Mag primers vs. Standard in the .45-60

[KirkD]

A few weeks ago I was loading up some .45-60 cartridges for my old Winchester '76 when I finished one box of primers and then started a new one. It wasn't too long into the reloading session when I realized that the old box was for standard large rifle primers and the new one was for magnum rifle primers. I got to wondering what difference it would make, so a few days ago, I tried two different loads, each with the two different primers. The bullet was the same for all tests, a 326 grain cast bullet with a GC (actual weight lubed, sized, and GC'd). For each test, 5 shots were fired over a chronograph.

Load #1: 26.2 grains of 5744
Winchester large rifle, Standard primer: 1,337 fps E.S. = 9 fps S.D. = 4 fps
Winchester large rifle, Magnum primer: 1,362 fps E.S. = 48 fps S.D. = 17 fps

Load #2: 25.5 grains of IMR 4227
Winchester large rifle, Standard primer: 1,286 fps E.S. = 65 fps S.D. = 23 fps
Winchester large rifle, Magnum primer: 1,313 fps E.S. = 67 fps S.D. = 26 fps

For Load #1, the Mag primer gave an extra 25 fps and poorer burning consistency, judging from the increased E.S. and S.D.

For Load #2, the Mag primer gave an extra 27 fps and about the same burning consistency.

Normally, an extra 25 or 27 fps is not a big issue, but since my bullet is already 9 % over weight, and I shoot an original '76, I don't like to be over the original black powder velocity, which varies according to sources used. My copy of the 1896 Winchester catalogue puts the original velocity at 1,271 fps for a 300 grain cast bullet, and a later chart puts the velocity at 1,315 fps for a 300 grain cast bullet. My own black powder chrony results for 60 grains of FFg gave 1,307 fps with an E.S. of 78 fps and an S.D. of 29 fps using original balloon head cases. With this particular 326 grain cast GC bullet, my preferred velocity is right around 1,300 fps.

[Ben_Rumson]

Thanks for the report. Good info to know.

[Chuck 100 yd]

Good info. !

[Kansas Ed]

Kirk,
Once again, great post. I've never used Mag primers for anything, and as such know little about them. What is different characteristically? Are they supposed to give a hotter flame, longer duration ignition, or would one suppose that the only real difference is the cup thickness? I've often used CCI-BR primers in my rifles, and wondered what the difference if any was supposed to be. I would have thought strictly from the "mag" designation that they were giving a hotter ignition, which I would have thought would give more consistent ignition, thereby decreasing ES and SD. Apparently that isn't so. I'm also a little shocked that the vel avg is as close as it is...fully expecting at least a 50 fps difference in loads, and more likely a 100 fps difference. Do you have any insights as to why there was as little difference as there was?

Ed

[KirkD]

Ed, I'm afraid that my actual knowledge of mag vs Standard primers is pretty much limited to this post. From my results, it seems that all I can say about Mag primers is that they add a bit more energy to the burning, increasing the pressure slightly, hence the muzzle velocity. There seems to be no advantage to using them in a .45-60. If anything, they give worse performance (E.S.) with 5744.

Perhaps mag primers are designed for larger powder amounts, like what one would find in the 458 Mag, or the 460 Rem.

Since I have a box of 1,000 Mag primers, I'll have plenty of opportunity to try them out in other calibers. However, from what I'm seeing here, when this box is used up, I'll be sticking with the standard Winchester primers.

[Kansas Ed]

I normally use the CCI-Br or Fed-Match for everything, but with the primer shortage, I bought a brick of the Winchester Lg Rifle's to try. I started using them in the 40-72. Have you seen much difference in brands? I may load the last loads I tried in the 40-72, using a different brand , just out of curiosity to see if they show any difference.

So many combinations and variables to try, and so little time to shoot

Ed

[Ben_Rumson]

I've read that at least one company selects magnum primers by lot from standard primers...A primer lot testing hotter than normal gets moved into the magnum category. Read that over on the Cast Bullet Forum.

[KirkD]

I do have a box of 1,000 Remington large rifle primers I should try.

[Old Savage]

Kirk,

A while back I saw a test of primers in print. The Win Large Rifle was about the most consistent though obviously not the hottest. I have used them in over 90% of my rifle reloading. By the way - how are the boys progressing?

[Modoc ED]

Here's a link to some pictures of primers being fired.

http://www.6mmbr.com/PrimerPix.html

Here's an interesting article on primers and pressure.

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

[Bartman]

Hi guys, nice post I have had a little experience with mag primers. I started out loading normal large rifle in my 45-120 sharps replica and was getting really inconsistent ignitions and sometimes even unburnt powder lumps still in the case (smokeless powders with fillers at 45-70 pressures in modern replica) I heard about the need for magnum primers in large capacity cases and started using them and have not had an issue since. As far as I can tell the difference is not weather they are hotter but the size and time curve of the flame is bigger to reach further into big cases with big charges of powder as they were originally designed for large magnum cases. Just my two bobs worth. Cheers
Bartman, mad levergunner from down under.

[Ysabel Kid]

Kirk -

Thank you for sharing. Interesting info for sure!!!

[piller]

Thanks for the information. I don't use the Magnum primers, and since I have no experience with them, information such as yours is a big help.

[TX Gun Runner]

My 32-40/200gr and 40-60/400gr Maynard I use large pistol with my 4227 loads which I get no leading and groups are super tight . I keep my speed around 1450 FPS for both of them . If I use the rifle primers I get a little leading with a plain base bullet with a 25 to 1 mix .

[Sixgun]

Guys,
There's a good write up on primers in the new issue of "Shooting Times". Pretty much of what they said has confrimed my testing over the years.

For the most part, magnum primers are used in large capacity cases that use slow burning powders such as the heavy magnum rifle cartridges or some of the newer hot shot handgun rounds. Some brands of magnum primers are made to give a hotter flash, while others are made to give a longer duration. I only use them for that purpose, (357 Max.) or most all ammo I am using while elk hunting in very cold weather. I hear and read where other guys use them for black powder.

The times when magnum primers can be dangerous is when substituting them for a regular primer in a load that is at or near maximum pressures. Or, according to Shooting Times, in small cases as the initial spark can push the bullet out of the case before the powder ignites, resulting in two pressure spikes. ( I think I read it like that--better check )

I tested them with AA 5744 and got the same results as Kirk--larger ES and slightly more velocity.Accurate Arm's techs. told me I'm wasting my time playing with magnum primers when using 5744.

Remember, Elmer Keith, Jack O'Conner, and all of the last "greats" were doing their hunting in all kinds of weather and all kinds of powder, as slow as 4831 and thats all they had were standard primers.