How much more power w/magnum vs regular primers?

[Cameramonkey]

Have a conundrum. While putting things back in my reloading cabinet, I looked down at two trays of CCI primers I have left from a box. For the first time ever I noticed these were SPP magnums. I never intentionally bought magnums. I assume I somehow overlooked 8 more trays of magnums when I reloaded the last batch. (no clue which they were)

I know they will add a little oompf. But how much? It's more curiosity than anything else as I run light target loads. So I doubt I'm going to overpressure these rounds.

Any idea how much extra power I'm looking at with 9mm 147gr on top of Titegroup? (probably 3.4gr if memory serves) I'm pretty sure I've shot some just based on the odds and I dont recall feeling anything out of the ordinary.

 

[BehindBlueI's]

CCI? Probably not a measurable amount that won't be lost in natural variability of round to round over a chrono.

 

[indyblue]

No experience with this (thankfully I've been paying attention). Found this thread researching this for myself.

https://www.defensivecarry.com/threads/standard-vs-magnum-small-pistol-primers-my-experience.77799/

#1 · May 18, 2009
A little while back I picked up some Winchester Small Pistol Magnum primers since I couldn't locate and standards. I loaded up some test rounds, half with standard primers and half with magnums, same powder charges, same brass, same bullets. I didn't have any overpressure signs with any of them. Here were my results (I have purposely left out powder charge weights):

.32 S&W Long, 100 grain RNFP, Trail Boss:

Ave Std. Primer: 570fps, Std. Deviation 18.08
Ave Mag Primer: 553fps, Std. Deviation 8.13

.32 H&R Magnum, 100 grain RNFP, AA#5:

Ave Std. Primer: 749fps, Std. Deviation 32.98
Ave Mag Primer: 798fps, Std. Deviation 12.11

.38 Special, 158 grain RNL, HS-6:

Ave Std. Primer: 884fps, Std. Deviation 30.27
Ave Mag Primer: 890fps, Std. Deviation 20.86

9x19mm, 130 grain FMJ, HS-6:

Ave Std. Primer: 990fps, Std. Deviation 20.79
Ave Mag Primer: 1043fps, Std. Deviation 19.70

9x19mm, 125 grain RNL, HS-6:

Ave Std. Primer: 1116fps, Std. Deviation 17.54
Ave Mag Primer: 1122fps, Std, Deviation 13.20

The only two loads that the magnum primers made any significant difference in where the 100 grain H&R Magnum and the 130 grain FMJ 9x19mm. The magnum primers seemed to be more consistent overall, though it generally didn't represent a huge change. I tested the magnums with my standard loads and the conclusion I came to is that it is safe to use magnums in place of standards in the loads I generally use. I'd test other cartridges and charge weights before using magnums in those loadings.

I'm happy with the results and I plan to use my magnum primers for the cartridges above.

...

My theory is that the magnum primers, being slightly hotter, are causing the powder to burn more consistently and therefore making the standard deviations lower. You will notice that the more significant SD reductions occurred in the cartridges that have more air space between the powder charge and bullet. The HS6 load I use for 9x19 comes close to being a compressed load in the first place, which likely means it burns pretty uniformly with standard primers.

Since I posted this I have expanded my research (still limited to small pistol primers since I don't have any magnum LP or LR, my SR are magnums, but in the case of Wolf SRM primers that just means a harder cup, not a hotter primer). I haven't seen any results significantly different from what I posted above and I've been using almost exclusively magnum primers for SP. No excessive pressure signs, no other problems. Most of my handloads are mid-range anyway, so I have been using SP and SPM pretty much interchangeably. YMMV.

 

[Leadeye]

I don't think that magnum primers have more push, I think they just burn a little longer at the same level. That's the way it was explained to me a long time ago.

It produces more consistent ignition with some smokeless powders and I use it exclusively in BP cartridges.

 

[indyblue]

I don't think that magnum primers have more push, I think they just burn a little longer at the same level. That's the way it was explained to me a long time ago.

Partially true.

Full story:

Mysteries And Misconceptions Of The All-Important Primer - Shooting Times

By Allan Jones Most component primers have a little disk of paper between the

www.shootingtimes.com

There are two ways to make a Magnum primer — either use more of the standard chemical mix to provide a longer-burning flame or change the mix to one with more aggressive burn characteristics. Prior to 1989, CCI used the first option in Magnum Rifle primers. After that, we switched to a mix optimized for spherical propellants that produced a 24-percent increase in flame temperature and a 16-percent boost in gas volume.

 

[Paul 7.62]

Well I have used Small Rifle Primers in straight wall pistol loads and have used Magnum Small Pistol primers in standard loads. When I couldn't get primers I would make due with MSP primers and have no problems with them creating too high pressure with standard target loads. Now that said SR primers in loads for 38 super comp are developed with high pressure in mind, running in the low 40,000's psi, that is to make the compensator work better. The harder cup keeps the primer from blanking.

 

[Leadeye]

Partially true.

