Magnum primers for non-magnum loads

longfellow · March 5, 2012, 10:30 AM

Has anyone experimented with magnum primers in 38 Special or 357 Mag loads using Unique and cast bullets?
How comparable is velocity?
Did you see any pressure signs?
Where were you in the range of loads typically possible with Unique (Light to Medium) whe you used magnum primers?

Al57 · March 5, 2012, 11:55 AM

I know you specified cast bullets, but fwiw, I have used 7.3 grs. of Unique under a 158 gr. JHP in .357 mag with Win. mag primers. It ran about 1100 fps from 4 " bbls. . It gave fairly mild recoil and not much blast compared to beefier .357 loads, somewhat less so on both counts than my current load of 13.5 grs of 2400 ( 1150 + fps ) using the same 158 gr. JHP and standard primers. Neither load shows signs of over pressure whatsoever and fired cases are not in the least bit sticky while extracting.

Adamantium · March 5, 2012, 12:26 PM

I've used magnum primers with 38spl and 9mm and never had a problem with over pressure. That being said I treated each load as an individual and worked it up from a reduced charge. The exception would be shooting 38spl power loads in 357 brass in a 357.

longfellow · March 5, 2012, 01:16 PM

I forgot to ask those of you who have successfully substituted in Mag primers, how has this affected accuracy?

Al57, Your advice is Ironic. The very reason that I want to get through these mag primers is that, after spending a good portion of my container of H-110 and using the popular 167 gr JFP to develop a heavy load for my Blackhawk, I am left with more than a half a brick of the primers. I have completed my development, am out of H-110 which is just fine (I am in no hurry to go back to pulling the trigger on those loads) but have quite a few mag primers left which I'd perfer not to store. If I ever want to go back to making that particular load, I'll go buy a hundred count; but will likely never really need that powder or the mag primers again (Engineers do things just to learn; we're odd that way.). So I am looking to get through these primers but with my Unique and 166gr cast SWC load that has proved very accurate.

rclark · March 5, 2012, 07:31 PM

Unique is primer insensitive. All I load is cast bullets. Velocity change is only a few fps, not enough to matter according to my chrono. I can get you actual data if you wish. As far as I could tell, accuracy wasn't affected or at least not enough to matter. When I can, I use standard primers with Unique.

Note : Magnum primers have nothing to do with Magnum loads. It is all about matching the primer to the powder. Some powders like IMR 4227, H-110 require magnum primers. Some powders don't care what primer is used. Other times some powders shoot better using a Magnum primer even if not required. 2400 is primer sensitive. You get a big jump in velocity with a magnum primer which means higher pressures. So all a game. Rule of thumb is to use what the loading manual says to use (non vs magnum). Then if you are curious, use a chronograph to test regular vs. magnum ... and of course test for accuracy. Then draw your own conclusions (which is part of the 'fun'

) .

m&p45acp10+1 · March 6, 2012, 08:48 PM

I have loaded several thousand rounds of .45 acp 200 grain cast lead semiwadcutters using Bull's Eye, and CCI magnum primers. They shoot just the same as the regular ones. During the great primer shortage I ended up trading for a bunch of LPM primers. I used them no problems.

For .38 spcl I use small rifle primers with all of my loads. They shoot just fine too.

March 5, 2012, 10:30 AM	#1
longfellow Senior Member Join Date: October 11, 2010 Location: Upstate NY Posts: 144	Magnum primers for non-magnum loads Has anyone experimented with magnum primers in 38 Special or 357 Mag loads using Unique and cast bullets? How comparable is velocity? Did you see any pressure signs? Where were you in the range of loads typically possible with Unique (Light to Medium) whe you used magnum primers?

March 5, 2012, 12:26 PM	#3
Adamantium Senior Member Join Date: June 6, 1999 Location: El Paso, TX Posts: 1,021	I've used magnum primers with 38spl and 9mm and never had a problem with over pressure. That being said I treated each load as an individual and worked it up from a reduced charge. The exception would be shooting 38spl power loads in 357 brass in a 357. __________________ New gun, same ol' shot.

March 5, 2012, 01:16 PM	#4
longfellow Senior Member Join Date: October 11, 2010 Location: Upstate NY Posts: 144	How about accuracy I forgot to ask those of you who have successfully substituted in Mag primers, how has this affected accuracy? Al57, Your advice is Ironic. The very reason that I want to get through these mag primers is that, after spending a good portion of my container of H-110 and using the popular 167 gr JFP to develop a heavy load for my Blackhawk, I am left with more than a half a brick of the primers. I have completed my development, am out of H-110 which is just fine (I am in no hurry to go back to pulling the trigger on those loads) but have quite a few mag primers left which I'd perfer not to store. If I ever want to go back to making that particular load, I'll go buy a hundred count; but will likely never really need that powder or the mag primers again (Engineers do things just to learn; we're odd that way.). So I am looking to get through these primers but with my Unique and 166gr cast SWC load that has proved very accurate.

March 5, 2012, 07:31 PM	#5
rclark Senior Member Join Date: February 12, 2009 Location: Butte, MT Posts: 2,622	Unique is primer insensitive. All I load is cast bullets. Velocity change is only a few fps, not enough to matter according to my chrono. I can get you actual data if you wish. As far as I could tell, accuracy wasn't affected or at least not enough to matter. When I can, I use standard primers with Unique. Note : Magnum primers have nothing to do with Magnum loads. It is all about matching the primer to the powder. Some powders like IMR 4227, H-110 require magnum primers. Some powders don't care what primer is used. Other times some powders shoot better using a Magnum primer even if not required. 2400 is primer sensitive. You get a big jump in velocity with a magnum primer which means higher pressures. So all a game. Rule of thumb is to use what the loading manual says to use (non vs magnum). Then if you are curious, use a chronograph to test regular vs. magnum ... and of course test for accuracy. Then draw your own conclusions (which is part of the 'fun' ) . __________________ A clinger and deplorable, MAGA, and life NRA member. When guns are outlawed, only outlaws will have guns. Single Action .45 Colt (Sometimes colloquially referred to by its alias as the .45 'Long' Colt or .45LC). Don't leave home without it. That said, the .44Spec is right up their too... but the .45 Colt is still the king. Last edited by rclark; March 5, 2012 at 07:40 PM.

March 6, 2012, 08:48 PM	#6
m&p45acp10+1 Senior Member Join Date: May 3, 2009 Location: Central Texas Posts: 3,930	I have loaded several thousand rounds of .45 acp 200 grain cast lead semiwadcutters using Bull's Eye, and CCI magnum primers. They shoot just the same as the regular ones. During the great primer shortage I ended up trading for a bunch of LPM primers. I used them no problems. For .38 spcl I use small rifle primers with all of my loads. They shoot just fine too. __________________ No matter how many times you do it and nothing happens it only takes something going wrong one time to kill you.

March 5, 2012, 11:55 AM	#2
Al57 Member Join Date: December 5, 2006 Location: Nebraska Posts: 69	I know you specified cast bullets, but fwiw, I have used 7.3 grs. of Unique under a 158 gr. JHP in .357 mag with Win. mag primers. It ran about 1100 fps from 4 " bbls. . It gave fairly mild recoil and not much blast compared to beefier .357 loads, somewhat less so on both counts than my current load of 13.5 grs of 2400 ( 1150 + fps ) using the same 158 gr. JHP and standard primers. Neither load shows signs of over pressure whatsoever and fired cases are not in the least bit sticky while extracting.