Magnum primers, yes or no?

[daved20319]

So I'll be getting back to my Grendel in the next few weeks, and am planning on ordering a bunch of primers for this and my other guns. Seems like a lot of Grendel loads call for magnum primers, but there's also a lot of folks that say they're not necessary. Is there a definitive conclusion on this, or is it still kind of up in the air? Thanks.

Dave

[Mesa1978]

Thicker cups, if you are shooting semi-auto/AR with floating firing pin, extra margin.

[sbowhuntr]

I took the advice of the guys on here when I started loading for the grendel. They recommended cci 450's and I have had great results with them and never a slam fire.

[A5BLASTER]

Short answer= yes

Long answer= when I decided to go down the rabbit hole of handloading this fourm told me cci450 primers would be the best choice.

Haven't regretted it yet, I'm useing them in all my loads both ar and bolt grendel.

[Popeye212]

Have yet to find a better all around performer in my Grendel load than CCI450. Pet Creedmoor load uses em also (SP brass).

[Lemonaid]

On PrecisionRifleblog.com the pros use CCI 450 5 to 1 for the 6mm Dasher. https://precisionrifleblog.com/2019/09/0...load-data/

[daved20319]

Thanks, guys, magnums it is.

Dave

[Mitdr774]

When using CCI primers I have had better results with the 450 compared to the 400. I am using a bolt gun, so the firing pin slamming into the primer is a non issue for me. I also had good luck with Federal GM205M primers.

[Nordy55]

Remington small rifle bench have same thickness of cups as magnums..

[Happy2Shoot]

Just to state the obvious.

CCI#450's are magnum primers; maybe the hottest SR primer. When you look over your reloading manual, notice the primer they used. You may need to reduce your maximum load by a 1/2 grain.

[grayfox]

For primers and an AR, there are 2 issues, one, cup hardness to eliminate slam fires. Two, ignition consistency. The cci41, br4, cci450, Fed 205ar, etc, all work for #1; as for #2, that’s specific to your gun... for the Grendel the large majority use the cci450, but if one of the other hard cup primers work better, by all means go for it. IMO it is more a question of which ones to avoid, like the rem6 1/2, cci400, etc. avoid those for an AR like the plague.

[empTshell]

I was only able to find CCI400 at one point and have never had an issue with them in my ARs. I am about to switch over to CCI41 as I picked up 5000 of those and know they work better for ARs. I have not tried the CCI450 yet. Will have to look for some next time at the store.

[Happy2Shoot]

Correct me if I am wrong.

I believe the CCI #41 and #450 have the same boom.

CCI #41 has decreased impact sensitivity.

[1Shot]

On YouTube Jonny's reloading he did a primer comparison using the same load but just switching up primers. He got different results between CCI #41 and CCI 450 in velocity and accuracy with that one load. You can probably do a search on YouTube and find his test. I am using CCI 450 with my Grendel loads. In the AR platform with 5.56 I have used CCI BR, 400, 450, Rem 7 1/2, Wolf SRM, Win. SR with no problems.

[Happy2Shoot]

IDK, his video was wonky. He had 400 shooting hotter than 450 on the 2nd round of powder.


CFE223


CCI #400 2685
CCI BR4 2653
CCI #41 2644
CCI #450 2614

[tdbru]

i like Rem 7 1/2 myself. as previous posters have noted, they're thicker cups. never a slam fire for me. one thing to make sure, though, if you're loading for any rifle but self cycling rifle especially is that the primers are fully seated to the bottom of the primer pocket. that puts the surface of the primer cup below the surface of the case head by a wee bit. you can feel it. this also is important to prevent slam fires. a "high" primer can slam fire even if it has the thicker cups. this also implies that you may need to clean out primer pockets of the primer ash to make sure the primer fully seats into the pocket.

-tdbru

[Popeye212]

One of the reasons I like the 450's is low SD's they seem to be more consistent.

[1Shot]

I just take it for granted that people know to NEVER drop the bolt on any free floating firing pin rifle like the AR with just a round sitting in the chamber. You are asking for a slam fire no matter which primer you use. Always feed from a magazine or a sled. This slows the bolt down as it moves forward.

[A5BLASTER]

I just take it for granted that people know to NEVER drop the bolt on any free floating firing pin rifle like the AR with just a round sitting in the chamber. You are asking for a slam fire no matter which primer you use. Always feed from a magazine or a sled. This slows the bolt down as it moves forward.

Done it that way a few thousand times now with both factory and handloads useing cci450's.

Not a single slamfire.

Could it happen? Sure. Likely hood of it happening. Slim to none.

[Klem]

I have hand loaded rounds into the chamber and dropped the bolt more times than I care to remember. The barrel is of course always pointing in a safe direction. Never had a slam fire and never seen, or even know anyone who has. I have read about it but I think we need to put it in perspective, it is almost an urban myth...almost.

I use 450's for the slam fire protection, but also because they are a consistent primer and protect against piercing and over-pressure. The small-primer guys in F Class use them when overloading their 223's to get to 1K yards. They are intensely competitive and fastidious with components. They cost no more than other primers so for me it's an easy decision.