I am about to load up .375's for the first time. One book I have referred to mentions Winchester Large rifle Magnum primers. Are they really needed, or will a standard 9 1/2 or large rifle primer do (I have Rem, Winchester LR and CCI to choose from) ?
thanks ahead of time
Rick

Conventional wisdom seems to indicate using mag primers in loads with charges over about 50 grains, and for some ball powders. I have used both standard and mag and have not had any issues. I suppose in very cold temps a standard igniter may not reliably light off a heavy charge of slow ball, but....

Magnum primers are recommended and be sure to work up your loads carefully. If you have a safe load with standard primers be sure to rework your loads if you switch to magnum primers. They can cause a max safe load to become unsafe in some cases.
Good luck.

I use Federal 215G on all Big bores. 375H&H, 375 H&H Flanged Magnum, 500NE, and 416 Rigby

Use Magnum primers.

Thanks for the good advice. I'll get myself some magnum primers. What a great resource this is!
Rick

good luck on finding magnum primers.

I hate to disagree but i use winchester large rifle primers with my 375. I duplicated the load from the man that gave me the rifle.

The outfitter with whom I first hunted in South Africa suggested I try RL 15 (I believe it was 74 grains) over large rifle primers (CCI) and 270 gr Barnes TSX. This has worked spectacularly well and I haven't changed a thing since.

He felt that the LR primer was possibly less of a pressure problem in the heat. I can't speak to that question; however, that load and combination is accurate and effective of game up to zebra and gemsbok - the largest I've taken with it.

quote:

Originally posted by Oday450:
The outfitter with whom I first hunted in South Africa suggested I try RL 15 (I believe it was 74 grains) over large rifle primers (CCI) and 270 gr Barnes TSX. This has worked spectacularly well and I haven't changed a thing since.

He felt that the LR primer was possibly less of a pressure problem in the heat. I can't speak to that question; however, that load and combination is accurate and effective of game up to zebra and gemsbok - the largest I've taken with it.

If you have a warmish or hot load in a case using LR primers and then switch up, it will give a pressure problem as we use a rough guide of "a Magnum primer is equivalent to 2 - 3 grains of powder".

Another Fed 215 user for magnum cases.

I've used Fed 215 primers in my 375 H&H for years and with great results. I experimented with 210s and had great results as well. I've come to the conclusion that if your powder oad is less than 80grs of powder, standard primers work well. jorge

I have had good luck with Remington large rifle magnum primers in my .375's. Several loading manuals use them in the .375 as well. They are generally the least expensive as another bonus.

Good luck.

Right now In am using CCI LR mag primers in my .375 with the Sierra 250 gr Game King. I am getting groups in the 1.25" - 1.5" range (measured outside to outside not center to center).

I've used Federal, CCI mainly, and Winchester. Use magnum primers. I load 76.5 grains of IMR 4350 and that charge needs a magnum primer. I have no idea why anyone would reccommend less. I get nine/ten loads per case with no problems.

Thanks for all the good info. I checked with my local shop; the only large rifle magnum primers they have are CCI's. Is it ok to substitute for the Rems or Wins as long as I am no where near max loads?
thanks again
Rick

Yes. I use mainly CCI's because that is what was available.

Some say the Fed 215's are better. I have only chronoed my load mentioned above with CCI's. That's max Hornady book load for the 300 gr. round nose Interlock. Some guys go to 77 grains of IMR 4350. I load the A Frame with the same 76.5 gr.charge. That's .2 gr. over book. Makes no difference.

I get 2550 average on a five shot string out of a 24" Mod 70 Safari Express. I forget the SD, but it ain't bad. The only thing I don't like about CCI's is they are maybe a thousandth bigger than the Federals and Winchesters, and won't feed well through my progressive Dillon press.

BTW, Dillon told me not to load Federal primers into the feed on a 650. They have had cases of sympathetic detonation with the Federals.