Small pistol magnum primers in .40s&w

Smogdude · May 12, 2009, 06:12 PM

Happened by a gun store today and lo and behold they had a few hundred small pistol magnum primers.. so I picked up a 100 pack. From what I've read regarding the use of SPMP in loads that don't call for it, you can generally compensate for pressure increase by decreasing your starting charge by 5%.

How many of you have subbed mag primers in a pinch and been ok by slight decrease in charge?

howlnmad · May 12, 2009, 06:56 PM

I ain't touching that one cuz I stick to the books. Good luck

.

troy_mclure · May 12, 2009, 08:04 PM

i plan on doing it for my xd40sc, and keltec p32.

ive already fired quite a few .40s&w loaded with small rifle.

Smogdude · May 12, 2009, 08:17 PM

I just loaded 5 test cartridges, three with federal brass, two with magtech, using CCI 550 small pistol mag primers, 6gns of AA#5 behind a 180gn gold dot hp. All have an OAL between 1.125" and 1.135". Plan on testing them with my sig p226.

That'll Do · May 12, 2009, 08:58 PM

Well, I haven't tried using the small mag primers in 40 S&W yet, but I have used them successfully (and safely) in 9mm Luger.

I reduced my charge by about 5% and then worked back up. So far, so good.

Shoney · May 12, 2009, 09:24 PM

I've experimented with them in 40SW. The 5% reduction below start may be a bit much, especially when your regular start load is 3.0 grains. I believe you can start at the min listed load and work up, I did, staying 3-5% below max. Most of my accuracy loads with mag primers using 10-12 different powders were in the mid load ranges anyway.

madmo44mag · May 12, 2009, 10:25 PM

[QUOTE]S I've experimented with them in 40SW. The 5% reduction below start may be a bit much, especially when your regular start load is 3.0 grains. I believe you can start at the min listed load and work up, I did, staying 3-5% below max. Most of my accuracy loads with mag primers using 10-12 different powders were in the mid load ranges anyway. /QUOTE]

+1

I do it from time to time when STD primers can't be found.
The only cartridge that does not respond well with the mag primer is the 45acp.
It works but accuracy suffers and so does the gun.

tiberius10721 · May 12, 2009, 10:33 PM

ive used magnum primers plenty of times but then again i always use starting loads for my 38 special and 45acp.

fatboy02 · May 12, 2009, 10:33 PM

I am new to reloading but, I had to use the mag primers too and there was no noticable difference but I load middle of the road. I am no where near max.

BillM · May 12, 2009, 10:40 PM

I use them in everything. Mousefart 9mm, minor PF 40, 40 major and
9mm major. You will see maybe 15 FPS more velocity. In my old
40 minor Production division load the better ignition also made the
velocity much more consistent. If you are running a max load, back
off a bit and work up when you change ANY component---even when
you change lot numbers on powder.

bullspotter · May 12, 2009, 11:35 PM

Hey Madmo44, can you please explain what they do to accuracy and the gun?? Your Quoted below.........

I do it from time to time when STD primers can't be found.
The only cartridge that does not respond well with the mag primer is the 45acp.
It works but accuracy suffers and so does the gun.

Smogdude · May 12, 2009, 11:46 PM

Thanks for the responses.. I also pulled a centurion M193 cartridge this evening that had been jammed in the bolt of my AR15 and colapsed the case at the shoulder. The jam was due to bent feed lips on an old magazine. Anyhow pulled the bullet and checked the powder charge.. 23.3 grains of some chunky stuff.. but this is a fairly hot charge. I deprimed carefully and reprimed a LC 08 case and charged with 23.4 grains of AA 2230 behind a barnes .224" 50grain varmint grenade. I put the 23.3 grains of centurion powder in a seperate container.

So even though I don't have any small rifle primers.. I managed to salvage one out of a damaged round.

