Sm Rifle Primers vs Mag Sm Pistol Primer

[Mark K]

Do any of you know how a small rifle primer cup differs in hardness/strength from a magnum small pistol primer?

I have 10k of CCI Mag SPP and am considering using them in my plinking .223 loads (22gr of 2230).

I am mostly just curious. I have tried regular SPP in this load w/o pressure signs in the primer, but........ Mostly I want to save my SRP for other loads.

Mark K.

Edited August 10, 2009 by Mark K

[ShooterSteve]

Hey Mark, Something similar to this got covered a couple months ago, so a little digging may help you find more info. A couple people had tried to load the SPP in ammo for AR rifles. Since the PP has a softer cup, and the AR has a floating firing pin with no spring to hold it off the primer when the bolt carrier goes forward, their guns were going full auto due to primer strikes by the firing pin. One thing that I don't know, is if they were magnum spp or regular spp. I know a lot of guys shoot srp's out of their pistols, especially if they are running hot loads out of a super or something, but I don't think it would be the best to reverse that and shoot the spp's out of a rifle. Of course if you have a bolt gun this would be different, but it could be bad if that ammo set around for a while and got loaded in an AR somewhere in the future by mistake. If it was me I wouldn't do it. Search around for that thread, I remember seeing a lot of good info on it.

Take Care-- Steve

[Mark K]

Thanks Steve. yeah, actually I was wanting to save my SRP for my open gun. I understand your point and appreciate your advice.

Mark K

[RiggerJJ]

I would use the Mag SPP in an open pistol without hesitation...but using them in a AR, nope. I've been using standard SPP in open pistols for years without any problems, so the Mags should work fine.

jj

[Lebayer]

I would use the Mag SPP in an open pistol without hesitation...but using them in a AR, nope. I've been using standard SPP in open pistols for years without any problems, so the Mags should work fine.

jj

Since SRP were scarce for awhile, I loaded and shot about 400 rounds of .223, using Federal Mag SP primers, will no visible effects. However, in the last round of posts on this topic, a Fed employee was quoted as warning against such practice. Even though the Mag primers are hotter, they still use the softer cup common to SPP's.

[G-ManBart]

I would use the Mag SPP in an open pistol without hesitation...but using them in a AR, nope. I've been using standard SPP in open pistols for years without any problems, so the Mags should work fine.

jj

Since SRP were scarce for awhile, I loaded and shot about 400 rounds of .223, using Federal Mag SP primers, will no visible effects. However, in the last round of posts on this topic, a Fed employee was quoted as warning against such practice. Even though the Mag primers are hotter, they still use the softer cup common to SPP's.

My experience would suggest that's not exactly true. I've tried both Federal SP and Federal SPM in the same gun (two actually) with the same load and the SP primers were quite flattened where the SPM looked perfect. Loaded back to back, no other changes. That tells me the SP must have a thinner cup, a softer cup, or both. R,

[AlamoShooter]

lat year I loaded just a few 223 rounds with CCI Small mag pistol primers = put 3 in a mag #2 doubled the next try the same thing with just 3 in the mag. I didn't try any more . Bolt and carrier was near stock Rock River.

[KellyTTE]

An excellent write up on primer wall/cup thicknesses. It only covers rifle primers, but its an interesting glimpse into some of the differences between manufacturers.

http://www.jamescalhoon.com/primers_and_pressure.php

Hope that helps.

Edited October 9, 2009 by KellyTTE

[Lebayer]

An excellent write up on primer wall/cup thicknesses. It only covers rifle primers, but its an interesting glimpse into some of the differences between manufacturers.

http://www.jamescalhoon.com/primers_and_pressure.php

Hope that helps.

Thank you for sharing the site; it's helpful. Did you note that the author lists Federal 200 primers as Small Rifle, with a cup thickness of .019? My Federal SPM primers are also designated 200. Standard Federal SR are 205, with a cup thickness of .020". He states that all Small Pistol primers have a cup thickness of .017. That means that - despite the comment made by the Federal employee in a earlier post - SPM primers are definitely thicker than standard SP primers, although slightly thinner than the 205's. Since the 205s are now available - at high cost - I'll just hold my stash of SPM in reserve but won't worry much about having to use them for .223. My load runs a 55 g MG boattail at about 3k fps.