Semi-Auto .308 loose primer pockets

[kumaichi]

Not sure this is the right section please move if needed.

I recently acquired a Mega Arms .308 and I've shot handloads (44.0 gr Varget w/175 gr SMKs, 2.800 C.O.L)as well as ammo from Southwest Ammo and this thing keeps blowing out the primers. Then when I go to reload the brass, the primer pockets are to loose to reuse the brass. I've tried Lapua, Hornady and Federal brass. Am I doing something wrong or are .308 Semi-autos just really hard on brass.

Any insight would be greatly appreciated.

 

[K_4c]

Re: Semi-Auto .308 loose primer pockets

I've had no issues running my OBR with 44.0 grains of Varget with 168 SMK's.... Interested to see what others say.

 

[bcrich]

Re: Semi-Auto .308 loose primer pockets

Your load sounds like it is good for a bolt gun and way to high for the gas gun if you are blowing primers, I load my Dpms with 40.5g Imr 4895 and even that seems hot in my chamber using lc cases with 168 amax. I havent blown a primer but they are really flat. Start over and stay safe!

 

[Xcount]

Re: Semi-Auto .308 loose primer pockets

plain and simple if you're popping primers you need to back off the load at least half a grain and start over. Yes, semi auto's are hard on brass, but popping primers is a big overloaded sign that should be dealt with immediately.
There are so many variables in ammunition and rifle compatibility that you can never really start with what other people are using and take it for gospel that it will work in your rifle in all conditions.

The problem today is that guys see load data for a boltgun and use it in a gasgun and wonder why it doesn't work. Before the AR10 you had M1a data and bolt gun data and nobody really mixed the two.
Everybody used 4895 in 308 gas guns for a reason, it works great. Try not to get caught up in the velocity race like many do, use 4895, be safe and learn the wind. The difference in 100fps is usually not even a click on the dials so why pop primers.

 

[kumaichi]

Re: Semi-Auto .308 loose primer pockets

That is the load I use in my bolt gun and it works great. I guess I didn't consider that the load wouldn't work in my gas gun. I'll start over and develop a load for the gas gun.

Just for my own knowledge going forward, do you know of a reason why a load in a bolt gun would be too hot for a gas gun? Would it be a tighter chamber maybe?

Thanks again.

 

[kumaichi]

Re: Semi-Auto .308 loose primer pockets

Thanks Xcount, that's what I was looking for in an explanation. This is my first gas gun so I didn't realize the possible complications using a bolt gun load in this particular gun.

Consider the situation remedied, well, as soon as I can develop a load anyway

Thanks again for everyone's advice, I certainly don't want to blow myself up or hurt someone else.

 

[Xcount]

Re: Semi-Auto .308 loose primer pockets

Chambers will usually be different between AR's and boltguns, the bolt gun will almost always have tighter chambers (which is easier on brass and raises pressure) so in this situation that is not what is causing primer problems, it's too much go fast powder!

Seriously 4895 works great in 308 auto's. there is no need to tip the jug past 42.0g.

have fun.

 

[leadbullet]

Re: Semi-Auto .308 loose primer pockets

my AR10 pops primers with 44 gr varget and 175SMK, backed it down to 43 gr of varget with the 175 SMK and no more problems. I t shoots pretty good to 800 yds too.

 

[BuzzBoss915]

Re: Semi-Auto .308 loose primer pockets

This is a very basic issue. Nobody pays attention to the start low and work up part, they just go for the max load. But, every single rifle is a law unto itself, doesn't matter if it is a self loader, an Encore or a bolt gun. You have to start low and do the drill, find out where your gun's limits are and go from there on the fine tuning.

I don't know why so many people overlook such a basic principle? BB

 

[K_4c]

Re: Semi-Auto .308 loose primer pockets

Did you say Southwest factory loaded ammo blew out primers as well? I have never had any issues with SW ammo in any of my semi's.

 

[Xcount]

Re: Semi-Auto .308 loose primer pockets

that is a classic example of each gun being it's own animal. His rifle might have a .298 groove diameter vice a .300. This causes a big pressure spike and sometimes lower velocity. My .298 barrel shoots as good as anything out there so I wouldn't change a thing, I just had to build up a load for that rifle with no preconceived idea as to where the load should be.

start low and work up, it's simple.

 

[Hi Speed]

Re: Semi-Auto .308 loose primer pockets

BHGM 168's through my LR308=2-3 blown primers per box. Never done it with FGMM 168's. This is a very common issue. I have had 3 barrels on this gun and they have all done it. Load down and enjoy.

 

[K_4c]

Re: Semi-Auto .308 loose primer pockets

I agree with ya. Simple guide line to follow.. But if your blowing primers on factory loads I'd wanna track down the specs on the barrel (tight bore or not) and load off your new findings (as you already stated).

 

[Xcount]

Re: Semi-Auto .308 loose primer pockets

The OP actually might be able to salvage the brass by using Wolf LR primers. It seems they are just a tad fatter (maybe .001") than many other brands and seem to allow another reload from brass that has expanded pockets with say Winchester primers.

I think that most of these comments are coming because of people using bolt guns loads in gasguns. I don't know if any commercial reloaders make a AR10 load specifically but I suspect most of their stuff is designed for boltguns near the top of the pressure range.

 

[Hi Speed]

Re: Semi-Auto .308 loose primer pockets

I put 5000 BHGM 168's through my LR308 at Carl Chandlers place in 2004. He was located in Waco TX. but his wife Alice informed me a year ago he had Passed on to the other side. RIP Carl, Your'e training saved my ass and many others more than once. This was in preparation for fielding the SASS our unit was deploying with on the second go round. I was to train SDM's and the like with it.

I popped a few hundred primers in that two week period. Other than a new trigger group (went full auto at 4500rds) the DPMS ran flawlessly.

 

[kumaichi]

Re: Semi-Auto .308 loose primer pockets

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: K_4c</div><div class="ubbcode-body">Did you say Southwest factory loaded ammo blew out primers as well? I have never had any issues with SW ammo in any of my semi's. </div></div>

That's correct, I bought 500 rounds of their premium 175gr SMKs and the ones I've run through the gas gun blow the primers out, I would say maybe 5 or so per 50 rounds so far. It just sucks because that Lapua brass is expensive and I planned on reloading it.

Thanks for all the helpful advice guys, yep, I'm the typical, take bolt gun ammo and try to run it through a new gas gun. I am going to try and find out what barrel it has on it, just for future reference.