Reduced .375 H&H loads

[RickinTN]

I'm going to revive this old thread because I have my first 375 H&H on the way. I'll have to start with jacketed bullets and reduced loads. I'll probably use the Hornady 270 grain bullet because that is what I can find at the moment. Switching over to the 235 Speer sounds like a good idea when they are available. I have an offer to borrow an NOE HP mold from a good friend (Thanks RKing) and may take him up on it. I also have access to an Accurate Mold I gave a friend as a gift for his 375 Winchester. I don't remember which design it was but would weigh about 260 grains.
Any additional information anyone can add will be much appreciated.
Thanks, and take care all,
Rick

[rockrat]

Update here too, I have tried the NOE 278gr gc mould and it shoots just as well as the BRP 310. Also, have loaded the 200gr WW bullet over 2400 powder for around 2000fps with great accuracy also

[Whiterabbit]

I’m loading 375 Ruger but it should be close enough. I have not had luck with cast bullets. I can get the speer and barnes bullet shooting OK, got the 270 shooting spectacularly. I wanted to use the gun to shoot the 350 SMK for long range fun and cast for plinking steels. All my loads with NOE cast so far show huge groups. I haven’t figured out the magic combo quite yet for it. I’ll upload the data later when I can so you can see what I was experimenting with.

[rockrat]

What diameter are you using for your cast? I use .379" for my 278Gr NOE boolits. Carnuba blue lube.

[Whiterabbit]

I am using the same mold blank. My mold is the 379-284 mold, 4-cav, flat nose, plain base. I cast with hardball (92-6-2, but the exact mix is loose), and I lube with white label 2700+. As I said before, I'm loading for 375 Ruger so the numbers are probably not a direct carryover. I tried Bluedot and IMR4198 since that's what I have.



If I did not list a group, it's because I was struggling to hit an 8.5x11 sheet of paper at 50 yards, so I didn't bother to figure out the exact number. The gun is built to every standard to be a precision rifle, and shoots clovers with the 270 gr jacketed bullet, so my standards are high for a reduced load, and any bad load is the result of incorrect decisions made at the loading bench, not the rifle or shooter. I consider all these bad. For the record, the group size is calculated by taking the "average radius" and extrapolating that to group size at 50, then doubling the number to be "moa". It's not exact, but at the numbers posted, it doesn't really matter.

IMR4198 was a non starter. I'm not sure I should even bother to try putting less in there. I'm not confident it's the right choice to fill a case to such low levels. You guys correct me if I am wrong, can I put a pinch of IMR4198 in a case and expect acceptable ignition? case fill is supremely low.

Bluedot did better. Here is the data blown up:



While it would be nice to shoot these out to 500 yards, I really developed the load to be a 100 yard shooter. so I don't mind the SD's at all, they won't make a lick of difference at 100 yards. But the group sizes are nothing good. Above 1300 with the loading choices I've made, it is clearly falling apart for accuracy. Maybe I should have purchased a gas check mold. But I think I'm just not "doing it right" to reduce a load in a 375 ruger case to the 1000 fps level. That's 45 colt territory, I feel like a solid reduced load for a 375 magnum should be in the 1500-1800 range, whatever that may look like.

I had other irons to check on, and never revisited this project. Maybe I will in the future but for now I have elected to put my low recoil efforts into other guns.

[Whiterabbit]

If I stare at the data crosseyed and drool for awhile, I suppose it means I should consider 24 grains of bluedot a great success, and figure out what I have to do to the alloy to get it to drive correctly and group. Gas check for sure. But I guess I'd shoot up all my antimony in a hurry if I did that. I picked plain base specifically to make bullet production a more pleasing process.

Other option is to download bluedot to the next node down which "should" be 12 grains. Velocity would be 990-1025 fps range.

For fun, these are my leftovers after the testing

[Larry Gibson]

Whiterabbit

PB'd bullets aren't going to do well over 1200 - 1400 fps depending on powder and that your rifle has a much faster twist than traditional rifles of that caliber (not cartridge). I've been working with a 375248 cast a bit softer than yours in my M70 three six bits. So far I'm having best accuracy [2 moa at 100 yards] with Bullseye and Unique with loads in the 1000 - 1200 fps range. If you want to push above 1400 fps with any accuracy then a GC'd bullet is needed.

[wmitty]

I have a Lyman 378674 pb design, but I immediately started paper patching it and didn’t try a reduced load for accuracy. The two .375 s ( H & H ) haven’t been used in a while; I’ll try and load up some plain base and see if they will shoot accurately with a little slower powder than what you folks are using. Does your .375 Ruger have a 1:10” twist rate? Larry mentioned a faster twist, so maybe a heavier design than the NOE would work for you.

[Whiterabbit]

OK, you guys inspired me. I loaded half of those above to 12gr of bluedot. One shot load. Will see if they group at 50 yards, and catch the ES/SD. We'll see it.

[Larry Gibson]

I have a Lyman 378674 pb design, but I immediately started paper patching it and didn’t try a reduced load for accuracy. The two .375 s ( H & H ) haven’t been used in a while; I’ll try and load up some plain base and see if they will shoot accurately with a little slower powder than what you folks are using. Does your .375 Ruger have a 1:10” twist rate? Larry mentioned a faster twist, so maybe a heavier design than the NOE would work for you.

My rifle is a Winchester M70 375 H&H. It has a 12" twist. The Ruger 375 is supposed to have the same twist.

[groovy mike]

.379 249 grain bullets over 16 grains of Trail Boss work great in my Winchester M70. Same result with 15 grains for Red Dot with half a compressed cotton ball over the powder. My next experiment will be to try the 15 grains of Red Dot without wad or filler.

[groovy mike]

.379 249 grain bullets over 16 grains of Trail Boss work great in my Winchester M70. Same result with 15 grains for Red Dot with half a compressed cotton ball over the powder. My next experiment will be to try the 15 grains of Red Dot without wad or filler.

FYI, it seems to work just fine without the cotton ball too!