I am new to reloading the 375 H&H, but having tried some slower powders that should produce a high velocity I am not happy with the amount of force it takes to seat the bullet. Using IMR-4350, and the 300 grain Sierra BT, I really have to squeeze after a long drop and some tapping.

IMR-4895 seems to work up to max loads without needing compression, so I like that better, but a slower powder should be the best choice.

WW760/H414 seems to be the powder of choice on the forum for this round. If you have used it, does it need compression without seating the bullet out? How clean does the powder burn in the 375?

Are their other single base powders that do not need compression, that have a burn rate similar to IMR-4350?

Looking at the bulk densities of powders and their burn rates, 760/H414 do look the best, but I am looking for advice.

Thanks,
Arniet

The Sierra manual favors IMR 4064 for the loads with most of its bullets. There is no compression with that powder, and it is a good one in the .375 H&H. A dandy in fact.

You might look at RL 15.

A often overlooked, yet awesome powder for the 375 H&H is Win-760. I have used this powder with great results, excelent accuracy and velocity

The 300gr. Sierra BT is a long bullet for the .375H&H.


You can check the loads here , check the Sierra manual, or call Sierra's ballisticians for leads on a load with that bullet.

George

My 375 HH loves Reloader 15

IMR4350 uses about 4 grains less powder than H4350 for maximum loads.

That works great for me with the 260 grain Partition.

My 375 loves IMR4064 with the 300 grain TSX

I don't approve of being a one bullet one powder freak, but I see no reason to load anything other than Barnes bullets and R-15 in my 375 H&H.

Arinet,

I'm not a one bullet, one powder kinda Guy either.....

The Federal & PMP cases I'm using will not hold anywhere near the amount of IMR or H-4350 that some folks claim can be crunched into a 375H&H case.



Perhaps another manufacturer's brass will hold a few grains more powder without having to use alternative methods to get it settled into the case. The powder alternatives noted above are certainly an option but I don't use them for other cartridges and for the sake of powder consolidation efforts tend to powders that are suitable for other cartridges I load for; IMR & H-4350 being a good example.

The Sierra 300 gr. SPBT's are a long-g-g bullet for the 375 H&H. The Sierra 250 gr. SPBT's are an option as they take up much less space and are certainly adequate any North American game other than big Bears. It did take a bit of tweaking to get the 250 load right though.

I prefer the Hornady 300 gr. RN's, the cannelure is situated low enough on the bullet to not take up too much powder space, affords enough room to get a resonable quantity of IMR or H-4350 into the case without having to crunch too much and and the RN form w/cannelure makes for suitable OAL without magazine length difficulties. I also crimp the finished rounds with a Lee Factory Crimp Die.

Even with the MTM long drop tube (O.K., they're not that long....) it takes a coupla seconds of holding the case next to the Tumbler to get the powder settled below the shoulder/neck junction of the case too.

Good Luck!

I have had great luck with IMR-4064 IN the .375 H&H...Rl-15 is also a good powder, it fills the case but I have never experienced compaction in the .375 with 4350..mild compaction is desirable, its when you really pack that powder you get into trouble. There are certainly better bullet choices out there than the 300 gr. Sierra, such as the 250 Gr. Sierra, a bullet that really performs on deer and elk. but for hunting I really like premium bullets.

I'm w/ Ray. I tried the "Traditional" pwoders like 4350, but when I tried RL15, that was what gave me best accuracy/vel. w/ good load density.

I tried 4064, 4350 ,etc, but with Win-760 I look no farther. Easy to meter fills the case just right great accuracy and VERY good velocity.

With all the load development I've tried Reloader 15 is producing excellent results for me.

I have had good results with 70gr of Varget under a 270 Hornady SP.

I normaly load a 270 TSX over 74gr of VV N550. I amgoing to try running a bit higher charge of N550 to bring the speeds up a bit into the same range the hornadys are shooting well in.

Rhys,

I tend to the heavier 300 grainers but I've also had really good accuracy & velocity with both VVN160 & VVN560 in the .375H&H, too.

quote:

Originally posted by Rhys:
I have had good results with 70gr of Varget under a 270 Hornady SP.

