35

Are you talking S&W s and Colt DAs or SAA Colt type revolvers?
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.

machine gun moran

S&W used to say that .004-.006 was factory new spec for b/c gap, and anything over .010 was in need of adjustment. .004 was judged to be needed to allow free cylinder rotation in the presence of metal fouling on the cylinder face and the breech end of the barrel.

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.

peddler

Thanks this has been real helpful