Home Forums Hunting & Shooting Ask The Gunwriters J B, your take on magnum and large rifle primers

John, do you follow a rule of thumb as to which primer to use in regard to powder weight?

Have you done any testing with LR primers in a "magnum" size case and found better metrics with a LR primer?

I am mostly referring to Mag primers vs LR primers and not individual brands.

Thanks

As John will probably also say when he sees your question, the type of powder matters as well as the quantity.

Gotcha. Should have included that. Thinking ball powder / Tac might work better with magnums. I have never tried Tac with magnum primers in my .308 or .358 Win but have used them in my .350 mag with TAC

As mathman mentioned, it depends on the powder as well as the case size.

There's been a bunch of research done on primers (Art Alphin's A-Square handloading manual had a bunch), and there's also good info to be had from primer manufacturers. I condensed some of this, along with other info, in my chapter on rifle primers in the first Big Book of Gun Gack.

One of the points is that not all "magnum" or "standard" primers have the same approximate "hotness."

IIRC, I've read that Winchester standard rifle primers are some of the hottest. Do any of you guys have experience or info to give me about Winchester primers? I've used mostly CCI and Federal primers. I've stocked up on my primers to do me for years in the past. I had enough to do me the past four years and used great secrecy to prevent family and others from crying out to me to save them.

I’m using standard Rem 9 1/2 behind 64 gr TAC and a 200 gr Hornady in my .350 Rem Mag XP-100 with good results, even in Iowa’s late muzzleloader season. (Pistols are legal in this season)

Traditionally double based powders were considered harder to ignite. Newer double based powders like Staball and the Alliant double based extruded powders are supposed to ignite easier.

A long time ago I was told anything over 60g with double based, and over 70g with single based should use a mag primer.

But as noted, the brand of primer makes a difference too.

They were 10-20 years ago. Don't know if they still are, since many companies (perhaps including Winchester) are having other companies make components these days, whether primers, brass or bullets.

And of course, most "Winchester" powders have been made in Florida for many years.

One of the "discoveries" I made a while back during one of the periodic primer shortages that have occurred since the Clinton administration was that Federal 215s and CCI 250s produced pretty much exactly the same results in several cartridges, both in velocity and groups. Whether that's still true I don't know, since my present lots were both purchased at least 5 years ago.

Another little piece of trivia is that Winchester has apparently never offered a "magnum" small-rifle primer. Instead their standard SR primer is a sort of compromise.

But as already noted, a lot of this stuff (along with primer dimensions) is discussed in the long chapter on primers first Big Book of Gun Gack. We still have a few dozen copies, available from www.riflesandrecipes.com. (And thanks to those who've recently ordered!)

I read an article a few years ago that the Interstate Commerce Commision (ICC) regulated ALL Inter-State shipment of explosive/flammable products AND that the packaging must comply and be suited to that particular product’s volatility. Also read that testing must be performed in labs to conclude that the packaging is appropriate to accommodate any impact, etc., etc. etc. for said product under certain conditions, like a wreck, airplane crash, blah, blah, blah.
I am sure that the Feds do not keep completely up to date with manufacturing changes just like most everything else they do, but it does give an idea as to the volatility of said propellants and explosives, i.e.primers.
Please note the packaging on Federal primers as compared to the others….

Also which brand of primer makes a difference. As most of us know, the Winchester LR primers are known to be fairly hot.