Help with reduced loads in a 375 RUM

[Tripplebeards]

I have a couple of boxes of .375, 235 grain Speers I’d like to load up for whitetail deer. Ive tried trail boss and the groups were horrible. Like 12” plus at 50 yards if I remember correctly. I didn’t have any luck with accuracy till they got up to speed with starting loads (2800 FPS plus) with normal powders. Don’t remember the powder I used at the time. Anyways, it got pretty stout for recoil when accuracy started getting acceptable. I have since changed out the Vias muzzle brake (that didn’t help with recoil)to a KDF brake. I haven’t tried it yet since the KDF was installed. The vias quiet brake would recoil about the same, or worse, than when the brake wasn’t braked. Shot a couple of deer with 260 grain accubonds around 20 years ago. Two shots, 2 deer, and a bruised shoulder. Man that gun belts my shoulder!!! I’m not recoil sensitive but that gun punishes shoulders. Would like to use the gun for deer without getting knocked out of my tree stand and get sone use out of a gun that just sits. Hopefully the KDF is more forgiving. I have a KDF on my 300 RUM. It recoils like a 243 with 125 bullets loaded at 3,950 fps. Any suggestions on powders and downloading my RUM? I did check my action screws today. They were probably hand tightened to 12 inch pounds at max. In sure back in the day they were probably the same torque because I didn’t own the wheeler wrench then and just tightened by hand. I torqued them to 35 inch pounds. I did bed the action and floated the barrel before my test groups but didn’t have the screws torqued properly so that could have had played a part in the horrible groups. I have RL22, rotumbo, h1000, and imr 7828, and trailboss for big bore powders.

[Tripplebeards]

I do have a bunch of 2230C and a little Unique as well.

[Larry Gibson]

If you want velocities in the low 2000 fps range none of those powders are suitable. You need something in the range of 4198, RL7, 3031 and H4895. Note; none of those are a ball powder.

[Tripplebeards]

Thanks Larry. I figured about as much.

I thought I read 2230c was ball? I never opened the jugs after I bought them to find out.

[Larry Gibson]

Yes, 2230c is a ball powder. It is excellent for 62 - 70 gr jacketed in the 5.56, with bullet of 155 or less in the .308W or 30-06. Other uses with light to medium weight bullets in other cartridges. It is similar in burn rate to AA 2460 but that doesn't mean it is a gr for gr equivalent. Like many ball powders it doesn't ignite and burn efficiently with reduced loads in large cases.

[Tripplebeards]

I looked in my cast bullets Lyman 4th edition cast bullet handbook. No 375 rum listed but 300 RUM and 378 Weatherby was listed as well. Figured they would be close to case capacity to get an idea of what powders and similar load data that would probably work in the 375 RUM. I’ll have to post a photo of the load data of both. What confuses me is both have loads listed with powder charges in the 37 to 44 grain weights. They sure aren’t going by the 60 % or higher case capacity rule. I believe my case holds 111 grains if I remember. The load data in layman’s cast bullet handbook is more like 30% to 40% capacity fill. Sounds like a catastrophic failure waiting to happen?

[Texas by God]

IMR 4198 works just fine for reduced loads in the .375H&H and I'm thinking that it would work in the RUM as well. It ought to make that young cannon more fun to shoot!

Sent from my SM-A716U using Tapatalk

[Tripplebeards]

This would at least give me a similar idea of powder charges imo since they would be comparable case capacities. I’ll have to call hodgen to confirm. Don’t have any of these powders on hand and and my LGS of course has none in stock either.

[wmitty]

You can certainly kill deer with the speer 235 gr.. but the Hornady 220 grain would probably serve you better with the reduced velocities the cast loads shown provide. Certainly I understand using what you have and I am sure the speer at 1800 -2200 fps will get the job done…

[Tripplebeards]

I believe the hornady 220 grain was discontinued sometime ago.

[1006]

Sierra makes a 200 grain 375 bullet, but it is hard to find. This guy sells some lighter 375 bullets:

https://vollmerbullets.com/

I have not used them, but am planning to in the future for my 375 Winchester.

[Tripplebeards]

I have 200 of the 235 grain Speers so that's what I'll be using. Is there a reason why I'm being suggested to use a different bullet? Are the 235 grain Speers to heavily constructed not.to open around 2000-2200-2500 fps on thin skinned game? Got the bullets to use in my 375 rum for thin skinned game. Did I pick the wrong bullet?

[1006]

Shorter bullets of lighter weight have always given me better accuracy when using reduced loads. The barrel rifling might stabilize them better at the slower velocity, and the recoil will be reduced while maintaining higher velocity.

[15meter]

Did a quick pass through LoadData, zero cast boolit data.

Kind of surprised at that, I would have expected at least a few cast loads. I know they are way fun in a 375 H&H. And there is a bunch of cast data for that cartridge.

[GooseGestapo]

Unique will accomplish what you’re wanting to do.
I used Unique to fire form some .375Ruger brass I was making. I was surprised at how well it shot.
I too have used the 235gr Speer, and I also found that accuracy improved as I approached top loads. (In my case 2,850-3,000fps with Reloader15).

With Unique, I was using the Lee .378” 255gr cast bullet. The mold cost less than a box of 50 jacketed bullets! I started at 10gr and worked up to 16.0gr. No where near a max load but as fast as I needed (enough pressure to fill out or obturate the brass case to my chamber).

The Speer bullet is “kinda” tough as it was intended for the .375 H&H originally as a light big game bullet. It went through the 140lb 8pt I shot with it in ‘12 and dug a divot in the ground 4-12” deep and 10’ long after hitting the deer. Impressive actually!

I prefer the Hornady 225gr PtSpt. A little bit more accurate and easier to find an accurate powder charge.
The powder you’re looking for is Acc5744, also sold as Shooters World “Buffalo Rifle” powder. IMR4759 which was discontinued recently (again!) is also the old standard for reduced jacketed and mid-velocity cast bullets.
And, of course there is my favorite #2400.