Small primer question

joneb · July 14, 2007, 07:10 PM

I'm wondering what the differences are between small magnum pistol and small rifle primers ?
Someone from another forum had higher velocities with small pistol magnum than small rifle for .45 acp NT. I thought it would be the other way around

So which is the hotter primer ? thanks jj

crowbeaner · July 14, 2007, 09:37 PM

Small rifle primers have a thicker cup and require a harder firing pin strike to ignite. They are also designed to operate at much higher chamber pressures than pistol primers, so DO NOT substitute rifle primers for pistol, and vice versa. As far as brisance (how "hot") they are, I haven't seen a listing of "coldest to hottest" primers published. Perhaps a more knowledgeable reader will know of a listing you can obtain. If you do find one I'd like to copy it for myself. CB

Trapper L · July 14, 2007, 11:20 PM

In addition to crowbeaners comments, the mag primer will be a hotter flame front and a longer burn time. You can use pistol primers in rifle cartridges providing that you are aware of the pressures of that particular cartridge. I use small pistol primers in all of my 30 Carbines. I get fabulous accuracy using them over what is achievable with even the benchrest rifle primers. But the 30 Carbine is not a high pressure case so there is no issue doing it. Using a small pistol primer on a max load in a 223 would be a recipe for injury. So if you have to ask about mixing primers across the rifle/pistol line, it's best you don't do it.

amamnn · July 15, 2007, 01:21 AM

As noted above, it is not advisable to substitute primers designed for one purpose in a cartridge designed for another purpose. That being said, many of us have been tempted and in fact have used rifle primers in handgun loads and vice versa because of the the primer shortage. I have seen some failures due to this recently, though none were catastrophic. Some folks have used rifle primers in handgun loads and seen reduced performance. This is not surprising since the rifle primers have a thicker cup and we all know, or should know, that primer efficiency is directly related to the relationship of the cup/anvil pressure generated by the firing pin or hammer.

I 've seen a couple failures to fire in rifle loads due to the pistol primer used being blanked. In one case the primer was pierced and the charge of the primer was directed backward and the powder was not ignited. In the other case the cup of the pistol primer was destroyed; the powder was partially ignited and the bullet lodged in the barrel of the rifle. Luckily, the shooter recognized the sound of a squib and did not load another round.

July 14, 2007, 07:10 PM	#1
joneb Senior Member Join Date: December 10, 2005 Location: Central , OR Posts: 1,888	Small primer question I'm wondering what the differences are between small magnum pistol and small rifle primers ? Someone from another forum had higher velocities with small pistol magnum than small rifle for .45 acp NT. I thought it would be the other way around So which is the hotter primer ? thanks jj

July 14, 2007, 09:37 PM	#2
crowbeaner Senior Member Join Date: June 4, 2007 Location: Upstate SC Posts: 1,943	Small rifle primers have a thicker cup and require a harder firing pin strike to ignite. They are also designed to operate at much higher chamber pressures than pistol primers, so DO NOT substitute rifle primers for pistol, and vice versa. As far as brisance (how "hot") they are, I haven't seen a listing of "coldest to hottest" primers published. Perhaps a more knowledgeable reader will know of a listing you can obtain. If you do find one I'd like to copy it for myself. CB

July 14, 2007, 11:20 PM	#3
Trapper L Senior Member Join Date: November 20, 2006 Location: South Texas Posts: 804	In addition to crowbeaners comments, the mag primer will be a hotter flame front and a longer burn time. You can use pistol primers in rifle cartridges providing that you are aware of the pressures of that particular cartridge. I use small pistol primers in all of my 30 Carbines. I get fabulous accuracy using them over what is achievable with even the benchrest rifle primers. But the 30 Carbine is not a high pressure case so there is no issue doing it. Using a small pistol primer on a max load in a 223 would be a recipe for injury. So if you have to ask about mixing primers across the rifle/pistol line, it's best you don't do it.

July 15, 2007, 01:21 AM	#4
amamnn Senior Member Join Date: May 13, 2006 Location: WA, the left armpit of the USA Posts: 1,323	As noted above, it is not advisable to substitute primers designed for one purpose in a cartridge designed for another purpose. That being said, many of us have been tempted and in fact have used rifle primers in handgun loads and vice versa because of the the primer shortage. I have seen some failures due to this recently, though none were catastrophic. Some folks have used rifle primers in handgun loads and seen reduced performance. This is not surprising since the rifle primers have a thicker cup and we all know, or should know, that primer efficiency is directly related to the relationship of the cup/anvil pressure generated by the firing pin or hammer. I 've seen a couple failures to fire in rifle loads due to the pistol primer used being blanked. In one case the primer was pierced and the charge of the primer was directed backward and the powder was not ignited. In the other case the cup of the pistol primer was destroyed; the powder was partially ignited and the bullet lodged in the barrel of the rifle. Luckily, the shooter recognized the sound of a squib and did not load another round.