For what it's worth, I have two of Lyman 270 GC one of the was lapped to give a bore riding nose, RCBS 250 GC, Saeco 250 GC, and a NEI 300 grain GC.
I shoot these in a 375 Whelen, matter of fact the rifle has never had a jacketed bullet through it. The best feeding bullet is the Saeco, the most accurate in my rifle, which is really splitting hairs, is the RCBS followed by the NEI and the Saeco.
I found that sizing the bullets to .379, using Rooster Red HVR, with annealed gas checks gave me the best accuracy.
Jim

< Andrew, which NEI mold do you have? I've been looking at their 280 gr. bullet, but I can't figure out which one. They have two, #180 & 180A, that are almost the same. >

It is the 180A.

Actually I use the plain base, .357-265 PB, version with the low loads but the gas checked one should be just as good.

A good long range load is the gas checked #180A with 57gr. of N140 behind it. Gives moa accuracy at around 2200 fps.

This is all from my Ruger No.1 tropical.

OOH! OOH!
Bear Creek Cast Bullets with Soft Gas Checks.

http://www.cliffsgunsmithing.com/Cat_BC375.htm

http://www.cliffsgunsmithing.com/Cat_SGC.htm

I do not usually get all excited about this kind of stuff but once you shoot this bullet with or without the Soft Gas Checks you will see why 375 H&H was pretty much MADE for cast bullets.

And hey, you are in California, come to my shop and save on shipping.

-Spencer

Has anybody loaded plain base cast using Ross Seyfriend's 'nitro for black' 4198 loads and dacron filler. I saw one of his Handloader columns describing a load for the 400/450 Nitro Express using 4198 and a big wad of filler which he describes as funtioning like a gas check. It makes sense and seems it could work well with plain base bullets (of which I have a box of 500 I need to get a decent load going with) at a little faster velocity than using the fast load of shotgun powders. Anybody give this a try yet? Bob