An interesting challenge...

My nearest neighbor asked me last weekend if I could work up a gallery load for his .375H&H Magnum Model 70 using .375" or .380" round ball (he has both). I said I would work on it using what I knew about making round ball gallery loads - which I have for .30-30 and .30-06 - and my library of loading manuals. So far, all I've found are some vague references to Red Dot and Unique powder generic gallery rifle or low-recoil target loads. Generally, any 30-caliber rifle and 8 grains of Red Dot or 10 grains of Unique and a light, soft lead projectile is considered "the load" for small game and close-range targets. Has anyone ever tried such a project? Any thoughts on .375" vs. .380" RB?

FROGO207 said:

Google "Ed Harris the load" you will get more info than you will ever want to read.

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To the best of my knowledge, Mr. Harris never adapted his Load to round ball. I have using both Red Dot and Unique but only in two cartridges: .30-30 and .30-06. But it's a good starting point.

gotboostvr said:

It's been a minute since I've read his article on it, but from memory he was advocating a "standard weight" cast bullet for the cartridge (i.e. 150gr for 308/30-06) over a dash of RedDot (8 or 9gr if I remember).

I openly wonder, a round ball would weigh less, which typically requires less power to reach the same velocity and the larger 375H&H case means you'd normally need more powder to reach the same velocity... about 8 or 9gr of RedDot would probably be about the right starting point.

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Thanks for the tip, Frog! Harris made the point that 2400 is not position sensitive and that was one of the reasons he chose it - based on Mattern’s testing. Red Dot and Bullseye also tend to be position insensitive but not to the same extent as 2400 - but TiteGroup is less position sensitive than either RD or BE. I may suggest we include 6-7 grains of TG as another starting point in that massive cavern of the .375H&H’s case with a .380” round ball shaved into the neck and crimped at mid-point to avoid set-back.

This is going to be a lot of fun!

jmorris said:

I’d likely try trailboss. Have used it for cast 150’s in a 308 as backyard plinkers, 2” @ 60 yards, no recoil, not much noise. Personally I’d just as soon shoot a 9mm 147 from a rifle but I guess we all have to play...

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Two problems: First, the neighbor wants to try roundball and its his request to make the loads; and, Second, I don’t have any Trailboss.

nofendertom said:

I have tried round lead balls and Unique in a 30-30. The problem was crimping the case on the lead ball. I used cast bullets for light powder puff loads.

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For .30-30, I bell the case mouth to .311/.312 using a Lee universal expander die (you can use an OD mic' and subtract 2x case thickness OR use an ID mic' to verify - I use an OD mic') and - literally - "drop" a Hornady .32 round ball (actual diameter .315 depending on where you measure - use the widest circumference) into the bell, press into place so the mid-point of the ball hits the rim of the case (approx. 0.158" exposed lead) and put a drop of red Loktite (JUST a drop) on the rim and roll it around the edge, coating the entire surface where the crimp will impact, and crimp - don't let it dry on the ball before crimping. It holds tightly enough for the single-shot Contender and gives a nice, pleasant "pop!" when fired. POA at 50 feet and tends to group about like a cylinder-bore 12ga. at the same range.

Will a similar method hold tightly enough to feed in a Winchester 70's magazine? We'll find out.

Edit: Forgot to mention I use a Lee FCD to set the crimp.