Light firing pin strikes

[CubCouper]

Twice in less that three days I've dealt with two different factory *new* rifles (one in 6.5-300Wthby and the other in 338 Lap Mag) that dismantled their own firing pins in a half box of ammo. Two different manufactures, but in both cases the recoil of 10 rounds unseated the set screw that locks the firing pin to the cocking piece. Both had progressively lighter primer strikes until they misfired, barely marking the primer.

Fix is simple enough, tighten with a drop of the blue goo and added a second screw to lock the first in place.

 

[284winner]

Had the same dilemma with a brand-new action I used on a rifle I recently built. Could not figure it out but it wound up being the firing pin spring was too weak. Ordered a 32 lb firing pin spring (a major upgrade from the factory spring) and the problem was solved. It needed a little bit of a pin adjustment but the major problem was the factory spring. I just couldn't believe the factory spring could be the issue being brand new.

 

[BenPerfected]

If you are reloading, another possibility is the shoulders are over bumped. I know a guy that did that

 

[ebb]

I don't understand "over bump". The only way I can see over bump is if the bottom of the die, or the shell holder had metal removed in some way to make them shorter. The same issue could come from a chamber too long. Please help me understand over bump?

 

[dkhunt14]

I don't understand "over bump". The only way I can see over bump is if the bottom of the die, or the shell holder had metal removed in some way to make them shorter. The same issue could come from a chamber too long. Please help me understand over bump?

I have seen dies where they would bump .020 plus. If the chamber is maximum headspace and the die is at minimum or less, it is possible. Matt

 

[Jimmy James]

Rem 700 in 223 with Brux bbl just started having intermittent light strikes (?) would not set off primer 1 in 10 times. 500 rnds on gun. Changed out firing pin assembly with cocking piece and shroud to a Gretan. No more problems.

 

[Dusty Stevens]

Like matt said a good die never touches the shellholder so overbumping is cake

 

[gunsandgunsmithing]

Like matt said a good die never touches the shellholder so overbumping is cake

I actually prefer it to touch some. I use a rockchucker press and want to feel a light cam over. I don't disagree that either will work and that on a production basis, not touching is safest in terms of making sure the phone doesn't ring with problems on the other end of the line.

That said, the die touching or not has nothing to do with proper bump. If all anyone does is set dies by the instructions included with them, it's an almost certainty that they are pushing the shoulder back too far.

 

[Drolds72]

One way to check for excessive head space is to seat long and jam bullet so case is forced against bolt. If those light primer strikes fire, you found it. Downside to this is, if it doesn't fire, and your bullet is jammed, it will pull bullet. point rifle straight up when opening up bolt if safe to do so, so powder stays in brass.