Why Magnum primers?

[glocker21]

Only slam fire I have ever had was with the M1 Garand many years ago when I first got one and started hand loading for. It doubled once and then with the next clip it tripled. Experienced M1 person at range stopped me and before I could tell him what primer I was using he said I bet you are using Federal primers. Sure enough I was using Federal. 210 Match. He as well as others in the high power game have told me that the only primer that they have seen slam fire that was seated correctly has been Federal. Federal now makes a AR specific small rifle primer. Only slam fire I have ever witnessed with an AR was when a fellow was trying to use Remington 6 1/2. I have used many Remington 7 1/2 with no problems. As I said I have never had any problems with any primer except Federal. On Jonny's Loading Bench on YouTube he did a primer comparison video using just one load and there was a difference in what primer was used but not that much with some. Now that was with ONE load. If you change the load things might be difference. Go to YouTube and check this out. I used CCI 450 with all my Grendel loads because that is what I started working with and what I found my loads with.

Great Info! Thanks

[glocker21]

Factory Hornady with the brass colored primers have cratered and ruptured in my Grendels. Handloads with the CCI 450s never have had an issue with the same bullet weights as factory.

Great info!

[centerfire]

Factory Hornady with the brass colored primers have cratered and ruptured in my Grendels. Handloads with the CCI 450s never have had an issue with the same bullet weights as factory.

Have you considered replacing your bolt and firing pin? That isn't generally a primer issue.

[centerfire]

I've chronographed load combinations with standard and magnum primers and never seen the pressure spikes some people claim happen with magnum primers. Further, I can't find much difference between CCI 400, 450, and Federal 205. No slam fires, no pressure changes, and no real performance differences. 223 Remington or 6.5G, it doesn't seem to matter.

A few weeks ago I ran some hot 223 Remington loads with BR4, 41, 400, 450, 500 (Pistol), 550 (Pistol), and 205. The goal was to see if I could take a load with a high extreme spread and lower it. The groups with magnum primers were identical to non magnum rifle primers. The pistol primers were slightly slower. My medical bills remained unchanged as did my gunsmithing bills.

[Mesa1978]

Have you considered replacing your bolt and firing pin? That isn't generally a primer issue.

Shilen barrel with fitted/numbered AA bolt, Smith chrome, not DPMS, BCG and Colt FP. Hornady factory silver primers were fine from the same box of 20, brass colored factory primers had the issues, replaced FP with another Colt due to factory ammo failures. Never an issue with handloads in the gun. No issues with other factory ammo, just Hornady brass colored primers. Go/No Go gauges on assembly used and verified for headspace.

[VASCAR2]