cylinder/barrel gap on S&W .38

[mollydodger]

I have an old S&W .38 special revolver. I don't know the model but am trying to determine that as soon as I can post some pics. The previous owner said it shaves lead. In checking it out I have found the rebound does not fit the cylinder notches and I will peen it to widen it a bit. The cylinder notches are in good shape and just need cleaning. I checked the gap between the barrel and cylinder and found a .012 feeler guage will fit. This seems excessive and I need to know if anyone can tell me what is acceptable. TIA.

 

[mmitch]

.004-.006, according to Kuhnhausen's shop manual. Miculek say's .006 in his trigger job video.

Mike

 

[Old Fuff]

I have no idea how "old" is from your perspective, but S&W revolvers made from the middle 1960's backwards often had gaps as wide as .010" because soft lead bullets were the order of the day, and the cylinder face could lead up.

Spitting and lead shaving is more often caused by misalignment between the bore and chamber, rather then barrel/cylinder gap. This can best be checked using a gauge called a "range rod," and you may have to send the gun back to the maker if you can't find a local gunsmith that has one.

 

[dfariswheel]

"Ideal" gap is from 0.004" to 0.006".
Currently S&W says a gap as wide as 0.012" is "in spec".

 

[BBBBill]

...In checking it out I have found the rebound does not fit the cylinder notches and I will peen it to widen it a bit. The cylinder notches are in good shape and just need cleaning...

The "rebound" is correctly known as the cylinder stop. First I've ever heard of peening it to correct fit and I'm pretty sure that not only won't work, but will also cause other problems. Best bet is to send it to someone versed in repairs on that gun. Next best is to educate yourself on proper repair. Get the Kuhnhausen manual, read it well, and decide then whether you want to spend the time, intellectual effort, and money to acquire the proper tools to do the job correctly. Hint - A cylinder stop has several different surfaces that all must be fit to work harmoniously in direct contact with the frame window, trigger pivot stud, trigger nose, cylinder stop notches, and indirectly with other parts. Not to discourage you at all, but to give you food for serious thought.

 

[rcmodel]

My 1980'ish S&W Armorer's Manual says .004" Min - .010" Max B/C gap, with .060" Min - .068" Max headspace is acceptable.

You have to check the B/C gap after all the endshake is shoved forward with a wedge or feeler gauges taking up the slack in the back.

But as Old Fuff alluded to, that is for modern guns with clean ammo.
Very early .38 Spl's had to contend with soft lead, and maybe even semi-smokeless powder fouling at first, so .012" might not be unreasonable.

Also, be sure and check the forcing cone for heavy lead build-up, as that can cause spitting too.

rc

 

[murf]

if it shaves lead, i would also check the cylinder timing.

murf

 

[mmitch]

Midway will sell you an aversize cylinder stop which you can fit by stoning very lightly. It's a trial and error evolution.

Mike