Reloading for the 1873 Dutch Beaumont rifle

[Frank Ambruso]

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

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.

[Frank Ambruso]

Case expansion
After shooting the Beaumont Saturday I measures the cartridge cases fired with the anemic load of 22.5 grains of AA57544 behind 405/435 grain cast bullets

The neck measures .488" 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 about 2 grains to 24.3/4 grains of AA5744 and added 1/2" of polystyrene ("Popcorn") packing/filler under the bullet

On the Beaumont, I finished up forming the balance of the 47 cases (lost three in forming) this time with .035" wall brass tubing inserts vs. first 30 with .030" wall tubing inserts so will be ready for the 200-500 meter military rifle silhouette match this coming week.

The annealed inserts are swelling/forming slightly to inside of case walls under the 22.3 grain AA5744 /poly fill loads evenly around internal circumference of case, only one slightly loose one that did not fireform to case.

Recently read that someone was using up to 25.5 grains of AA5744 with unsleeved cases and 400 grain bullets, I also noted that my load was mapping a little on the light side to the sight settings( +100-150 meters) to the 200 yard target distance. Im thinking of upping the 22.3 gr. charge to 22.5 gr. with the 386 gr. spire point and watch pressure, primer, case/insert expansion signs changes with this older action.

2 MOA seems to be about the best to expect from this rifle based upon small sampling of rifles/shooters on the web so ill try to meet and maybe exceed that for the match hopefully centered on the targets, wind drift values/mapping should be the real challenge not having shot my 40-65/45-70 sharps or highwalls in a couple of years beyond 200 yards.