Probably not the place to ask this but I thought I might get more responses in this forum so here goes.
After reading as much as I can read here and other forums and sites it appears the the two most common powders for pushing a 300gr.bullet out of a 375H&H seem to be RL15 and IMR4064.Seems to be as many liking one as the other.
What are the differences between these powders in terms of accuracy,velocity ect. or is that rifle dependent? I'm getting ready to start working up loads for my 375H&H and would like to ask which one should I start out with first?
And what are any loads that will get me 2500+fps that work for you?
Thanks

A load my Ruger RSM likes (23" bbl) is...

67.0gr IMR-4064
CCI200
W-W cases
Hornady 300gr RN

I'm getting just over 2500fps with this load and it's accurate/pleasant to shoot and happens to be dead-on with my express leaves also.

rw2,

You won't find it in any current manuals but 80gr. IMR 4350 will work great but you'll need a drop tube to get the load in the case. It is compressed but it keeps the bullet from being driven back in the case during recoil while in the magazine. This powder and a Fed 215 primer in W-W cases has worked exceedingly well for me in several 375's. I get 2540 fps from my current 375 with a 23" barrel and this load. Accuracy is very good with the 300 gr. SAF also. If you do some research you'll actually find some old Bob Hagel loads that list 84 gr. of the same powder with a 300 gr. bullet for over 2600 fps.

Good luck,

Mark

THe 375 is pretty forgiving. IMR 4895, IMR 4064 AND R-15 all work well with the 300 gr. bullet.

.375 H&H Magnum
300 grain bullet seated to 3.6" COAL
Winchester brass, 2.84" trim
Federal 215M primer
70 grains H4350 START
81.5 grains compressed H4350 MAXIMUM
2645 fps from a 24" barrel
Work up carefully from START toward MAXIMUM watching for signs of excessive pressure or velocity

I used the RL15 powder since my reloading manual claimed it was the most accurate tested. I get good tight groups for a big bore gun. I would try both and see which gives the best results. Also, the bullet used will also be a factor. I generally use Barnes-X or Noslers.

Good luck

If you find some French powders at a garage sale, 71 grains of Tubal 5000 is great with a 300 grain. Fills the case right up to just under the bullet with most profiles and gives great consistency in velocity and accuracy.

Ok Thanks! I have access to RL15 and IMR4064 so I'll start there.Nobody has any 4350 in stock around here right now and won't order me any unless I pay the hazards fee and get a case.So I'll start there and if no good results I'll find some 4350 if I have to drive 50 miles to do it.

Put me down as a big fan of RL15!

I know that many people here recommend IMR 4064 and RL 15 for it, but I think that the best powder for the .375 H&H is Hodgdon 4350. I doubt that you can get enough of the stuff in a .375 case to give you too high pressures, but go with Hodgdon's max loads.

83 gr. of H4350 in a Winchester case with a WLR primer (NOT a magnum primer) gave me 2870+ f.p.s. from a 270 gr. Speer boattail bullet.

With IMR 4064 -- 72 gr. -- the best velocity I could get with that 270 gr. bullet was 2695 f.p.s. but it was a very accurate load.

With a 300 gr. Sierra BT bullet, 81.5 gr of H4350, same case and primer as above, gave me 2770 f.p.s.

All these loads with H4350 are highly compressed, but so what? They are also very accurate.

Check this load: 76gr H-414 with any 300gr bullet, Fed 215 primers and WW brass jorge

RL15 has been the powder that has given me both the highest velocity in my 375 but the problem I've had with it has been the inconsistently between various lots of powder. The most extreme example was one lot gave me 2600fps with no signs of excessive pressure (lots of recoil) with the 300gr Nosler Partition but the next lot showed serious pressure signs at 2450fps at a charge several grains less than the previous load that produced 2600fps.

I finally gave up on RL15 and switched to Varget for my 375....the best load here produced 2550fps and accuracy, while still sub-moa for 3 shots, wasn't as good as the faster load with RL15.

Great Info! Thanks All

Jorge thats some impressive group!

I just used the three 4350s (IMR, H, and AA) and mine liked the latter the best. Very uniform, easy pressures.

Russ

I use my all american load of IMR 4350 in WINCHESTER brass, winny primer (non-mag) 76 grains of this along with the Woodleigh's in 270 grain or in 300 grain and so far has worked vary well in well over a dozen different .375 HH's it's been shot in. Everthing I've shot pretty well died fast enough. None ever made a new track after being struck. They all have died in there tracks. I know not everyone will agree, but thats how I like it. I know many like a bullet to shoot clean through an anmial to leave a good blood trail. But for me (and only me) I want them dead when struck. I call this my all american load because I only hunt the americas and don't know if this would work outside the americas.

quote:

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Originally posted by LE270:

...With a 300 gr. Sierra BT bullet, 81.5 gr of H4350, same case and primer as above, gave me 2770 f.p.s.

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You're the one who read the numbers off the chronograph. Are you sure that's not a typo? 2770 sounds too damned fast for the H&H.

I use IMR 4350 right now, because I've got a big 8 lb. keg I bought for something else. I hope to compare the other 4350's. I get 2550 fps with Hornady 300 gr RN or FMJ bullets without exceeding the published max loads. With a drop tube, I get to 2500 fps with the bullet just sitting on the powder. Negligible compression, little or no rattling.

H. C.

quote:

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Originally posted by HenryC470:You're the one who read the numbers off the chronograph. Are you sure that's not a typo? 2770 sounds too damned fast for the H&H.

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Yes. I read the numbers off the chronograph myself, and that's what it said.

My .375 H&H is a Remington 700 Classic with a 24" barrel.

Someone else above recommended Varget. The people from Hodgdon recommended it to me too for the .375. I tried it and got low velocities from it, lower than what I got with IMR 4064.

In fact, although I know some people like it a lot, I've never found a good use for Varget. It does give me excellent accuracy with 150 grain bullets in my 30/06, but at the sacrifice of about 200 f.p.s. from what I can get with H 414.

The best accuracy I have gotten with 300gr Swifts has been with Varget.

Norma Brass
61.5gr Varget
WLRM primers
300gr Swift A-Frame

2430fps, es 17.4fps, sd 22.6fps

Varget is also very resistant to temp fluctuations, less than 1" poi shift at 100 yds between 88*f and 50*f.

I have tried most of the powders mentioned above, but my best results have been with H4895. 67gr with a 300, and 69gr with a 270. In my M70, both loads are very accurate, and seem to kill what ever I shoot with them.

DGK