I have a distant family member who has a 375 Ruger but is afraid to shoot factory loads due to some recent surgery. I would like to load 235 to 250 grain bullets pretty slow so he can at least shoot this gun. His family chipped in and got it for him for Christmas not realizing he can't use it. Any suggestions are appreciated.

Trailboss? Easy to determine load, mark the case where the base of the bullet will be and then fill with Trailboss to the level marked. Weigh the load. That is your max Trailboss load, take 70% of that weight and that is your min Trailboss load. They loads will be very mild to shoot.

Hornady makes a 220 gr FP for the 375 Win that would be great with the Trailboss...Sierra makes a 200 gr.

You can always go with a gas checked cast bullet but you need to chase the web for that, plus you might search around on the cast bullet forums for someone to sell you cast bullets.

Midway has a nice selection of 375 cal bullets.

QL lists 28.0 for a 100% load with a 235 gr Speer SSP #2417, 3.30" COAL, ~1700 FS/1500 FTLBS

Horn 220 #3705, 28.1 gr T.B., 3.10" COAL, ~1760 FS/1520 FTBLS...

Sierra 200 gr #2900, 3.1" COAL, 1840 FS/1500 FTLBS...

Basically turns your 375 R into a 375 Win.

These are all 100% fill loads, pressures are in the 33KPSI +/- a couple thou.

I probably wouldn't go below 20 gr on the low end...just my thing...I haven't used T.B. in too many cartridges AND ALWAYS GONE WITH THE RECOMMENDED AMOUNTS. It did work well for my loads.

Luck

This is info that Accurate/western powder co. Emailed me for reduced loads.

Powder: Accurate – 5744.
Bullet weight: 200 - 230 grains.
Low load: 40.0 grains (2075 – 2175 Ft/p/sec)
Maximum load: 48.0 grains (2350 – 2450 Ft/p/sec)
Bullet weight: 250-260 grains.
Low load: 37.0 grains (1900 – 2000 Ft/p/sec)
Maximum load: 45.5 grains (2200 – 2300 Ft/p/sec)
Bullet weight: 300 grains.
Low load: 35.0 grains (1800 – 1900 Ft/p/sec)
Maximum load: 43.0 grains (2075 – 2175 Ft/p/sec)

Enjoy.

hodgodn h4895 is working well too ...

https://www.hodgdon.com/wp-con...uced-rifle-loads.pdf

i use 25 gn of IMR 4227/H 110/ win296 300 GN CAST BULLET @1500 FPS...very pleasant and mild to shoot...if you used a 250 it would be a real pussy cat to shoot
Daniel

I built a few of them early on..I used RL-15 exclusively, once I figured it out..It bested the 375 H&H by a little and was very accurate..I don't recall the expact grainage, but I got the loads from a gun magazine. A reloading book should have RL-15 loads. just use the book starting loads for mild loads or find a good lead bullet load at about 1900 FPS would be nice for up to deer.