magnum rifle primers question

[JR Hartman]

Hey, so recently at a sale, I asked for large rifle primers and when I got home I put the bag (with lots of other stuff in it) into the ammo locker.

fast forward several days.

Go to use the large rifle primers and find that they are Magnum large rifle primers instead. I know I should have checked, but I trusted the people behind the counter as they are usually spot on and have good service.

Now, I can't take them back, so can I use them?

I have heard that you just have to use slightly less powder in the load?

I do load 8mm mauser so its a fairly "magnum" cartridge. No not an actual .300 win mag or 7 mag, but at least its biggish.

Can I just dial back the powder? and if so, how much?

thanks in advance.

 

[Dunk]

If it was me and the loads are not on the hot side ,I would just use them.

 

[silverfoxdj]

I have used both and really have not noticed much of a difference

 

[rral22]

If I had a load I had worked up that I knew was "hot" for my gun, I would not use them as a replacement, but as others have said, if (and be honest) the load you have worked up is not listed as max. anywhere, then I would just use them. If you have a chronograph, and know what you were getting with the original load, it would be very interesting to run the mag primers over the chronograph to see if you can tell anything.

 

[rl4930]

What kind of mag primers? Some are hotter than others. And what is your go to standard rifle primer?

 

[JR Hartman]

both CCI. one large rifle primers one magnum large rifle primers.

I have done much other research and it seems that much data has been gathered on this subject already.

Apparently its from 0-25 f/s increase with magnums over standard of the same brand.

Many guys say that you in fact gain accuracy with ball powders due to a more complete and even burn.

What say all of you?

 

[rl4930]

If both primers are CCI, the mags might be a little hotter, I can't say for sure. The mag primers likely have a harder cup. I have chronographed mag vs std rifle primers and I didn't see a velocity increase with federal 210m vs. 215m

That was with a crappy chrony tho. Once I get the labradar, I'll do another test.

 

[BigUglyMan]

For years I have used CCI 250s or Federal 215s for standards like the 25-06, 30-06 and 9.3x62 because I hunted in cold climates and wanted to ensure positive ignition. I was doing the load development in the summer so I have no concerns that the loads are unsafe. You could tip a really hot load over the edge by adding a magnum primer after the fact but in reality our modern rifles aren't hanging on by their fingernails at max pressure...there is a fair amount of safety room built in to modern actions.

 

[laurencen]

got a bunch of mag primers with reloading purchase, tried them and did not notice any difference on 30 06 and 303

 

[martinbns]

I used F215m primers for the 270 that gave me the best loads in two different rifles.

Just work up like it's a new load.

 

[Dogleg]

American rifleman had a good article years ago about component changing in the 30-06. On the primer segment it was found that velocities often didn't change much, but pressures did. Up to 10,000 psi in some cases. In other cases nothing. The thing was, the higher pressure didn't necessarily come with the higher velocity.

You can use the magnum primers, just work up the load again to be safe. You don't necessarily have to do a full work up; just load one of each and see what you get. Wouldn't surprise me if you end up backing off a grain, and wouldn't surprise me much if you can't tell the difference either.