I was wondering if Magnum Primers produce more velocity than Standard primers,and if so, how much?
Thanks,
Jeff

I had the same question just a few months back. I loaded up some 338 Win Mag loads with 215M (magnum) primers, and the same identical load with 210M primers. The propellant was RL22. To my surprise the 210M primer loads fired under the same conditions, were 5 fps FASTER than the magnum loads. While three rounds of each doesn't necessarily tell the story, it did tell me that velocity really isn't affected, at least with this load in this gun.

I usually change primers only towards the tail end of load development in most every gun. I've never seen more than �30 fps difference in any of the primers, and even then I couldn't be sure with such a slight difference that it wasn't some other factor, such as slighly different case capacity, different ambient conditions, fouling in barrel, etc.

It's interesting to see Bob's result.

I did a test in a 30-06 class cartridge with H4831 and with H4350. There was no difference in pressure or muzzle velocity with CCI normal vs. magnum primers.

I was surprised, to say the least.

So now you have two different experimenters coming up with the same answer...

I've seen test series where the magnum primers produced slightly LOWER velocities and pressures. I don't think there's any way to accurately predict which way it goes, but IMO it won't make a really big difference in most of the usual rifle cartridges and loads. It's safest to work it up again when you change any component.

Conversely, I've also seen reports of too-high pressures caused by "weak" primers, which may relate to some of the ongoing discussions about hangfires and kabooms.



I've seen a trend toward better velocity consistency in several rifle loads with the magnum primers. I think that when I use up my current stock of CCI 200s I may just standardize on the 250s for everything as I have some magnum loads that really need them and it'd simplify my component inventory to use them across the board.



BTW, I don't think that our magnum Boxer primers are any hotter than, maybe not as hot as, some of the Berdan primers that the Europeans have used in standard cartridges for many decades. With no anvil in the cup, those primers hold more mixture, and some are also of larger diameter than our Large Rifle primers.

Well so much for that idea. Some of my loads in my .270 Win could use a little more velocity and consistency. Looks like I'll have to settle for the consistency.
Thank You Gentlemen,
Jeff

I did a side by side test of the 215 vrs CCi's Br2 in a 7mm WSM using RL 22 and a 140 SPT. The velocity from the magnum primers was 25 fps higher. Accuracy was good with both loads.

This is not conclusive nor a laboratory level experiment. Since the cartridge is large anyway I went with the magnum primers.

Jeff, some twenty years ago, I tried Federal 215 primers instead of Federal 210s for my .270 Winchester loads. To my surprise, I gained over 100 fps. simply by changing primers and with superb accuracy to boot. Then I read a .270 piece by Jack O'Connor in an old edition of "Handloaders Digest", and noticed that he used CCI 250 magnum primers in his .270 Win. loads. Later, I read a Dave Petzel piece in which he stated that he preferred magnum primers for his .270 Win. loads as well.

Next, I tried Federal 215s with my old, standard .30-06 load with Winchester cases, IMR 4831 powder, and 180 gr. Nosler Partitions. I gained over 50 fps., velocities became more uniform, and accuracy improved slightly.

According to Alliant, standard primers are advised with the Reloader powders. Now for some ten years, I'd (I guess ignorantly) loaded Reloader 22 in the .300 Win. Mag. with Federal 215 primers and 180 gr. bullets, but with superb results. Finally, I decided to try standard primers, in this case Federal 210Ms. Velocity took a dive by over 100 fps., extreme spread went from 12 fps. or less to over 150 fps., and accuracy went to heck in a handbasket. I went back to 215s and all was well, so, at least in this case, "official position" be dipped!

The truth is, there are no hard and fast rules when it comes to powder/primer combos, or much of anything else. You must experiment, and you must use a chronograph or else you're literally "shooting" in the dark. Every rifle and every lot of powder is a law unto itself.........

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