Hello, I am new to this forum but need some help. I recently purchased a used S&W N frame revolver with 0.020 barrel gap and a lot of blow by. I am trying to find out how to decrease this gap without increasing barrel wobble. Thanks for any help. David.
First of all, welcome to the forum! Second, put your tools back in the toolbox. Third, call S&W and get a shipping label, etc. Reason why is simple. If your measurement of the BC gap is correct, the necessary correction will exceed your abilities unless you are really good w/ a lathe, thread cutting, setting headspace, etc. Sincerely. bruce.
Thanks Bruce. I am a seasoned machinist and have access to milling machines and lathes, and am able to pick-up on existing threads to thread longer. My mechanical knowledge is sound, but my gun assembly knowledge is limited, like not knowing how to remove the barrel from the frame without warping the frame or destroying the firearm. I prefer to gain knowledge before jumping into the unknown without an informed game plan.
Thanks for the link and information. I do not see and flame cutting and not much wear or wobble. The cylinder is recessed and in great shape, I believe the gun was made between 1972- 1974, according to the s/n. I will definitely purchase a book on S&W revolvers.
Welcome to the forum from a retired gunsmith. Correct B/C gap is .004-.008, .020 is definitely excessive. To close it the barrel would need to be removed & the shoulder turned down or the barrel replaced. Turning it down works if it doesn't affect the front lock too much. Because it moved the lock back it can be resolved by shortening the elector rod a few thousandths... unless it's just too much (in your case likely) where a new barrel is needed.
I have been wondering the same thing. Was someone using it for a parts gun (the rear sight is missing)??? Does the cylinder color really match the rest of the gun??? Either way, I purchased it, now it is mine. What to do next? Send it off or take it to a local gunsmith, OR, do I use it as a learning tool to test my (supposed) abilities? I am always willing and wanting to learn, and extend my knowledge, ability, and skill level.
If you have a mill you could make the jig & wrench, however if you're not familiar w/ gun work you'll save a bundle hiring it done. How about a picture to see the difference in frame/cylinder? Was the sight removed for a scope mount? Pictures can tell a lot.