mag primers in 40s&w

[longshot7.62x51]

I am trying to see if there is a formula for use small mag pistol primers in a 40 s&w how much I have to load down the powder charge I order to use them. I have read just drop the load by 1 gr. But would like some more input. Thank you in advance
longshot

 

[MtnCreek]

What powder are you using. Longshot?

 

[longshot7.62x51]

Imr sr7526

 

[longshot7.62x51]

Imr sr7625

 

[MtnCreek]

I'm going to step aside and let someone w/ exp w/ 7625 & 40sw help.

 

[jim243]

There is not a lot of room for error in loading for the 40 S&W. It has been some time since I have loaded for them and I am not familuar with that powder.

Depending on who's primers we are talking about, Winchester, CCI, Federal, Wolf, ETC...

I would say 1 grain under max and work your way back up checking for over pressure after each shot should keep you safe. What your results will be is anyones guess.

I would normally tell you to just get standard pistol primers, but in todays conditions that might be hard to do. So start at the min charge for that powder for weight and type of bullet and go slow in bring it up.

Good luck and stay safe.
Jim

 

[longshot7.62x51]

Thanks for the Intel. I will prob crank some out this weekend

 

[jerkface11]

You're starting over so start at the starting load. It's a high strung cartridge best to play it safe.

 

[FROGO207]

I would only try a few at first. Your handgun might not be able to fire the primers due to the cup being much thicker. A test with the primers would be a first step IMHO. Otherwise a 1 grain drop and work back up would be what I would do also. These trying times allow us the latitude to "try" other than the standard options and I feel this is a good thing.

 

[longshot7.62x51]

The pistol I will using is a Sig 2022 with Fed primers. The plan is to use the starting load (I don't usually go much higher with my pistol ammo anyway) and work it in a 5rd batch for testing. Frogo I agree with trying New things the current shortages have given me many ideas I'm also starting a black powder45 acp load and hopefully working on making my own powder (black) for that load at some point

 

[gamestalker]

The .40 cal. is an inherently high pressure pistol cartridge to begin with, so using magnum primers is probably not the best idea. I know it can be and is done by many without circumstance, though I recently had thoughts of trying it myself, I had a change of heart and decided to just use my short supply of standard primers. I suppose if you are using a starting charge that produces pressures at the lower end of the spectrum for .40 cal, you wouldn't have much to be concerned about. So the advice here is, use starting charges and work up as you would when introducing any new component.

GS

 

[zxcvbob]

I'm not familiar with IMR SR7625, but in general SPM or SR primers will work just fine. With some powders (like HS-6) they will even work better than SP's. HOWEVER, you need to start all over at a minimum load (generally 10% below max) and work it up again when you switch to a hotter primer.

 

[Muddydogs]

All I load is mag primers so thats what I load for the .40. Just work up the load and all will be fine. Some brands of mag primers are hotter then others but we are not talking a hole lot of difference between mag and standard primers. The saying use to be that a mag primer was the same as an extra grain of powder but I don't know if thats still true or not.

 

[GLOOB]

Mag primers work fine in 40SW, and I seriously doubt you have to back off a full grain of any common powder. Remington doesn't mark "magnum" on their primers, but they advise the use of the 5 1/2 "magnum primer" in 357 mag and 40SW, specifically. And the 1 1/2 for other non-magnum small pistol primer calibers.

This has as much to do with pressure as it does case volume or hard-to-ignite powders. High pressure calibers can pierce primers if the cups are too soft. 40SW and 9mm para pressure is high enough to seal harder magnum primer cups. You might get better accuracy, ESD, or velocity using one or the other, depending on your load, but there's no real reason not to use SPMs, unless you're running light pressures using cast bullets. At lower pressures, some mag primers might not seal in looser pockets, which can lead to gas cutting on the breechface.

 

[ArchAngelCD]

Magnum primers will burn a little longer and a little hotter than standard primers. They will no induce a nuclear explosion. In most cases you will be able to generate the same velocities with a magnum primer over a standard primer with .1gr or .2gr lower on the charge, no more.

Like any time you change components drop the charge weights back and work up the load.

 

[James2]

The age old standing advice is: If you change anything, start low and work up.

Sorry, I don't load for 40 so no specifics.

 

[frankge]

I have loaded .40 for USPSA major PF using federal magnum match with
4.5 titegroup and now 4.7. could not really tell difference shooting or on chrono.