Texas Hunting Forum

Blown Primers In AR

Posted By: Rob M

Blown Primers In AR - 08/03/17 04:55 PM

Hey All,

I have been running into a new issue lately with my .300 blk. I am running a suppressor on a 14.5 inch barrel, and I am getting a bunch of blown primers, which is causing my BCG to jam up. This is extremely poor timing too because it's while I'm blasting at groups of hogs, so I don't needed these jams. Any idea what would be causing the primers to blow? I have never ran into this before.
Posted By: Gemlin

Re: Blown Primers In AR - 08/03/17 05:11 PM

Your loads are too hot or bad headspace
Posted By: ChadTRG42

Re: Blown Primers In AR - 08/03/17 05:13 PM

Yes. 1 of 2 things. Most likely, the ammo is too hot for your rifle. Or, the brass used has loose primer pockets to begin with and the primers are falling out upon firing. I have seen this with some fired 223 brass cut down for blk out.

What ammo is it, and what bullet are you shooting? Components?
Posted By: kmon11

Re: Blown Primers In AR - 08/03/17 05:47 PM

New ammo? New gun? suppressor new?
Posted By: Hunter-Steve

Re: Blown Primers In AR - 08/03/17 08:32 PM

Just curious.. I have had this happen with some less than snug primer pockets. Would Primer sealer help with preventing this?
Posted By: ChadTRG42

Re: Blown Primers In AR - 08/03/17 09:00 PM

Originally Posted By: Hunter-Steve
Would Primer sealer help with preventing this?


No. Primer sealer is to keep moisture or water from coming in. But it does nothing to help hold the primer in the case.
Posted By: DStroud

Re: Blown Primers In AR - 08/03/17 09:11 PM

I have seen over gassed AR's push primers out as well. If you have an adjustable gas block maybe a little tuning would correct.
Posted By: Rob M

Re: Blown Primers In AR - 08/04/17 02:43 AM

To answer a few questions.... yes, it's a new gun, running a suppressor, and have adjustable gas block.

My thought was that the suppressor was causing it to be overgassed and I need to open the block some. It's not happening every round, but definitely 20% of the time. I'm getting on pigs and squeezing away, but then get a stoppage from the bolt being jammed up due to a blown primer.

Chad, I'm running the 125 grain SST's I got from you a couple weeks ago. You think they are too hot for the 14.5 inch barrel?
Posted By: DStroud

Re: Blown Primers In AR - 08/04/17 03:23 AM

Actually close the block down not opening would possibly help.
I usually close it completely then start opening until a hull is ejected then open just a tad more for insurance
Posted By: blackcoal

Re: Blown Primers In AR - 08/04/17 03:44 AM

Could be ammo issues. Hope you get it figured out, I'd hate to pull the trigger and find out the action is jammed.
Posted By: ChadTRG42

Re: Blown Primers In AR - 08/04/17 03:27 PM

Ok. Yes. My 125 SST load is a max load. What's happening is about 3 things at once. Your adjustable gas port is adjusted too far open allowing too much pressure coming back. And with it being a short barrel and suppressed, and probably on a pistol length gas system (gas port is closer to the chamber than a rifle length gas system for even more pressure) you are allowing too much pressure to the action. The whole concept of having an adjustable gas port is to tune the cycling to the ammo you are shooting.

First, you need tune the gas port. To do this, close the gas port to it's lowest setting (not opening it more) and fire a few rounds. Closing it will decrease the gas port opening and reduce the amount of pressure coming back to cycle. If it cycles on the lowest setting, leave it there and run it. If it doesn't cycle it all the way, open it up some little by little until it does. Consult with the mfg of the gas port for specific tuning. I know there are YouTube videos on this, and I'm certain the gas port mfg can help you with it also.

Being a short barrel, 14", running suppressed and having the gas port open too far, all 3 of these things in combination together can easily increase the pressure too much. Adjusting the gas port will certainly solve your issue. Feel free to buzz me and let me know how it goes.
Posted By: ChadTRG42

Re: Blown Primers In AR - 08/04/17 03:54 PM

Originally Posted By: blackcoal
Could be ammo issues. Hope you get it figured out, I'd hate to pull the trigger and find out the action is jammed.


It's not an ammo issue. See note above.
Posted By: Rob M

Re: Blown Primers In AR - 08/04/17 05:53 PM

I'm gonna adjust it tonight when I get to the house. I figured it was a pressure issue, just wanted to make sure before I started jacking with anything. I will post an update in the morning.
© 2024 Texas Hunting Forum