Use Magnum primers?

[bearcatrp]

On another forum, someone suggested to use magnum primers for 300 BO. Anyone try this with good results? Increase in fps? Or is this a bad idea? Thanks.

[gaijin]

That would depend on powder you're using.

I find that even with H110, which is notoriously difficult to ignite in straight wall handgun cartridges WITHOUT magnum primers, they have not been necessary in 300 Blk.

[QuietMike]

I use CCI 41s, which are magnums for all my AR loads.

[bearcatrp]

Will buy a pack of 100 to see if its any better. I use H110. Will chrono them and compare.

[Sharkbite]

I tried both std primers and mag's in my H110/296 load.

Thats what I use in my max 125gn load. I saw a reduction in ES with the mag primers when shooting in extremely cold weather (< 10 degrees)

Was it enough to make a real world difference? Not for me to stock a special primer that id only use in that one specific load. The std primers gave velocities that were just as high, just a little bit more spread, shot to shot.

[blaster]

I have tried magnum, standard and #41 primers and couldn't see a difference. I mainly tried the #41 & mag. primers because of the harder primer cup. since for many years of shooting standard primers out of Mini 14 s and AR 15s with no slam fires, I decided that it was a non issue and now only use standard primers in my 556 & 300 BLK loads.

[bearcatrp]

Thanks guys. Will still buy some just to see for myself. Have a large amount of regular small rifle primers so no plans to dump them. No sense spending money for minimal results.

[John A.]

I've been using Rem 7-1/2's with my pet loads.

I also use 7-1/2's for my hot 357 magnum loads too.

Matter of fact, I think either hogdon or perhaps hornady shows load data for 357 maximum using 7.5's.

Would it be ideal for anything and everything? Probably not.

[cwlongshot]

You will not hurt anything no.

Personally, I do not see the need. But try them, your results could vary.

Enjoy!

CW

[plant.one]

folks regularly use magnum and non magnum primers for the caliber. i think a lot of it has to do with personal preference and/or availability.


just remember, if you decide to switch primers, back up and do some load development like you would with any other component change (powder, bullet, etc).

dont just take your pet load and swap the primer over and hope it'll still be safe. I'm not suggesting that it WONT be... but that can only be determined by testing.


safety first!