Reloading for the 1873 Dutch Beaumont rifle (Black Powder Cartridge)

by Frank Ambruso @, Saturday, January 18, 2014, 03:39 (2400 days ago)

Dutch Beaumont

Picked up a 1873 Dutch Beaumont rifle last week and have been busy making cartridges out of 45-90 brass.

I am using your typical 45-70 405 grain carbine bullet sized to .458 and a 435 grain Lee gas check micro groove bullet lubed with SPG.

Made some sizing/seating dies out of 45-70 RCBS set that I bored out on my lathe (after annealing) from an old 1870's European drawing available on the web.

The unique part of this cartridge is the sheer volume of the case designed to hold 75 grains of black powder to push its 370 grain bullet to 1400+ FPS, not wanting to push that much blackpowder or smokeless gave me an idea to "Reduce case volume" by inserting an .500" OD x .029" wall x 1.250"" long brass tube into case seated against base and then swaged/retained by the cartridge shoulder when fully sized. The case should now have the same volume as a std 45-70 allowing me to "Reduce BP and smokeless powder loads (24 grains of AA5744 or 22 grains of IMR SR4759) to about 1200-1300 FPS [image] [image] [image]

After shooting the Beaumont Saturday I measured the cartridge cases fired with the anemic load of 22.3 grains of AA57544 behind 405/435 grain cast bullets

The neck measures .488" dia. at the case mouth and .500" dia. .375" down the neck indicating a tapered chamber neck condition not uncommon in these older guns to help facilitate extraction with dirty BP ammo.

Case body has also expanded .005" med length requiring a sizing die polish to "Blend in" the die diameter closer to chamber dimension.

Cast up the Lee two cavity .457" dia. 340 grain bullet (457-340) with 25-1 lead/tin, actually cast .460" dia. 349 grains and I must say this is one of their best molds I have used with consistent quality (visual appearance/weight/release from mold). Bullet base protrudes .341" into the .344" neck before touching lands so it appears this will be the best solution for solving excessive base protrusion into the powder area.

I also upped the charge 2 grains to 24.3/4 grains of AA5744 and added ½” of polystyrene ("Popcorn") packing/filler under the bullet.

Back to the range.

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