375 ultra mag

[jeep4]

I have enjoyed reading your Forum. I was wondering if you could suggest a cast bullet load for this cartridge.It kicks a bit with full power jacked loads. I have a real old lyman reloading manual that suggests 20-28 grains of unique for the 460 weatherby whiuch seems to hold as much or more powder than the 375 ultra mag.

[Veral]

  I haven't loaded for either the 460 or 375 Ultra Maz, but have played with a 458 Win mag quite a bit, in a Ruger #1, and learned that it could come back pretty hard when I 'powdered the fanny' of the bullets a bit too heavy!  Unique is way too fast a powder in my opinion for large cartridges.  Better choose a ball rifle powder that fills the case at least halfway, so you can't get a double charge by accident. (They are NASTY noisy with a big cases!)  The slower powder will get things started a lot softer, which means a less sharp recoil rap, which is easier on the lead bullet also. 

  If you choose to use Unique, it will sure use a lot less powder than a slower ball powder.  Just be sure to charge all cases in a loading block, then check each with a stick to be sure powder level is the same in each before loading the bullets.  That's the only sure way I know of to prevent a double charge from happening someday.  In case I'm not getting this double charge issue through solidly, it is better to sit on 10 sticks of dynimite and set her off, so you know you wont's suffer.  If you double charge that 375 there is some chance you won't die!  I blowed a 30-06 up about 45 years ago, and it seems I can still hear the report bouncing around out there!  It was a double charge of 2400 behind a military ball bullet, made by someone else.  I had just the forend in one hand and the butt stock in the other when the dust and shrapnell settled.

[Nobade]

This is another good use of the duplex loads y'all were talking about a while back. This weekend I was shooting my 375 Chatfield-Taylor with a load of 17 gr. 2400 and 60 gr. WC872. 2200 fps with a 300gr. cast bullet, sub MOA accuracy out at 385 meters. That 872 is too slow for pretty much anything, but it sure works when duplexed in big cases. Yours holds about 25 grains more powder than mine, but the effect would be similar. And no chance of double charging.

As to that double charge, if you can get to play with Quickload sometime it'll really open your eyes to what a double load of fast powder can do in big cases. Like go from 25000 psi to 250000 psi really quick. Heed Veral's advice!

Me, I like Red Dot for that kind of stuff. It's really fluffy and takes up a little more room than Unique, and seems to give better accuracy. I tried Trail Boss, but that stuff is spooky. I won't use it again in rifle cases. 

[Hank08]

No chance of double charging unless you doubled the 2400.  34 grs. of 2400 under the 60 grs. of 872 might get kinda exciting.  You might just start with some cast loads for the
.375 H&H, probably 3031 or 4895 will do as well as anything.  I use 44.0 grs. 3031 in my .375 H&H with 275 gr. bullet.  Chronos 1875 fps in my M70 with 24" barrel will probably be around 1800 in yours.  Just right for the best accuracy with a gascheck bullet.  Shoot a deer with it and you'll find it's just as dead as if you had used a jacketed bullet.
H08

[jeep4]

Thanks for the tips on reloading cast bullets for the 375 ultra mag. I am a little leary of loading duplex loads.I kinda of like the idea of using 3031 or 4895 with 375 hh data. If I use 3031 at 44grains is there any danger in a case as large as the 375 ultra mag? In my Lyman manual thats the max for a 269g cast check lead bullet for the 375hh.

[Veral]

  You'll find that most loads from the Lyman cast manual will fill your large case less than half full.  but worst problem I had with their data was that most of the heaviest loads could not be used in temperatures above about 60 deg F.

  3031 is a popular cast bullet powder, but I've found 4198 to light up more uniformely and like it's pressure characteristics better, though it is slightly faster.   H335 and 748 are my favorites for medium heavy cast loads in large cases.  The largest I've used being the 7 MM mag and 458 winchester.