rossi m68 weak strike

B

benji

Inactive
Hello all, long time prowler first time poster. I recently purchased a rossi 68 used from cabela's. I now know I have been too trusting of this major retailer and should have been more inquisitive of their employees. (End rant) Ive noticed several issues with this piece and have begun rectifying them as I can gain more information. I will never rely on this weapon but it has been a great learning experience and my first true experience with gunsmithing.

The question I have for the forum is if anybody knows what, if any, the size of the gap should be between the firing pin and back of the cylinder. I put a few rounds through it and it would fire some but not others but all had primer marks. After confirming there were no hang fires I put the misfires in a well tested .357 and they fired right off. I know these pistols are notorious for the hammer nose breaking and while this one seems to be well formed I think it may be worn. I noticed damage at the bottom of the hole the pin protrudes through which seems to be from the pin striking too low. I figure this clashing may have slowly worn the pin down.

Any help is greatly appreciated, thank you.
 
The relevant measurements to your problem:

1. Firing pin protrusion--how far the firing pin protrudes beyond the breechface. That should be somewhere in the neighborhood of 0.055" for a revolver like yours. You might be able to measure this by placing various feeler gauge thicknesses against the breechface next to the protruding firing pin until you find the one that matches the protrusion length. You'll need the firing pin to be fully forward to make this measurement. You may have to push forward on the hammer spur and hold the trigger to the rear while doing the measurement to be sure.

2. The distance from the breechface to the back of the rim of a chambered round. You'll need a feeler gauge set to measure it. Do it with a fired round (empty case) just to be safe--it won't make a difference in the measurement. I'd expect that number to be somewhere in the range of about 0.006"

If the measurements on your gun are correct, or at least close, then the culprit is probably a weak hammer strike. Either the main spring is too weak/worn out or someone has modified the gun to lighten the hammer strike in an attempt to lighten the trigger pull.
 
Thank you! I'll be checking those tonight for sure, and ill report the results. Any idea as to what may be causing the pin to come in low enough to clash with the breech face?
 
On a revolver that has seen a lot of use and has a hammer mounted firing pin, it's not unusual to see some wear to the firing pin aperture.
 
So I measured the protrusion at .050, could be a little short but I'm beginning to wonder if it wouldn't be worth it to just go ahead and buy a new main spring. Wish I had a way to measure the tension.
 
If the protrusion is good and the headspace (space between the back of a chambered round and the breechface) is good then the spring (or a loose strain screw) is probably the most likely culprit.
 
You must log in or register to reply here.
Back
Top