That'll Do · May 13, 2009, 03:24 PM

Quote:

Originally Posted by Shoney

I've experimented with them in 40SW. The 5% reduction below start may be a bit much, especially when your regular start load is 3.0 grains. I believe you can start at the min listed load and work up, I did, staying 3-5% below max. Most of my accuracy loads with mag primers using 10-12 different powders were in the mid load ranges anyway.

I should've elaborated more–if someone is starting from scratch, and working a load up from the starting charge, then I agree that 5% is excessive. They should just start at the recommended starting charge. The load I was using was in the upper mid-range, so that's why I backed off the charge 5%.

But I agree that if you're at the starting charge, no further reductions are needed when using magnum instead of standard primers.

Smogdude · May 13, 2009, 10:26 PM

Quote:

I should've elaborated more–if someone is starting from scratch, and working a load up from the starting charge, then I agree that 5% is excessive. They should just start at the recommended starting charge. The load I was using was in the upper mid-range, so that's why I backed off the charge 5%.

But I agree that if you're at the starting charge, no further reductions are needed when using magnum instead of standard

Ok so If I decreased my starting charge of AA#5 from 6.3gns to 6.0.. will I suffer from a squib or the action not cycling properly? I planned on taking the barrel out of the gun after the first round just to double check.

That'll Do · May 14, 2009, 09:54 AM

Quote:

Originally Posted by Smogdude

Ok so If I decreased my starting charge of AA#5 from 6.3gns to 6.0.. will I suffer from a squib or the action not cycling properly? I planned on taking the barrel out of the gun after the first round just to double check.

It's not that you're guaranteed to have a squib or have the action not cycle properly, it's that there is the possibility it could occur.

If your reloading manual states a starting charge of 6.3gr, then start there.

The reason I decreased my charge was because I already had a load I liked, but it was above the recommended starting charge. Anytime you change a component, you should reduce your charge and work back up, watching for signs of pressure.

madmo44mag · May 14, 2009, 10:50 AM

Quote:

Hey Madmo44, can you please explain what they do to accuracy and the gun?? Your Quoted below.........

I do it from time to time when STD primers can't be found.
The only cartridge that does not respond well with the mag primer is the 45acp.
It works but accuracy suffers and so does the gun.
bullspotter is offline Report Post

The 45 acp is a low psi round. If loaded near or at max, psi go way up with the mad primer.
This beats the rails and stops on the gun unnecessary hard.
Also due to it being a low psi round the powder ignites and burns erratically fast due to the hotter ignition source.
The only time I ever get decent results in the 45acp with mag primers is when I load at the very bottom of the load range and it's still not as good as when loaded with STD primers.
Someone may come along and dispute this and that's fine. All I am is stating what I have learned from many years of reloading.

May 12, 2009, 06:12 PM	#1
Smogdude Member Join Date: October 6, 2008 Location: Dublin CA Posts: 57	Small pistol magnum primers in .40s&w Happened by a gun store today and lo and behold they had a few hundred small pistol magnum primers.. so I picked up a 100 pack. From what I've read regarding the use of SPMP in loads that don't call for it, you can generally compensate for pressure increase by decreasing your starting charge by 5%. How many of you have subbed mag primers in a pinch and been ok by slight decrease in charge?

May 12, 2009, 08:04 PM	#3
troy_mclure Senior Member Join Date: November 17, 2008 Location: gulf of mexico Posts: 2,716	i plan on doing it for my xd40sc, and keltec p32. ive already fired quite a few .40s&w loaded with small rifle. __________________ There is only one tactical principle which is not subject to change. It is to use the means at hand to inflict the maximum amount of wound, death, and destruction on the enemy in the minimum amount of time."

