Firing pin does not strike hard enough

S

soldner61

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Hey guys. Did a recent build on an AR22. CMMG upper with Chiappa 22 bolt and dedicated 22lr barrel. Initially had a feeding and ejection issue. The upper rim of the chamber got burred by a mis-feeding shell.
Polished the feed ramps and a bit of the chamber. De-burred the upper chamber entrance.
Good news is that I no longer have a feeding or ejection issue. Feeds and ejects like a charm:)

Bad news is that another issue cropped up that wasn't apparent before because the gun didn't feed or extract.

The gun does not seem to get a solid primer strike. Now, the performance varies a bit by brand of ammo (better consistency with CCI....and 100% failuer with Winchester....all the ammo I had available to test with)

Firing pin does not seem to be damaged. I had cleaned and lubed everything before testing.

Feedback or ideas would be greatly appreciated.
Thanks
S
 
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I had the same issue that popped up on mine around 500 rds of cheap ammo through it.

I had to take apart the bolt and clean it well. There was powder/carbon residue inside the bolt head itself that effected the striking of the primer. it was like a .001" build up and that was enough to stop it cold.

I was going to make a new firing pin to experiment but never had time.

I dont think the designers of the upper though people would shoot 500 rds in 2 hours in it.

would like to see what other people think. I should rate the ammo I run through it to see whats works and what does not.
 
redbirddog said:
I had the same issue that popped up on mine around 500 rds of cheap ammo through it.

I had to take apart the bolt and clean it well. There was powder/carbon residue inside the bolt head itself that effected the striking of the primer. it was like a .001" build up and that was enough to stop it cold.

I was going to make a new firing pin to experiment but never had time.

I dont think the designers of the upper though people would shoot 500 rds in 2 hours in it.

would like to see what other people think. I should rate the ammo I run through it to see whats works and what does not.
Click to expand...

hmm...were you using the Chiappa bolt assembly?
I probably have less then 500 rds through it so never considered it a cleaning issue....
 
HELP!! Any other ideas out there? Anyway to change the spacing here so the firing pin strikes harder?
Thanks in advance.....
 
I have an M4/Chiappa .22 upper. After installing a Timney drop-in trigger assembly I got a high percentage of light strikes. (The cases actually looked like a solid strike, but the round often didn't fire.)

I wrote Timney describing the problem. They said that problem was common with .22 uppers and that the trigger assembly needed a stronger hammer spring (AR10 spring.) It cost $10, so I bought it. That completely solved the problem. It didn't change the trigger pull weight very much.

You didn't mention using an aftermarket trigger assembly, but I know from this experience (and others) that the hammer spring can often be the culprit with this particular problem.
 
aahhh...thanks. No aftermarket triggers....use my CQ-A lower with stock trigger group
Will look at that route as it sounds reasonable.....
 
Chiappa has an update for the bolt assembly and new firing pin design. Works great but does not like Winchester or Remington ammo. Eats Blazer all day....burp.lol
 
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