375 h&h

I have recently traded into a winchester model 70 375H&H, I have been wanting to try paper patching for awhile and this seems like a good place to start. I have read through some of the stickies and have some questions for you all.
Can you recommend a core mold for 375 that throws a boolit between 275-315 grs?
I have a fair amount of ACWW+2% tin already smelted down in ingots also have some 50/50 ACWW and Pb ready to go can I expect decent accuracy with either one or both of these at say 2500 fps or above once I perfect my PP technique?
Would like to PP so I can get jacketed speed or close to it without the cost of j words, am I wrong in thinking that way?
I am not new to casting I am however very new to PP its an itch I’ve been wanting to scratch for awhile and I may be wrong but I see the 375 as a perfect opportunity to try it out

I run full pressure loads with paper patch with little issue. I have a swage die that produces 348 dia bullets. Patched up they have worked great in 375 Win Contender. I haven't shot them in the H&H yet, but I don't anticipate any problems with it working.

Thanks Badger, have you pp any boolits with lube grooves? I’m looking at a couple different moulds from accurate molds was wondering if I just bought a mold that threw a .378 boolit and sized it down .010” then patched it back up, or if I should opt for a dedicated slick sided pp mold.

I have a 30 cal 170 grain mold made for paper patching. They cast 300-301 and seem to be working ok. It is a grooved bullet. I think I'd get a mold that would throw .365ish for paper patch. Grooved bullets seem to patch fine, but I have never had a problem with smooth sided bullets either. Most of the paper patch bullets I use are swaged except for this 30 cal mold. If I had the right size die, I'd swage it too. Ideally, your projectile prior to patching should be size on size with your bore. (a sliding or tight fit) . I think you will be pleased with the results.

Finding one that drops at 375 might be difficult. You want gas check or no? Lyman, RCBS , everybody makes a mold for 38-55. Most will be on the lighter side of your range. Depending on your advice, you might want to try some 368's for the Europeon 9.3mm stuff. You might try posting on the bullit swap section here. I have lots of them but currently out of stock.

If you get a dedicated PP mould, buy one about .002" over bore diameter that has the little tumble lube type grooves. I find this works best for smokeless PP. As mentioned, 9.3mm moulds throw bullets that usually work in 375s with no changes, just patch them up.

Waiting to see it it groups worth a darn with slow velocities. My 375 RUM wouldn’t hit a barn if locked inside of it with trail boss loads and 235 grain jwords. It started grouping half way decent, but still not acceptable, with bare minimum starting book loads that would still rip the average persons arm out the socket.lol. Wondering if a .003” over barrel slug diameter would improve accuracy? Imo too much powder wasting in that big case to find out.

Many moons ago I was in Big Horn Trading, which was always interesting. I found a few, new, in the box, Mark X barreled actions chambered in both 458Win and 375 H&H. Marked $300 and some dollars, one of the 375 H&H's went home with me. I put on a Bell & Carlson stock and Burris low powered variable scope and had some fun with it. Then, I thought Hmmm, called LBT and we discussed a PP bullet. Soon a 285grn pointed two cavity mold with slick sides showed up. It also had a teeny tiny boat tail. Well ....OK. The two cavities were the one PP bullet and the other was a GG-GC bullet of the same weight.

I cast and patched some and quickly found it really shot well. An even 60 grains of IMR 3031 would shoot into 3" at 200 yards and do almost 2500 FPS. I have no idea the diameter of the casting. I shot a cow elk with it and have not done anything with it since. I can go measure a bullet if there is any interest and I can find one.