This wildcat was developed around the 250 gr. Beartooth bullet to give the leverguns something a little hotter than the .375 Winchester.This cartridge will also apply to the short action boltguns.
Calculations show this case capacity is built around 50 grs of IMR type powders @ loading density of .859 of water and the various Ball powders with a loading density of +1.00 of water. Powley says this case capacity with a 250 gr. bullets falls in the burning rate of IMR 3031. So powders like Re7. VV-n134, H322, Ball C2, AA2460, and H335 should hold application. With 50 grs IMR and 250 Beartooth the pressure runs @ 41,000 psi, well within the Marlin's specs. With a 20" barrel the Expansion Ratio is 10 and with a 22" barrel the ER is 11. With this high of ER there is little gained between the 22" vs 20" barrel.The following is loading data:
250 gr Beartooth ( meplat@.245") & 50 grs IMR 3031 = MV @ 2300 fps....ME@ 3013'/lb. With iron sights @.75" high the following is the sight-in data:
Muzzle..Vel 2330'/" & E 3013'/lb, 100 yards...Vel 2044'/" & 2320 '/lb @ +2.00", 200 yards...Vel 1780'/" & 1784'/lb @ -3.6"....At 300 yards there is still 1543'/" & 1321'/lb, but down to -20.3", but this will not bother the boys if they want to "Arc" a round in. These figures change when you go on up to a max of 44,000psi with Ball powder.
As for the jacketed bullet boys...I think the Speer 235 gr would be great in boltguns. I've used this bullet in the .375 H&H mag (loaded down) and the jacket thickness is correct for medium to large game.
Best Regards from The Hammock.....James



(Edited by James Gates at 6:27 am on Feb. 8, 2001)

Mr. Gates,

I think it might be prudent to follow Speer's advice regarding use of the bullet you mentioned:

"Speer does not manufacture a .375" diameter bullet which is suitable for use in a tubular magazine. The 235 grain semi-spitzer bullet can be used in single-shot rifles, or loaded singly in the chamber of a lever rifle. HANDLOADS USING THIS BULLET MUST NOT BE USED IN ANY TUBULAR MAGAZINE." (Speer's emphasis in their Reloading Manual No. 13)

Bill...You are correct..I should have refined my thoughts better. Most of us will use Beartooth Bullets in this cartridge, and I meant to say that for the boys using bolt guns and jacketed bullets, the Speer would work. You will note that I don't work up any loads except for Beartooth Bullets in my workups. Thanks for the pointer!
Best Regards from The Hammock....James