Magnum/small rifle primers in 9mm?


October 14, 2003, 01:20 AM
Has anybody tried using MSP or small rifle primers with small capacity cases with a slow burning, bulky powder and lightweight bullets? (thinking bluedot/800x/longshot, 9mm 90gr)

Seems like the pressure with max loads is far below redline. Hell, they might even reduce muzzle flash by burning more powder!

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October 14, 2003, 09:31 AM
I don't see the benefit, especially in 9mm.

I am actually starting to shy away from using magnum primers in true magnum loads like .44 and .357 when using Blue Dot. Only thing I will use Mag Primers in is H110 loads. Even then, I'm getting good results using Winchester Primers in those loads. (The Large or Mag Win primers)

Jim Watson
October 14, 2003, 10:00 AM
I am loading 9mm with small pistol magnum and small rifle standard primers. Not for any ballistic advantage, just that I got a lot of them in a package sale and I do not load all that many .357s or .223s.

They DO make a difference in velocity and therefore must have increased pressure. Back off and adjust by chronograph. I ended up back at the -10% starting load, it shoots close to econoball.

Robert inOregon
October 14, 2003, 11:41 AM
Since the surface is much harder on a rifle primer, all that is gained is potentially unreliable ignition.

October 14, 2003, 12:23 PM
The case is too small to benefit from magnum primers.
The only non-magnum I use magnum primers in is 10mm.

October 14, 2003, 12:51 PM
I use WSPM primers in all of my loads except for the "hot" ones in which I use CCI 400s. The CCIs are to reduce flow from the high pressure loads.

I use WLP in all the LP primer rounds.

October 15, 2003, 02:17 PM
What manual says use small rifle primers in a pistol? Or small rifle primers in a .357? Rifle primers burn hotter and should not be used at random in pistol cases. Follow your manual religiously. They people who write them do so for a living and know what they're doing.

Jim Watson
October 15, 2003, 05:33 PM
Well, Federal used to recommend their small rifle primers for .357 magnum, before they came out with a small pistol magnum. It is no longer necessary but I don't see why it won't still work safely.

Nero Steptoe
October 15, 2003, 09:17 PM
Small rifle primers are the preferred primers for .40 Super; probably work well in 400 Cor-bon and several other handgun rounds with small primer pockets. Lots of guys use small rifle primers for 9mm reloading; I don't.

October 15, 2003, 09:19 PM
I've noticed most often degraded accuracy (CCI550, Feds, WSPM); prefer CCI500.

November 15, 2003, 03:07 PM
CAUTION: The following post includes loading data beyond currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The High Road, nor the staff of THR assume any liability for any damage or injury resulting from use of this information.

I have done incremental work ups in 9mm to see what happens with many bullets and powders.

1) The feed ramp of most 9mm pistols intrudes ~.190"
The web of most 9mm cases is ~.160"
This leaves ~.030" of thin unsupported case wall.
That is not a problem for SAAMI loads or even +P+, but with enough powder the limit can be reached.

2) Another problem is the rimless case may expand at the extractor groove and the primer fall out.

3) If the first two problems don't stop me, sometimes I get a pierced primer and want to go higher. The small magnum pistol primers are made from thicker brass [no, the brass is not harder].
When I go to the magnum primer, I must start over ~.7 gr. less powder that where I left off with the standard primer. Then with ~.3 gr. more powder [plus extra primer power] the magnum primer starts piercing.

4) The small rifle primer is the same height and diameter as small pistol primers, and does not have the dimensional differences like large rifle and pistols primers.

A society that teaches evolution as fact will breed a generation of atheists that will destroy the society. It is Darwinian.

November 15, 2003, 08:23 PM
Since the surface is much harder on a rifle primer, all that is gained is potentially unreliable ignition.

And a safety margin against pierced primers for people loading major IPSC loads. Magnum pistol or sm rifle primers are fairly common among those loading hot 9x21, 9x23 and 38 Super loads.

November 15, 2003, 10:59 PM
I've been using SRP in .40 cal and 9's (9x19, 9x21 and 9x23) since I started reloading (12 years). I never noticed any difference in accuracy or muzzle flash compared to using SPP. It is indeed, harder to detonate though.

November 17, 2003, 06:06 AM
(Re)read a 1989 article by John Lawson on small rifle primers in .355"-bores; John Ricco tested pressures between SP and SR primers; only difference was cup hardness.

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