Failure to fire troubleshooting help please

[JWBaldree]

I have a PSA colt mag carbine build that has failure to fire issues. One or two cartridges every mag. The bolt is always forward (I checked, watching it run and pushing forward on the bolt after each cycle to make sure it is fully forward), but I wind up with a click instead of a bang and no or very faint primer marks. Repeatedly trying the FTF rounds in the PCC yields the same results. Any round that won't light off in the PCC readily fires in my Shadow with 13# hammer spring. Yes I'm shooting reloads but all rounds case gauge and plunk. 124s or 147s makes no difference. The firing pin channel is clean and the FP moves freely inside the channel. Right now I'm thinking I need to put in a JP hammer or cut a few coils off the FP spring. Any ideas are greatly appreciated. Build specs below.

 

PSA Colt lower with JP trigger only (hammer and hammer spring are stock)

PSA barrel throated for 147s at 1.16"

CMMG bolt

NFA (I  think) upper and Nordic tube

[OPENB]

Try some factory ammo. If it fires, its your ammo. Are you using lightened trigger and hammer springs? Sorry, just read they are stock. I still would bet on ammo related.

 

Edited July 30, 2017 by OPENB
reread

[Flatland Shooter]

Can you share some info on your reloads?   What primers, how much powder and your bullets. Does the FTF round extract normally when you pull the charging handle?  Any new marks on the rounds after ejecting?

 

If its not ammo related, check the over all length of your firing pin.  

 

I have two Glock magazine based PSA carbines and have not had problems but your's is not the first I've heard of having this problem.  Several times the problem resolved itself with a new firing pin.

 

On the backup carbine, I have the same trigger setup (at least I think so).   It has the JP roller trigger and stock PSA springs, disconnector and hammer.

 

Did you install anti-walk/anti-rotate pins when you installed the trigger?

 

 

Edited July 30, 2017 by Flatland Shooter

[Les Snyder]

did you actually take the firing pin out and inspect it, or just push it forward.... my broken pin exhibited similar characteristics

[JWBaldree]

FTF round extracts normally. No marks on the cartridge. My normal load for everything minor is a Precision Delta 147 FMJ (Berrys as a substitute), 3.5 grains of 231, CCI primers (but also use Federal or Win), 1.16 OAL. I've been using this load for the last 10 plus years. No anti-walk or rotate pins. Firing pin was pulled and inspected, along with the channel. Firing pin flops back and forth inside the channel with no drag. Any idea what length the firing pin should be, and does any one make an extended length pin?

[Aircooled6racer]

Hello: Take the upper off the lower and remove the bolt. Drop a loaded round in the barrel and see how deep it goes in. We have a guy here who had an upper that was reamed so deep that it would fire 38 supers. Measure the bolt recess and also the amount the loaded round is sticking out of the barrel. Thanks, Eric

[JWBaldree]

Loaded round (a FTF) is sticking up .160 from the barrel. Front of bolt to the breach face is .135. Firing pin measures .2.652. Firing pin spring is .840.

[Flatland Shooter]

Has the barrel been reamed?

 

You may want to recheck that plunk test.  With 147 gr plated bullets the longest I can load them is 1.085" with a PSA barrel.  If it does "plunk" your barrel allows the longest AOL of any PSA barrel I've seen.

 

Just to experiment, you might load up some rounds a lot shorter and see if the problem persists.

Edited July 31, 2017 by Flatland Shooter

[JWBaldree]

The leade was throated out with a Manson throat reamer. The chamber area was not touched.

[DFABOVE]

Did the PSA melonite coating present any challenges?

[Les Snyder]

I did my nitrided 16" PSA barrel (my PSA 10" and 7" were ok) to accommodate my 1.140 hand loads... I used a friend's throating reamer that had some use on it... could not get a "bite" using a standard T handle tap holder , and used the tail stock feed and lathe to complete the job