Drawing for RCBS 375-250?

[Hogpost]

I'm a black powder lever-action shooter & pig hunter. The RCBS 375-250, crimped to the first grease groove, gives me max powder capacity and cycles perfectly. Unfortunately, my mould drops too small for the .378-380 dia I need. I'd like to try a custom mold: eliminate the useless crimp groove, expand the diameter, and maybe try it without the gas check (illegal for CAS/SASS and not really needed for BP velocities)

Does anyone have a drawing of this bullet/mould, so I have a starting point?

[Tom Myers]

I'm a black powder lever-action shooter & pig hunter. The RCBS 375-250, crimped to the first grease groove, gives me max powder capacity and cycles perfectly. Unfortunately, my mould drops too small for the .378-380 dia I need. I'd like to try a custom mold: eliminate the useless crimp groove, expand the diameter, and maybe try it without the gas check (illegal for CAS/SASS and not really needed for BP velocities)

Does anyone have a drawing of this bullet/mould, so I have a starting point?


I don't remember the origin of the data so I can't vouch for the accuracy of the dimensional values but this is the data I have on the RCBS 37-250. You are welcome to use the dimensions to create a bullet .
Hope this helps.

http://www.tmtpages.com/LinkSkyImages/Sketches/R.C.B.S._Mold_37-250-FN_252_gr_Sketch.Jpg

[Hogpost]

Cool! If this isn't absolutely perfect, it is so close as makes no difference, and makes a pefect starting point. Thank you, Tom!

[Nobade]

You might want to look into getting a Lee 38-55 mould. Mine throws a .380" boolit and should work very well in 38-55 leverguns.

[DonH]

You might want to look into getting a Lee 38-55 mould. Mine throws a .380" boolit and should work very well in 38-55 leverguns.

.380" with what alloy?

[Nobade]

.380" with what alloy?

Stick-on wheelweights usually. It's about all I ever use with black powder cartridge ammo.

[Bent Ramrod]

I had the same problem and went to the Accurate Molds website. They have a design that duplicates the standard Ideal 375248, a 250-gr plain base flatpoint, which can be ordered in whatever diameter is needed. I asked for a cavity that would cast 0.382" for a grossly oversize Highwall barrel. Got exactly what I asked for; it casts, looks and shoots great.

My gun's chamber is similarly cavernous, so there was no issue with chambering a round with such an oversize boolit. You might want to wrap some paper around your present boolit, make some dummy cartridges and see how large a boolit diameter in the shell will still chamber in your lever gun.

[Hogpost]

I use 20:1 or 30:1 alloy depending on the gun and what I'm shooting, but zero antimony ever. The soft stuff slugs up nicely in some wierd old European guns I have, and expansion is perfect. My '94 Win barrel slugs at .378/379, and will chamber up to .381 easily.

I'm sure I can buy an existing mould, and I thank you guys for the suggestions. Unfortunately (?!) I'm an engineer and so prefer to design something of my own, even if it's just a modification of an original. Besides, the RCBS has been ideal for my purposes; I just need it to fit the barrel better, and maybe tweak it here or there....; heck, experimentation is the fun part!