Anyone us an RCBS 37-250 mould?

[JD2]

I would really like to find out what diameter the RCBS 37-250 mould casts. I'm going to be loading for a 38-55 with a .379 groove diameter. I like the style of the 37-250 bullet, but I'm not sure that it will cast a large enought diameter bullet to match a .379 bore. I guess I could always use the RCBS 378-312gr mould.......

Any imput would be greatly appreciated!

[45 2.1]

I have both, two 37-250s with the big round grooves cast about 0.3775". I've heard of the 37-250 with wide bands and small grooves that cast at 0/379". The 378-312 casts about 0.3785". We need someone to make a mold the right size besides LEE.

[felix]

It seems the a lot of us on this board object to having a boolit made too large in diameter out of the mold. I can understand that for the smaller diameters, but not for the 30 calibers on up. It is not hard to include more lube space to satisify the anticipation of sizing the boolits down. Just have to keep in mind the amount lost by the sizing operation. Sizing from 460 to 452, for example, is less than 2 percent reduction, hardly any difference to the eyeball when there are multiple and fairly deep grooves existant. Sizing a water dropped boolit within 6 hours of being made will not have any hardness loss worth talking about. ... felix

[Bullshop]

Jd2
I have the RCBS and I dont think(memory)it will go that big. I have the Lyman GC and PB (older ones) and they will go .379". My gc version will even go .380" The RCBS is a good accurate design and you might lap one to gain a couple .000" The 300+ gn boolits can have twist issues with older guns haveing 1/16" twist. I have a roller in 38/55 with 1/14" and the Lyman 330 has a little wobble that shows up as increased drop and drift at long range. Dropped a little length with an NEI 320gn and JR used it in some long range events and kicked butt out to over 800 yds. At Amadon ND they had a 600yd T-rex that was tough, and young sharp eyes mad Dad look, well lets say he out classed me. Gotta love it!!!
BIC/BS

[Pilgrim]

My 37-250 casts right at .376, or perhaps a touch under. The weight (WW + tin + touch of magnum shot) is ~270 gr. I know I was concerned about it being too small in diameter for my .375 Win. BB. It turns out it shoots just fine. I'm still dinking around sorting out my "final" load for this bullet/rifle combo, but ~2000 fps with a 270 gr bullet ain't too shabby. I'd have to go back to my notes to be absolutely sure as I've not worked with the rifle for upwards of a year, but I believe the load is using W680. FWIW