May 12, 2009, 09:24 PM	#6
Shoney Senior Member Join Date: February 21, 2002 Location: Transplanted from Montana Posts: 2,311	I've experimented with them in 40SW. The 5% reduction below start may be a bit much, especially when your regular start load is 3.0 grains. I believe you can start at the min listed load and work up, I did, staying 3-5% below max. Most of my accuracy loads with mag primers using 10-12 different powders were in the mid load ranges anyway. __________________ I pledge allegiance to the Flag - - -, and to the Republic for which it stands….Our Forefathers were brilliant for giving us a Republic, not a democracy! Do you know the difference??? and WHY?http://www.wallbuilders.com/LIBissue...les.asp?id=111

May 12, 2009, 10:25 PM	#7
madmo44mag Senior Member Join Date: December 29, 2008 Location: Ft.Worth, Texas Posts: 1,522	[QUOTE]S I've experimented with them in 40SW. The 5% reduction below start may be a bit much, especially when your regular start load is 3.0 grains. I believe you can start at the min listed load and work up, I did, staying 3-5% below max. Most of my accuracy loads with mag primers using 10-12 different powders were in the mid load ranges anyway. /QUOTE] +1 I do it from time to time when STD primers can't be found. The only cartridge that does not respond well with the mag primer is the 45acp. It works but accuracy suffers and so does the gun. __________________ Texas - Not just a state but an attitude! For monthly shooting events in DFW visit http://www.meetup.com/TexasGunOwner-DFW

May 12, 2009, 06:56 PM	#2
howlnmad Senior Member Join Date: April 29, 2009 Location: Harriman Tn Posts: 424	I ain't touching that one cuz I stick to the books. Good luck .

May 12, 2009, 08:17 PM	#4
Smogdude Member Join Date: October 6, 2008 Location: Dublin CA Posts: 57	I just loaded 5 test cartridges, three with federal brass, two with magtech, using CCI 550 small pistol mag primers, 6gns of AA#5 behind a 180gn gold dot hp. All have an OAL between 1.125" and 1.135". Plan on testing them with my sig p226.

May 12, 2009, 08:58 PM	#5
That'll Do Senior Member Join Date: October 25, 2008 Location: Pittsburgh, PA Posts: 546	Well, I haven't tried using the small mag primers in 40 S&W yet, but I have used them successfully (and safely) in 9mm Luger. I reduced my charge by about 5% and then worked back up. So far, so good.

May 12, 2009, 10:33 PM	#8
tiberius10721 Junior member Join Date: December 22, 2008 Posts: 228	ive used magnum primers plenty of times but then again i always use starting loads for my 38 special and 45acp.

May 12, 2009, 10:33 PM	#9
fatboy02 Senior Member Join Date: November 27, 2005 Location: Olivet, MI Posts: 163	I am new to reloading but, I had to use the mag primers too and there was no noticable difference but I load middle of the road. I am no where near max.

May 12, 2009, 10:40 PM	#10
BillM Senior Member Join Date: January 20, 2009 Location: Amity Oregon Posts: 791	I use them in everything. Mousefart 9mm, minor PF 40, 40 major and 9mm major. You will see maybe 15 FPS more velocity. In my old 40 minor Production division load the better ignition also made the velocity much more consistent. If you are running a max load, back off a bit and work up when you change ANY component---even when you change lot numbers on powder.

May 12, 2009, 11:35 PM	#11
bullspotter Senior Member Join Date: November 2, 2008 Location: Montana Posts: 308	Hey Madmo44, can you please explain what they do to accuracy and the gun?? Your Quoted below......... I do it from time to time when STD primers can't be found. The only cartridge that does not respond well with the mag primer is the 45acp. It works but accuracy suffers and so does the gun.

May 12, 2009, 11:46 PM	#12
Smogdude Member Join Date: October 6, 2008 Location: Dublin CA Posts: 57	Thanks for the responses.. I also pulled a centurion M193 cartridge this evening that had been jammed in the bolt of my AR15 and colapsed the case at the shoulder. The jam was due to bent feed lips on an old magazine. Anyhow pulled the bullet and checked the powder charge.. 23.3 grains of some chunky stuff.. but this is a fairly hot charge. I deprimed carefully and reprimed a LC 08 case and charged with 23.4 grains of AA 2230 behind a barnes .224" 50grain varmint grenade. I put the 23.3 grains of centurion powder in a seperate container. So even though I don't have any small rifle primers.. I managed to salvage one out of a damaged round.