Primers

[Gunforall]

I have a friend that also reloads and he tells me i can use magnum primers in my 45ACP. I know they fit in the pocket but is this safe? And if so do i change up my powder charge.

[jaguarxk120]

Just because they fit is not good reasoning to use them. Magnum primers have a lot more mixture than standard ones. Thats so they can ignite more powder in a larger magnum case. Look at the size differences between the 45ACP and a 44 Magnum. Even with bullets seated the case volumn is 2 - 2 1/2 times greater in a magnum case.

If you choose to used them your pressures will go way up because of the added priming mix. Not a good idea.

[Shoney]

Yes! Magnum primers (Large pistol) can be used safely in 45ACP if you either:

1. start at minimum charge weight and work up; or
2. drop your pet load 2 grains lower and work up

I have substituted Magnum primers in many pistol and rifle cartridges, always starting at minimum charge weights and working up carefully.

[T. O'Heir]

Magnum primers are about the powder used. They burn a bit hotter for a bit longer. They're made to light hard to ignite powders and cold weather shooting. You only need 'em if your manual says to use 'em.
Like Shoney says, you can use 'em, but you don't need 'em for typical .45 ACP powders.
"...have a lot more mixture..." Nope. Just a different compound.
"...in a magnum case..." You don't need 'em for .44 Mag loads either. The name of the cartridge has nothing to do with it. Strictly the powder used.
If you change any one component, you need to work up the load again.

[SKULLANDCROSSBONES65]

G'day. This article might help explain things.

[scottrussell]

I have started loading for my redhawk 44 mag 7.5 inch barrel. have been using cci 300 primers with H110 powder. I believe it nessesary to move to a magnum primer and my question alone that line is...cci 350 or WLP and is there a significant differance ?

[Yoosta B. Blue]

My daughter gave me 2K of of Wolf LP Magnum primers as a gift last Christmas. I had never used any Magnum primers, so I reduced the charge weight in my .45 loads a little, and did some testing. I ended up working back up to the exact same charge weight that I used before. I can detect no difference.

YBB

[dahermit]

...I have a friend that also reloads and he tells me i can use magnum primers in my...

Good sources for hand loading data: Powder companies, Hand loading manuals. The fool's choice: Bar patron's, friends.

[Unclenick]

Military ammunition is all made with magnum primers or their equivalent. This is to ensure consistent ignition in extremely low temperatures. Therefore, you may conclude that there are few situations in which they may not be substituted, provided you work the load back up.

There is no generic relationship between magnum primers and pressure change. How primers are compounded changes over time. Some magnum primers have been made by simply increasing the size of the pellets, but I believe most are done by leaving the net level of the sensitizing lead styphnate alone while increasing the portion of fuel compound to make more gas. This lowers the brissance of the mix from that of its standard counterpart. The primer companies have changed these mixtures and the thickness of the primer cups over the years, and they don't announce these alterations with any great fanfare. So, you need to be aware that each new lot of primers you get has a chance of being different from the last.

QuickLOAD's author, in its manual, points out that the result of the above is that while magnum primers usually raise start pressures, there are situations in which they can actually lower them, as well. I see that most often short pistol cases firing lead bullets, because the magnum primer unseats the bullet before the powder burn gets very far. That increases the volume the powder is burning it, lowering pressure. It's not a very consistent effect, so if using a magnum primer makes your muzzle velocity ES higher, that's a sign you should avoid the magnum primer and go back to the standard type and get your velocity gain by raising the powder charge instead.

Watch out for the velocity of an old load to change. There is no exact relationship, load-to-load, but pressure can increase by more than the fourth power (square of the square) of the change in velocity if the powder charge is unchanged. So back loads down and work them back up. There is no free lunch in ballistics.

There is a good article on primers by a former CCI employee, here.