Virginia Gun Owners Forum - VGOF

What are your opinions on substituting magnum primers for standard, when one can't get his hands on standards? Is the primer pellet larger or is it just the strength of the cup, to handle magnum pressures?

.45ACP - Thanks in advance,
Glen

I did this using Federal large pistol magnum primers for .45 loads when there were no standard primers to be found. Without a chronograph there was no way to accurately tell what was going on except for “felt recoil and blast”. Using the magnums definitely raised pressures based on the effects of firing especially through the G36. I started with minimum loads and working up settled on a decent combination but not as accurate as the standard primer loads with 230 gr. FMJ or 200 gr. LSWC. At no point was a max load for powder used. The felt recoil and blast was enough to caution not to go much beyond minimum recommendations in Lyman or Sierra manuals. There were no overpressure signs on the cartridge case or primer.
I’d do it again given a lack of standard primers but would buy a chrony to get a better feel for what was happening.

Magnum primers are hotter than standard so reduce your load by 10 percent and then check for signs of excessive pressure.

Howdy, y'all

I've noticed some of the mfgrs. are calling their magnum primers "premium" primers, saying that they provide more reliable ignition. The implication is, at least in my mind, is that the primers are supposed to be better, but not different. Are they minimizing safety issues while trying to encourage people to substitute more expensive but available primers for the hard to find ones?

Regards,

George

I have spoken with a friend in the past that was a engineer in the CCI plant and he said that Magnum Primers have a hotter flame front to make sure that all powder is consumed in Magnum loads. I would use caution and do as Vahunter said and reduce by at least 10% and watch for pressure signs.
Bill

IF the pressure is too much, could it damage the gun? I R total n00b at reloading.

MuShuGordon wrote:IF the pressure is too much, could it damage the gun? I R total n00b at reloading.

HELL YES.

Pistol cartridges are some of the more sensitive to reload.

many of the auto loaders are only using 4-8gr of powder so being off a few tenths can matter alot more than a rifle using 40-50 gr.

Bullet seating depth has a major impact on pressures.

In regard to substituting mag for std. No you can't just swap them. If you want to start at minimum load from a reliable load book and 'work up' a new load based on your component changes then yes it would be fine. But you always work up new loads when you change components right?

jdonovan wrote:

MuShuGordon wrote:IF the pressure is too much, could it damage the gun? I R total n00b at reloading.

HELL YES.

Pistol cartridges are some of the more sensitive to reload.

many of the auto loaders are only using 4-8gr of powder so being off a few tenths can matter alot more than a rifle using 40-50 gr.

Bullet seating depth has a major impact on pressures.

In regard to substituting mag for std. No you can't just swap them. If you want to start at minimum load from a reliable load book and 'work up' a new load based on your component changes then yes it would be fine. But you always work up new loads when you change components right?

If you are not an experienced reloader I would not recommend using any data not clearly listed in an accepted load manual. You wont find any where in one of those mag primers are substituted for regular. If you are experienced then Bill and Henry gave some excellent advice.

jdonovan wrote:

MuShuGordon wrote:IF the pressure is too much, could it damage the gun? I R total n00b at reloading.

HELL YES.

Pistol cartridges are some of the more sensitive to reload.

many of the auto loaders are only using 4-8gr of powder so being off a few tenths can matter alot more than a rifle using 40-50 gr.

Bullet seating depth has a major impact on pressures.

In regard to substituting mag for std. No you can't just swap them. If you want to start at minimum load from a reliable load book and 'work up' a new load based on your component changes then yes it would be fine. But you always work up new loads when you change components right?

Yes, always work up... that's part of the fun. Plus single shots, careful case inspections and over a Chrony Beta.
... always slightly apprehensive...

The only thing a chrony will tell you is speed. The best tell tale sign is flattened or punctured primers. When you see one of those signs back off the load or next one could be the last for either you or the gun, maybe both.

Understood, which leads me to the next question... If +p pressures don't damage cases or adversely affect primers/pockets, how would you know if you were spiking high pressure?... I don't even want to approach +p pressure. Seems like a lot of seat of the pants flyin' to me.

Palladin wrote:If +p pressures don't damage cases or adversely affect primers/pockets, how would you know if you were spiking high pressure?... I don't even want to approach +p pressure. Seems like a lot of seat of the pants flyin' to me.

If you are not damaging cases/flattening primers/getting primer flow/tattooing/hard extraction then you shouldn't be spiking high pressures.

A reputable load manual will have loads that adhere to SAMMI specifications in test barrels. As long as you are not seeing pressure signs in your gun then generally the load should be reasonably safe.

With out some fancy gadgetry to measure chamber pressures you kind of need to treat the pressure as a 'black box' problem with only a yes/no answer. Either your following established loads from a reputable company and seeing no overpressure signs and therefore in the safe zone, or you are not.

Yes you can follow the loading manuals but be sure that they are modern one's. I have several that are rather old (shut up Henry) and that list loads that are higher in powder content then the new manuals.

Watch your primers they will tell you if you are on dangerous ground with flow back and or burst primers and flatend primers. Make sure that you have good load data marked down so that you can move foreward or backwards on the next load that you make.

I spent about 2 day's putting together a load for Henry's .308 Remington that would shoot into a 1/4" at 100 yards several years ago and he still loads the same load today. Take your time and be carefull and the end result is well worth it.
Bill

Solid advice all - Thank you!
I guess to rephrase my question (which y'all have already answered) - if by deviating from published data by putting mag primers in .45acp could the stronger primer possibly hide high pressures that would have been shown in a standard primer... (thinking aloud).

NO
Bill

Now you guys make me want to cook up a batch of reloads for myself. Too bad I don't have anything but some 270 casings that I have been saving.

Palladin wrote:Solid advice all - Thank you!
I guess to rephrase my question (which y'all have already answered) - if by deviating from published data by putting mag primers in .45acp could the stronger primer possibly hide high pressures that would have been shown in a standard primer... (thinking aloud).

Possibly, but reasonably unlikely.

The 'magnum' primers in general have thicker cups. Therefore it generally takes more pressure before the magnum primer will show pressure signs.

http://www.jamescalhoon.com/primers_and_pressure.php


The 45acp is a reasonably low pressure pistol cartridge. Even at 45acp+ (23,000 psi) I doubt you'd see pressure signs until you were SERIOUSLY over pressure.

Take the 40S&W which uses the same primer, and runs at 32K PSI vs the standard 45acp at 21K PSI. If the 40S&W should not show over pressure at 32k, that would mean your 45ACP could be 50% over pressure and still be operating in the 'normal' range for the same primer in a different case.


So going back to the question that opened this discussion.... can you use magnums where standards are called for. My vote is a qualified yes.

Qualified by don't try to run top end or +p level loads. Start your work up again from the minimum load listed in current, reputable loading manuals, and as always watch for over pressure signs.