Primers in 375H&H w/fast burning powders?????

[1Shirt]

Have been shooting a lot of 375H&H with the 350BB Lee bullet with unique and Blue Dot recently for offhand/plinking loads. Have always used mag primers with the big case regardless of the burning rate of the powder I have loaded, and had pretty good results/no fillers. However I wonder if it is necessary to have mag primers with fast burning shotgun powders. Would be interested in the comments of others who have actual experiance[smilie=l:. By the way, I weigh all finished loads on a digital scale for consistency, and double charges of fast burners are to be feared!
1Shirt!

[Tatume]

No, magnum primers are not needed in the 375 H&H with appropriate rifle powders, and especially with pistol/shotgun powders. My favorite powders for the 375 H&H are 4895 (IMR and H), IMR 4064, and H4350. Charges of H4895 can be reduced to 60% of book maximums ( http://www.imrpowder.com/PDF/Youth%20Loads.pdf ), thus making it an ideal cast bullet powder.

The only times I would recommend magnum primers in the 375 H&H are when slow burning rifle powders are used in extremely cold conditions (well below zero Fahrenheit). However, slow burning rifle powders are not appropriate to this cartridge anyway.

Take care, Tom

[rockrat]

Can't help you there, but if you ever use 4759, I find mag primers help alot.

[Outpost75]

In the .375 H&H using reduced loads with #375449 cast of wheelweights, loaded as-cast and unsized, tumbled in Lee Liquid Alox, using 12-13 grains of Bullseye, my friends and I for many years have used Federal 210 or Winchester WLR primers with good results. These two standard primers give ballistic uniformity comparable to CCI 250 or Remington 9-1/2M primers.

I was told by a Winchester Engineer that their "magnum" primers contain the same mix, are made on the same manufacturing lines, but are separated by sorting lots to isolate those primers having pellet weight at the maximum range of allowed tolerance, so the primers are nominally the same. Their primer mix is also similar to that in the government primers in that an aluminum metallic fuel is added, which is intended to improve ignition with spheroidal powders by throwing hot incandescent particles through the charge. He says the desired product of an efficient primer is HEAT - NOT explosive force!

The Federal 210 primer is largely identical in its action, and differs only that their proprietary primer mix uses "normal" lead styphnate instead of "basic" which is used in the government mix. The difference is not important except in the way it influences formation of the crystalline structure of the priming compound as it dries, and the suitability of the priming mix for different charging and assembly methods, depending upon the manufacturing process used to charge and assemble the primers in production.

So the bottom line is that is using standard large rifle Winchester or Federal primers, in the .375 H&H and similar large cases, with fast-burning pistol or shotshell powders, so-called "magnum" primers are not necessary. If using other brands of primers, "magnum" primers may be beneficial to aid ballistic uniformity when small charges are used at low loading density in these large cases.

This statement is based upon more than 30 years of experience among experienced professional hunters and members of the Safari Club International who have used tens of thousands of cast loads for shooting camp meat for biltong, as well as for practice and recreational shooting.

The #375449 bullet when cast from wheelweights weighs about 265 grains, without gascheck. A charge of 11 grains of Bullseye is the minimum recommended to always exit the rifle barrel and gives 1000 fps. Better is a charge of 12 grains which gives 1120-1200 fps depending upon barrel length. The most which is recommended for plainbased bullets, or GC bullets used without their GC is 13 grs. of Bullseye for about 1240-1300 fps, depending upon barrel length. This approximates .38-55 Winchester ballistics and is suitable for impala and similar sized game within 100 metres. It also works well on whitetail deer at woods ranges.

When typical bolt rifles are zeroed at 250 yards with the 235-grain Speer HotCor spitzer bullet at 2800 fps, or at 200 yards with the 285-grain Grand Slam at 2650 fps, these cast loads shoot close to point of aim at 50 yards or metres. Out to about 100 yards or meters, using a duplex reticle, the bottom post is used to approximate correct holdover, which needs to be confirmed with the individual rifle, but is usually "close enough" for use without rezeroing if you have practiced with the load and can nuance the hold.

[btroj]

I am currently using Rem 9 1/2 with my 2400 loads.

[1Shirt]

Good comments! Thanks!
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