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can I use small MAG pistol primers?

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04 July 2009, 05:09
kev5000
can I use small MAG pistol primers?
HI,

Like the post states,I am reloading 40 S+W in a glock 22,I cannot get any small primes.
The store did have small MAG pistol primers can I use them without any problems? Thanks, Kev
04 July 2009, 05:45
jeffeosso
yes, if you are using middlin loads


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04 July 2009, 06:34
bartsche
fishingsome rifles pierce these primers and with the same ammo some rifles do not; size and shape of firing pin along with spring strength.
My 12bvSS will do it almost every time my Ruger # 1 so far has not. beerroger


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05 July 2009, 00:29
El Deguello
quote:
Originally posted by kev5000:
HI,

Like the post states,I am reloading 40 S+W in a glock 22,I cannot get any small primes.
The store did have small MAG pistol primers can I use them without any problems? Thanks, Kev


Use 1/10 grain less powder.....


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06 July 2009, 21:02
Stonecreek
Use them. You won' know the difference, except for how much you paid.
07 July 2009, 08:36
Recluse
Only time I can tell much of a difference between regular and magnum primers is when I'm using faster powders like Bullseye, AA#2 or W231. I can't really tell any difference in my .44 Specials using magnum primers and 6.9 gr of AA#5.
07 July 2009, 12:26
Lost Sheep
quote:
Originally posted by kev5000:
HI,

Like the post states,I am reloading 40 S+W in a glock 22,I cannot get any small primes.
The store did have small MAG pistol primers can I use them without any problems? Thanks, Kev


Yes you can use them without any problems. You just have to make sure to head off the problems.

It is my understanding that magnum primers give a longer, stronger flame to get hard-to-ignite powders burning faster or to get fully packed cartridges well lit. (Somebody correct me if I am misinformed. I have not 100% vetted my sources, so will not guarantee this as gospel.)

Since the .40 S&W is a comparatively high pressure cartridge, you want to be cautious that you don't boost pressures higher than your cartridge cases can handle, especially since the Glocks have a cutout area in the chamber for the feed ramp. Combine that "unsupported chamber" with a higher-than-normal pressure and hit the trifecta with a cartridge case head that is thinner or softer than normal and you can get a little bulge on the rear/side of the case, making reloading those cases a little more difficult or possibly a blowout.

The advice to reduce the powder level from your normal load is a good idea. If you have a chronograph, you could compare velocities of loads with standard primers to velocities with magnum primers and get an idea of how much more pressure you are geting, or how much less powder will produce equivalent results. (Assuming equal pressures will produce equal velocities, which is not exactly true, but within the same caliber and case volume and a small range of variation is close enough.)

Having run through all the cautions I can think of, I will say that I have loaded .357 magnum with medium range loads (well, okay, light loads, but medium for 38 special) using fast powders (Bullseye and Unique mostly) and used magnum primers indiscriminantly with standard primers and seen no discernable difference whatsoever (with no chronograph, but watching how much leading I get). No flattened primers, no sticky extraction, no signs of overpressure. Same observations with my 45 ACP, 9mm and 44 Mag, too.

Short answer, go for it, but back off the powder a little and only increase if you get signs of too little velocity (failures to eject properly) or if you can clock the speed of your loads. If you have a chronograph, clock your regular loads, then develop magnum-primered loads that give the same speed. Then report back to us how much less powder it took. If you lived near me, I would let you shoot over my Chrony. I'm curious now.

Lost Sheep.
07 July 2009, 21:24
larrys
I think it has all pretty much been covered. I do it all the time.

The only thing I would add is that Lost Sheep's caution about the unsupported chamber in the Glocks only pertains to the first generation guns. My third gen Glocks are just as supported as my CZ and my BIL's XD. Glock fixed the issue about 10 years ago.


Larry

"Peace is that brief glorious moment in history, when everybody stands around reloading" -- Thomas Jefferson
08 July 2009, 23:01
Reloader
I've been using the SPMs in my 38 Special loads since the SPs are hard to find right now. They work like a champ. I just backed the charges down 2/10ths grn and everything worked fine.

Good Luck

Reloader