WMSRL #41 failure to ignite

[dellet]

When the bolt action 300 Blackout rifles started coming out, there were a lot of failure to fire problems. Ruger caught the brunt of the complaints and did have an extractor issue that did not help. The problem started showing up more and more with factory ammo, so a few of us started measuring new out of the box ammo and brass.

Here's what we found, remember 1.070" is a bit short by SAAMI spec.

Sellior and bellot 1.055
PNW Range 147's 1.068
team never quit range 1.066
ADI 144 1.064
Nosler 110 1.066
Remington green yellow subs 1.065
Hornady 110/220 1.055
Barnes/rem 1.065
Gemteh 187 -1.065

Rem 115gr CTFB (discontinued) 1.0725"
Rem Express 220gr OTM 1.0720"
Rem UMC 220gr OTM FB 1.0700"
Nosler 125gr BT 1.0785"
Federal AE 220gr OTM 1.0730"
Atlanta Arms & Ammo 125gr Pink Tip (discontinued) 1.0700"

 

[thumper3181]

This is what the problem is and a slightly harder primer than normal. I still can't believe that Starline has this low of quality control, some are .012 to .015 too short off of the shoulder.

 

[searcher]

Yes, I know. But I didn't resize these cases, they came that way from Starline.

Did you size the cases before loading? Sometimes, that will lengthen the case (and the base to shoulder measurement) such as when doing so to fired brass. Doesn't take but a few thousandths to rid your problem, most likely. If the cases were "short" and sizing doesn't help lengthen the measurement - you are in a bit of a pickle as you don't want to load AR ammo long enough to jam in the throat. You could either shoot the brass in a bolt gun where you can load long - or you could blow out brass with a hydraulic forming die - or just load and shoot and put up with the misfires until you get though all of your brass being fired. That you are having this happen only with one brand of new brass - it again points to a headspace problem.....
Good luck

 

[Webster]

I was working up some loads with these and out of less than fifty I had 5 failure to ignite, from two different gun. One Ruger American in 300blk and an AR-15 pistol in 300blk. On the ones that did fire I had decent SDs, so I'd assume that when they do ignite it's a consistent ignition.

Are you setting the primer to the bottom of the pocket? Setting to a certain depth can be bad news if the firing pin pushes the primer cup deeper.

 

[NorCalMikie]

You could also take each round that FTF, pull the bullets out a but so the OAL is to a jam, single feed, fire that round and make sure you arn't pushing the shoulders back to far and you end up with the same problem, all over again.