What primer to use on a 300 BLK

[papa6x]

I'm working on building a .300 BLK upper for my AR. I'm wanting to get some loads worked up to start with while I'm waiting on parts. I'm wondering what primer would be best to use. I'm using Magtech 7 1/2 for my .223 loads. Would this be OK with the .300 or should I use something else? What do you use?

papa6x

 

[Stschil]

Not well versed so take this for what it is. I have heard from a couple .300 ACC owners that they prefer the magnum small rifle primers. The number/make evades me though.

Added: shibumiseeker[\B] listed the primer I was thinking of. The CCI #41

 

[shibumiseeker]

As it is in an AR platform, CCI #41 primers, or Wolf .223 primers if you want to go cheap. I prefer the harder cups in a semiauto rifle with a free floating firing pin.

I have a 300BLK AR I built, and a H&R Handi Rifle in 300BLK and I'll use whatever small rifle primer I have the most of when I am loading the the Handi Rifle.

 

[papa6x]

Thanks.

 

[Mr Evilwrench]

I've just finished an AR, haven't even fired it. Waiting for the can. You can use shortened and necked .223/5.56 cases, though for some reason I saw a guy with a preference for .221s. I can't remember why. The CCI 41s as mentioned are preferred for the floating firing pin. I haven't looked at supersonic recipes yet since I was able to capture some in the wild, but for the subsonics you'll use a pistol powder.

 

[bigerik]

I use the same primers as my 5.56mm. I use H110 for my 208Amax loads

 

[sloughfoot]

You say "best". Best for what?

 

[gopurdue02]

I would go with small rifle primers and eaither H110 or A1680 for powder. H110 works great for all rounds, except suppressed rounds. For those I use A1680 topped with a 220 Sierra bullet.

 

[papa6x]

You say "best". Best for what?

I was just wondering what primer work better with the .300 BLK, my reloading manual don't list it. I didn't want to load up some rounds to later find out I used the wrong primer.

 

[shibumiseeker]

The 300BLK (no ".") has a very wide loading range, it's not really a round one is going to load for extreme precision, and the powders used are all easy to ignite, so as far as the actual ignition is concerned then any small pistol primer will be fine. The only real concern is the one I mentioned and has nothing to do with the performance of the round: you want a harder cup primer in the AR platform due to the free floating firing pin.

 

[jwh20]

I've been using CCI Magnum Small Rifle primers with good results. I also used some non-magnum primers with equally good results.

 

[papa6x]

Thanks.