Full story:

Mysteries And Misconceptions Of The All-Important Primer - Shooting Times

By Allan Jones Most component primers have a little disk of paper between the

www.shootingtimes.com

I'm old so I probably got my info before 1989.

 

[BehindBlueI's]

I don't think that magnum primers have more push, I think they just burn a little longer at the same level. That's the way it was explained to me a long time ago.

It produces more consistent ignition with some smokeless powders and I use it exclusively in BP cartridges.

I believe it to be variable across both brands and different eras of manufacture.

 

[Trapper Jim]

Have a conundrum. While putting things back in my reloading cabinet, I looked down at two trays of CCI primers I have left from a box. For the first time ever I noticed these were SPP magnums. I never intentionally bought magnums. I assume I somehow overlooked 8 more trays of magnums when I reloaded the last batch. (no clue which they were)

I know they will add a little oompf. But how much? It's more curiosity than anything else as I run light target loads. So I doubt I'm going to overpressure these rounds.

Any idea how much extra power I'm looking at with 9mm 147gr on top of Titegroup? (probably 3.4gr if memory serves) I'm pretty sure I've shot some just based on the odds and I dont recall feeling anything out of the ordinary.

No end use difference.

 

[armalitesheepdog]

I have used magnum primers when I couldn’t find standard primers. Load as normal no difference whatsoever. I have even chronograph and all were within the same variance as standard primers. So load away with out worry

 

[Aszerigan]

I'm with Trapper on this one. Don't lose any sleep, just shoot them up. If you're within the proper charge range, a mag primer won't push it to anywhere near unsafe.

 

[Cameramonkey]

I'm with Trapper on this one. Don't lose any sleep, just shoot them up. If you're within the proper charge range, a mag primer won't push it to anywhere near unsafe.

Yeah, as I said in the opening post, I’m not really worried as much as I am curious. It’s not like I was loading at the top of the load data and was concerned of over pressure.

In fact, I was shooting for just over power factor limits of IDPA. So pretty much a point somewhere just below the halfway point of the load data.

 

[Aszerigan]

Yeah, as I said in the opening post, I’m not really worried as much as I am curious. It’s not like I was loading at the top of the load data and was concerned of over pressure.

In fact, I was shooting for just over power factor limits of IDPA. So pretty much a point somewhere just below the halfway point of the load data.

I've heard that mag primers can add the equivalent of 0.1-0.2gns of powder charge, but I've never proven this, nor have I seen a difference in velocity using standard primers in mag loads nor vice versa.

 

[mdunn]

Have a conundrum. While putting things back in my reloading cabinet, I looked down at two trays of CCI primers I have left from a box. For the first time ever I noticed these were SPP magnums. I never intentionally bought magnums. I assume I somehow overlooked 8 more trays of magnums when I reloaded the last batch. (no clue which they were)

I know they will add a little oompf. But how much? It's more curiosity than anything else as I run light target loads. So I doubt I'm going to overpressure these rounds.

Any idea how much extra power I'm looking at with 9mm 147gr on top of Titegroup? (probably 3.4gr if memory serves) I'm pretty sure I've shot some just based on the odds and I dont recall feeling anything out of the ordinary.

I remember watching a YouTube video comparing std vs mag small pistol primers a few years ago when both were almost impossible to find and I believe it was done by Super Vel ammunition. They showed a very negligible difference in 9mm ammunition using identical components. The only comparison in primers that I personally did was using Winchester LP primers vs CCI Magnum LP primers in 44 magnum. I did not have a chronograph to check velocities but using my Thompson Center contender with a super 14 44 magnum barrel at 25 yards my groups with the Winchester primer grouped poorly and with the CCI magnum primer all five holes were touching.

 

[DadSmith]

I've heard that mag primers can add the equivalent of 0.1-0.2gns of powder charge, but I've never proven this, nor have I seen a difference in velocity using standard primers in mag loads nor vice versa.

Was coming to post this.
In rifles years ago i knew of some who actually used magnum rifle primers over match primers. They said they were getting the same reliability, and consistency from them as with match primers.
In pistols I've found no difference in velocity between spp and mspp. I can't even say one is better than the other. With loads under 20gr that is.

 

[Creedmoor]

All the decades my grand father and father reloaded, they bought two kinds of primers. Large and small.
This was never a issue before the internet.

 

[Aszerigan]

This was never an issue before the internet.

A blanket statement for life these days.

 

[SSE]

With mild loads you would be fine.
Years ago I was loading a really hot 90 gr. HP 9mm load for a customer and he wanted me to try the mag primers so I did. Bad idea! Case bulge, flat primer, ect. it sent pressures way too high.

 

[Aszerigan]

With mild loads you would be fine.
Years ago I was loading a really hot 90 gr. HP 9mm load for a customer and he wanted me to try the mag primers so I did. Bad idea! Case bulge, flat primer, ect. it sent pressures way too high.

From using a mag primer? Sounds like that load might have been a little too spicy to begin with.

Was it normal pressure with a standard primer?

 

[Creedmoor]

From using a mag primer? Sounds like that load might have been a little too spicy to begin with.

Was it normal pressure with a standard primer?

Yepper...