I normaly load a 270 TSX over 74gr of VV N550. I amgoing to try running a bit higher charge of N550 to bring the speeds up a bit into the same range the hornadys are shooting well in.

Gerry,
I'm cooking up a test load with a Barnes 270 TSX and Varget myself. What kind of speed are you getting w/ your 70gr load?

Gerry & Rhys I'm supprised more guys don't use Varget. For me thats the GO TO powder for the .375 especialy with the longer .270&.300 Gr. Barnes TSX. I don't have any Chrono info for the .270 But the .300Gr does an honest 2500 f.p.s. with 69 Gr of Varget. Definatly a hot load, but my Montana 1999 with a 24" Douglas handles it in stride. I was never able to get 2500 F.P.S. with any of the other recomended powders no matter how hard I banged and pounded on them to stuff it all in. My shooting buddy has been getting some great groups useing Varget in his .416 Rem Mag. Almost all of the testing with Varget has been done in 90+ degree weather here in Fla. Cheers George

Win-760 will solve your speed issues with the TSX bullets

My load of 70gr of varget with the 270gr Hornady SP gives me 2790, and the 74gr of N550 with the TSX was at 2680. The N550 load is way on the mild side. I know the speeds look highbut also keep in mind my .375 also has a 30" Lilja, it consistently runs about 200 fps faster than the manuals say I should be.

Rhys,

30" .375H&H tube - man, you're almost half way closer to anythng you shoot than me! Mine's been whacked back to 20".

Pretty immpresive speeds with those 270 grainers bye-the-bye.

George,

I'd try many more powders (if the cost & availabilty of many of them was less tha hit or miss here in Europe, too) and am also legally restricted to the amount of powder I can have in my residence at one time. I certainly persuse the loads offered here and various powders but when push comes to shove have to go with what I can obtain for consistancy nad common usage among all the cartridges I load for, too.

You may want to try Ramshot Big Game. After using IMR4350 and Win760 for years, I decided to try something new. I found the most accurate load ever for my 375: 75 grains of Big Game under the 300 grain Barnes TSX, F215 primer, Hornady cases. Chronographs 2,550 fps from my 24" barrel, which has a 1:14 twist. Many sub 1" 3-shot groups, several less than 1/2-inch.

quote:

Originally posted by Rhys:
My load of 70gr of varget with the 270gr Hornady SP gives me 2790, and the 74gr of N550 with the TSX was at 2680. The N550 load is way on the mild side. I know the speeds look highbut also keep in mind my .375 also has a 30" Lilja, it consistently runs about 200 fps faster than the manuals say I should be.

Rhys,
You should be getting higher velocity with that 30†barrel. I am surprised it is only 200 fps. More. I would watch for pressure sine’s though on your “70gr of varget with the 270gr Hornady SP gives me 2790,†load that is above the max load in my Hodgdon manual. The book shows 67 gr for 2620 but you are already at 51,600CUP with this load in a 24†barrel. Just be carfull.
I have just started to load Varget. The first load with 225 gr Hornady bullets averaged 2379 with the starting load of 65gr The SD was 43.6 and my Kimber didn’t like it. I was getting about 4-5 in groups. I tried the starting load of 58 gr with the 300gr SIE SPBT. This went into about a 1-1.5 in group. But is only getting 2036 average with a SD of 17.5. I plan on trying a load closer to max listed of 62 gr and we shall see how that shoots.
On the subject of the 4350 powders. The IMR powder is a little bit faster than H4350. I think you will have a full case starting around 78 gr but I got good accuracy with 81 gr IMR 4350 and a 300 gr Hornady R.N.. At about 2590. The secret to getting all the powder in the case, I hold the case and powder funnel against the vibrating case tumbler settles things nicely.
Bill

I misspoke on the amount above listed that my velocities are. Hornady lists their 270gr SP at 2600 with 71.6 of Varget and 2700 with 75.1 as a max load. I was getting 2790 with 70gr of Varget. So I'm getting 300 - 350fps over the listed velocities. Hornady lists Varget between 61.1gr and 75.1gr.

