Light Primer Strikes with my Model 1917

[Sentryduty]

Wing nut thing to check from left field, try removing the firing pin and rolling it across a sheet of glass. Look for bends and wobble, had an experience once where the pin would fire occasionally, other times the drag of being "forced" back onto centre by the firing pin hole was stealing enough energy to make ignition unreliable.

Cheap and somewhat easy to check.

[CINDERS]

Would that leave a tell tale shiny spot on the firing pin as another confirmatory sign it was dragging through the bolt head Sentry.

[Sentryduty]

Would that leave a tell tale shiny spot on the firing pin as another confirmatory sign it was dragging through the bolt head Sentry.

I wouldn't think so, because most firing pins are fairly hard metal, but maybe. I have a TT33 that has a bent pin and works 100% reliably, there was no external evidence of the bent pin just odd "scuffs" on the fired primer (bent on the nose end)s of spent brass. Once I pulled the pin and checked it against glass, the bend was obvious. I ordered a $40 (price+shipping) replacement from Numrich but it was too short it wouldn't even fire, so the working but bent original is back in place and shooting fine. The second experience is from my own Civilian AR15, while doing reassembly, which I had done with C7's thousands of times before, the upper and lower was 'hard' to assemble, no obstructions were found and with a bump and it went. Testing again everything would hinge open and closed smoothly, and it passed the function test, but next trip to the range, sometimes it would go click, sometimes bang.

I stripped the bolt and found a bent firing pin, (bent on the tail) and wondered how that could have happened. About 30 second later I had it figured out, military and some civilian rifles have the proper "rounded" hammer but my civvie rifle had a "non-full auto" hammer which had a step cut into the face. If the hammer were not cocked on reassembly, it would strike the aft of the firing pin and bend it. A proper "FA" hammer would just slide past and not cause a concern, I know reassembly with a cocked hammer on SAFE is proper, but over the years muscle memory sometimes shortcuts past "the proper way". Anyway I always kept a spare pin, and for the first time in a decade of firing the AR platform, I found a reason to use it, a minute or so later the rifle was back on the line and running perfectly. Neither one had any scuffs or evidence of the clearance issue.

For reference:



Getting back to the P17, a bent firing pin (or some other drag) could cause light primer strike issues, despite the heavy springs, it would hopefully be the lowest cost and least hassle fix for this rifle, it would be a shame to see a guy have to search out a new bolt, or mess about with headspace.

[fjruple]

Also check for debris inside the firing pin hole inside the bolt. Either dried grease, cosmoline or a piece of primer could have been blown back through the firing pin hole.

--fjruple

---------- Post added at 05:54 PM ---------- Previous post was at 05:50 PM ----------

I'll bet it was slightly pitted. He probably never intended to shoot it and couldn't have imagine anyone else shooting such a perfect example...with a shiny bolt face...proving it had never been shot before...

I have seen the same thing happen to a mint .455 Colt New Service converted to .45 Colt. Instead reaming out the chambers like any normal gunsmith. The bubba shaved off .02 of metal on the back of the frame!! The revolver was ruined.

--fjruple

[Garand]

I have tried 3 different strikes and believe me the bolt and the firing pin hole are exceptionally clean.

[Detroit-1]

You still have not checked head space? Sounds just like a M39 I had. Had to make the firing pin protrusion .015 over to get it to fire. Otherwise it had light strikes.

[browningautorifle]

Had to make the firing pin protrusion .015 over to get it to fire.

We discussed it at lunch...and came up with exactly what you suggest. Eventually I'll have the bolt in hand and sort this out, we'll get back with results for all.