how much firing pin protrusion for a Uberti revolver?

[stepnmud]

Have a pair of Uberti Cattleman 44Special revolvers, 4 yrs. old and have been used fairly regularly at Cas Matchs. This past year, I'd been getting some lite primer hits and sometimes might go off second time around. Anyhow I had replaced the bolts & hands and the timing and lock up seems OK and also replaced the light main springs with original main springs. At yesterday's Match the first revolver failed to fire at all and looking at the firing pin protrusion was barely noticeable, after I got back home for a closer look at the firing pin, it has enough looseness to go forward or backwards thru the frame but the pin can protrude far enough and can push it back into the frame almost flush with finger pressure. I have drill rod .0820 #45, .0860 #44 to use for the firing pins and the original firing cross pins seem to be bent some. Not sure if the new firing cross pins will be enough and thinking to size up the new cross pins to the .0860 and would have to drill out for the bigger cross pins. Is it possible that the firing pins themselves have been wore out in the firing pin hole?

Update:
OK, now I'm looking at a Gunsmith book on revolvers by Patrick Sweeney and mentions the firing pin protrusion should be more than .040 and less than .050 and if less, then firing pin needs to be replaced.

[Coffinmaker]

Well ....... the firing pin may not be the problem,by itself.  You should not be able to push the firing pin back and fourth in it's bore in the hammer.  Firing pin extension should be 40 - 50 thou, and STAY there.  In some Uberti guns, there are parts under the firing pin, retained by the firing pin and its cross pin.  If those parts are missing or smushed by wear/use the firing pin will move back and fourth.  Not a good thing.  Usually, a warn firing pin is obvious with distinct mushrooming of the nose of the firing pin.

The firing pin should not be able to move in the hammer beyond the slot cut for the cross pin.  If it does, it will begin to cut the cross pin and become very lose.  Normally the cross pin is very soft for staking in the pin bore.  You may need to make a shim to fit under the firing pin, aligning it with the cross pin bore and establishing 40 to 50 thou extension.

So take it apart, wiggle it around and see what's under there.

Coffinmaker

[Montana Slim]

..... and the original firing cross pins seem to be bent some. Not sure if the new firing cross pins will be enough and thinking to size up the new cross pins to the .0860 and would have to drill out for the bigger cross pins. Is it possible that the firing pins themselves have been wore out in the firing pin hole?

I suspect the cross-pins are the root cause of problem.
I've replaced one each in an 1873 Colt Clone & 1875 Remington Clone.
If something in the system is gonna "give", the X-pin is a good place for it to happen.

Regards,
Slim

[stepnmud]

thanks for the info.
So far so good, went to the range today and burned up two hundred rounds of 44 specials in the revolvers and checking the firing pins that I worked on. all spent cases looked to be good solid firing pin hits. Probably would have been easier to have ordered new firing pins from VTI for $8.00 each and mostly likely still will get new ones.
After removing the firing pins, the cross pin slot looked to be wallowed out and drilled out the hole/slot with 1/8" bit and had some 1/8" brass to fill back in with using loctite(not sure that helped any) and drill new .0860 holes for the new cross pins .0820 as thats what seemed to be the existing for the hammer pin holes. Made the firing pin protrusion a shade under .050 and alls well for now, not sure how long this fix will work, but at least I got in a bit education. Have read about hardening or buying hardened firing pins as these originals are now all polished up and bare metal, but will see if they will last for now.

[Driftwood Johnson]

Howdy

Kuhnhausen specifies that firing protrusion should be .045 Min, .056 Max.