Primer question

[Bandit01]

Okay, I've been loading for a short while now. The first couple of weeks were difficult but now it's smooth sailing. As a matter of practice, I've always used Magnum primers for all of my calibers (.40 caliber; .45 caliber; 10MM; 357 Mag.; .44Mag). Generally, I use 2400 for all of my calibers but sometimes (lately) I've been using AA#7 for the 10MM and H110 for the 357 and .44 Magnum.

Speaking to an older gent with over 40 years experience, he told me that I don't need to use Magnum primers for all of those calibers and that by using something that strong, it could affect my accuracy. Generally, he said that I only need to use Magnum Primers in the .44 and when using H110.

Assuming that this is true, what's the general rule for using either Magnum and non-Magnum primers?

Honestly, I didn't think that it was a big issue. And to be on the safe side, I figured that it's best to use Magnum primers.

 

[Sam Adams]

My general rule is to see what the reloading manual says. If it says to use a magnum primer with a particular load, I do; if not, I don't.

If you don't already have at least 2 manuals, make sure that you have them. 2 is a minimum, so that you can compare the minimum and maximum loads to see that both are close. This prevents you from blowing up your gun and hurting yourself if there was a printing error (i.e. if the loads are vastly different, call both companies and find out if their data is correct). Fortunately, I've never come across such an error, but when you're dealing with firearms, you can never be too safe. I like the Sierra manual, as they will tell you what load is the most accurate for particular bullet weights. I've also got a Hornady manual. Nosler's is also supposed to be excellent, and Speer's has a good rep.

Also make sure that you keep up to date with the manuals. They constantly test, and new powders, new formulations for old powders, and new bullets are coming along constantly. You want the latest info, just as you'd like your doctor or lawyer to have the latest info. in their profession.

 

[Mal H]

Last things first - "And to be on the safe side, I figured that it's best to use Magnum primers."

Wrong! To be on the safe side, it's best not to use magnum primers.

Listen to your wise friend. Use magnum primers in calibers requiring them and with powders requiring them. That info is obtainable from reloading manuals and the various powder manufacturers.

Substituting a magnum primer with AA#7, a moderately fast powder, and using the powder load recommended in a load manual in a small high pressure caliber such as a .40 S&W, is a recipe for injury or worse. Accuracy could be the least of your worries.

 

[stans]

Magnum primers are needed to ignite slow burning powders like W-296 and H-110, some people like magnum primers for 2400, some don't, that seems to be the gray cut off for magnum requirements. For powders like AA#7 and faster you don't want magnum primers. For large size primers, Winchester no longer gives you a choice, they have only one grade of large pistol primer and it seems hot enough for most jobs. In long, thin cases such as 357 magnum, you really do need a magnum primer for the slow burners.

 

[Kamicosmos]

It's pretty much been said, but I'll add that I accidently loaded some .40 rounds with mag primers, and noticed significant case bulge when fired in my beretta 96.

I only use Mag primers with H110 loads in .44 and .357. I have been doing some testing with using 'normal' primers. The .44 has been fine, but the .357 has some unburned power. I think that might be a crimp issue though.

Mag primers do create quite a bit more pressure along with obviously higher flame temps...

 

[ftierson]

Actually, I don't use an mag primers, except for an occassional use of the CCI #34 primer in some semi-auto rifle loads.

I use CCI300 or WLP for .44 Rem. Mag and CCI500 or WSP for .357 Mag., both of which I load with H110 to be shot only in Win. M94 Trapper carbines. These loads work well for me. If I was shooting them in 4-6 inch barreled handguns, I would probably use mag primers for them.

Generally, I agree with those recommending that you stick to what's recommended in the loading manuals. And, as has been mentioned, you must keep up to date with your loading manuals...