I'm not even starting to get pressure signs at those loads. They are mild enogh in that rifle that I didn't get any pressuresigns after leaving them in the car in direct sun on a 98 degree day for 4-6 hours before firing a few to see if the temp would cause a problem. They shot well in the rifle so I left well enough alone.

Arniet, your best high-load-density, "slow" burning powders for the 375 H&H and 300 gr. bullets are W760 and Vv550, and both are quite similar in performance. With ~78 grs of either and a 24" barrel you should be able to get ~2700 fps. I would chronograph your loads as you work up to this velocity. I would stop after you get 2700 fps - that is with a 24" barrel. That's ~4900 ft# of energy - good load.

Hi Ackley, any suggestions for my 350g Woodleigh bullets with respect to powder?

Thanks,
Chuck

Chuck375, I'd suggest the same powders, although you might also consider Vv560, which is also very high load density like Vv550. Vv560 may work, given the heavier 350 gr. bullet. Also, I would not be afraid to compress the powder. It's never caused problems for me, except at a certain point the bullet may push back out (but you can crimp) and you can cause expansion of the case causing difficult chambering (although case extraction is usually not a problem). Finally, with the slow burning powders it's hard to run up pressure with the massively underbore 375 H&H.

W-760 always gave me best results. Plus I use it in other calibers and I like to keep things simple. It is my main powder for 7x57's, which are my most used rifles.

WOW-just counted my selection of powders situated above this computer. There are 21 different powders there!

Anyway, I got my .375 back in the '80s and for years used 82.0gr of 760 behind a 300gr Nosler Partition. This load came from a magazine article back then-probably The American RIfleman. Later learned that was an overload and have sinced reduced the powder charge to 78.0gr.

I did notice that the recoil was not quite as snappy!

78.0gr of WW760 behind a 300gr Woodleigh SP give me 2576 fps from my Whitworth.

FWIW-I never could get enough IMR 4350 in my cases. I don't mind a compressed load, but this was never even compressable for me.

RL 15 gets me great results.

quote:

Originally posted by boatammo:
RL 15 gets me great results.

Yup

I get 2550 out of 76.3 IMR 4350 w/ Hornady 300 grn Interlocks and Interbonds, consistently, with MOA out of my 24" Model 70. No reason to change. That's the max book load for that bullet.

Ray's load of 67 grains of RE 15 with the Woodleigh 350 PRP gives me an average of 2373. That's with Fed 215 primers. CCI primers drop it by about 50 fps, with MOA or slightly more. Minute of buffalo, and all that.

Chuck375, I'd suggest that ~81 grs of Vv560 with your WL 350 will produce ~2550 fps and ~5050 ft# of energy with a 24" barrel. Again, work up to it, while looking for pressure signs, but I think it should work. Compression will be necessary. Great load!!

I have had excellent Luck with 76.0grns of IMR-4350 and the Hornady 300grn bullets in my RSM 375 H&H (well that was before I got silly and bored out the barrel to .50 Cal). Not the fastest but they sure grouped well.

Brad

Normally I am not a fan of ball powders such as 760 or H-414 particularly in big cases, the 7x57 being my sole exception and its a much smaller case. I usually opt for a stick powder if I can.

In the case of the 375 H&H I have always leaned to IMR-4064, and lately RL-15 suits me as well.

I do love the way ball powder meaters out but I don't like it for extreme hot and cold climes, and I have seen it fail after long shelf life. I have also read a lot of bad reports on it, true or false I have no clue.

I'm not saying its not a good choice, just that I am a little suspecious of it, and have good luck with other powders, so I have not opted to use it much. I am interested in field results with ball powders and would like to play with it a little more.

Win-760 and H-414 are the same powder, FWIW

Thanks Ackley, I will work up to it slowly and try Vv560. Never used it before. I'm going to start with H4350 and see what I get with it first. What do you suggest as a starting load with N560 and the 350g Woodleighs 75g?


Chuck

I've said it before, but if a .375 won't shoot with RL15 or 4064, it won't shoot well with anything. RL15 is the go-to powder for a number of calibers.