I'm thinking about driving these at 2000-2050 FPS in a 375 2 1/2. Deer and pigs are the intended game, will they expand at all? Thanks.

Get some wet newspapers or magazines and find out. Then you can tell us.

when the hole starts at .375" on deer and pigs, expansion isn't really necessary.

As an aside, I did use my 375 H&H on deer on year. I used a 300gr. Partition at 2400 fps. Based on the wound channel, I'd say the Partition didn't expand. That deer however went down so fast in the fading light I thought I might have missed. When I came out of recoil the little shooting area was completely empty...the deer went straight down.

I think you are going to be fine.

I use the Speer 235s primarily for load development so haven't shot anything that was alive with them. that said, my experience with them into various backstops has indicated they are very susceptible to expansion. Most of the recovered bullets I have seen had impact velocities of at least 2500 fps. slowing them down by 400-500 fps should still be quite sufficient for them to peal back- it may even retain the core at the reduced velocity, which is good.

Received a note from a gentleman who has used them at 1800 FPS with good results. Moderate expansion judging from the exit wounds, retained cores, no jacket or lead fragments and thru-deer penetration according to him. Looks like I'll be loading some up and off to the range. Thanks for your time and advice Gents.

Drive them as slow as you want, lots of hogs killed with such a bullet in pure lead, a 375 doesn't require expansion on deer and hogs, and you can eat to the hole...I have shot deer and Javalina with 235 Speer bullets at 1500 fps. without any problems, but I,ve shot maybe a hundred Javalina with a 22 L.R. and deer also on our ranch in Mexico back in the 1940s and 50s...Its not the bullet its the placement and knowing your capabilities at what range.

Ray, Thanks for the advice, your opinion is always appreciated.
Best.

That performance level is similar to that of the 375 Win. You will likely have better results using bullets designed for that calibre, like the 200gr FN or the discontinued Hornady 220 gr FN bullets.

very soft bullet -- results should be great

You can download the lighter .375 bullets to 30-06 or even 30-30 velocities. I've done it with the 235gn and 200gn bullets.

Some years back, Handloader Magazine even ran an article with handloads for pet cartridges downloaded to "deer hunting" velocities, and the .375 was one of them.

As everyone stated I'm sure you will be fine, I test a lot of bullets in milk jugs.
I usually line up 6 milk jugs or Laundry detergent jugs full of water and shoot them at 100 yards.
I know water isn't same as a deers body but if it penetrates20-30" of water and the bullet doesn't shuck the jacket then it is a pretty fair indicator that it will plow through and exit a deer.
Another plus is it is always fun to shoot water jugs!

no worries.
the 375 super mag revolver is running under that speed and the bullet you want to use performs in it just fine.

A heavy cast bullet works great on deer at 1500 to 1800 FPS. drills a 375 caliber hole, kills well, leaves a good blood trail if they run a ways..I have a friend that uses his 375 and 416 Rem. with heavy cast flat nose bullets on culling operations..Ive seen many kills by him. about perfect...

I suspect one could use a North fork or GSCustoms flat nose solid or maybe better would be the North Fork cup points..they would get just a bit of expansion perhaps..

I have shot a lot of African Plains Game with flat nose solids and cup points at very fast velocities with little meat damage and they killed good, but penetration in your area might decimate a portion of the California population! not that's a bad idea, but would be unpopular!

Thanks for the information gentlemen! I had planned on using the 220 Hornadys but they are hard to find now. The rifle is a commercial Martini allowing me to use any nose profile and I have a good supply of the 235s. Ray, I'm about to order a RCBS 250 gr gas checked mould, cast with wheel weights it should come out about 260-265 gr, I expect it will more than do the job if I run them at 1800-1900 fps. Thanks again to all, great to be able to tap into such a broad base of knowledge.

I have cast hundreds of bullets using the RCBS .375 FN 250 gr bullet. Mostly I use wheel weights or lead scrounged from the impact areas of a rifle range (the lead is good but smelting it to get the dirt out can be a hassle). More recently I've used Lyman #2 alloy or different brands of the generic mix. I've used the bullet for deer hunting, but have not been able to find one within range when I had it (a 375 H&H loaded with SR4759 to 38-55 velocities. But I'm sure it would have been very effective- if the deer would have just kept up their end of the deal.

the Lyman 375449 sized to 379 is just about universal in the various 375 rifles.
I use it in the 375 lever guns, and in the 375 H&H.
it's a titch heavy for the revolver so I use either the hornady's or the sierra's I have squirreled away.

Sounds like a plan to me..Im sure it will work out just fine.

Did a quick trip to the range yesterday to try some initial loads. With a Lyman cast GC WW bullet weighing 280 gr average I'm getting 1740 FPS avg. With the Speer 235 I'm getting 1839 FPS avg. Accuracy was good for both considering my old eyes, certainly good enough for deer at 100 yds. I think I'll stick with the cast load and maybe try to get the Speer 235 up another 100 FPS to the mid 1900 range. Again, thanks for all the great thoughts and advise.
Best.