Trapdoor load question

yblockhead

I'm getting ready to load up a batch of .45-70 for the trapdoor. I want to load with Goex and am loading 350 gr and 405 gr.
My question is, should I go with 2f or 3f and I want to keep the rifle in one piece. Any thoughts or experiences would be appreciated!
Thanks.

cbyerly

Loading for an original trapdoor is more than just assembling ammo. Original ctgs were loaded with powder that was between 1F and 2F. they are all compressed loads. With modern ctg cases, it is difficult to get the full 70 grains of powder in them and still not deform the bullets when you seat them. You must use a compression die and compress the powder before inserting the bullet. The bores of original guns run oversized and the bullets you use should be of correct size for the gun. It is unlikely that any bullets .458 or smaller will give satisfactory accuracy. Lee does make a mold that casts .459. The rifles were designed to shoot 500 grain lead bullets. You will have to install a new higher front sight to get the gun to shoot to the point of aim no matter what bullets you use.

RRConductor

I was given several rounds of original US issue 45-70 ammo, and pulled one apart to see what I could find. Cyberly is correct that it was a compressed load. Although I couldn't tell exactly what granulation the powder was, it certainly looked like 2F.
The most interesting thing was that the 405-grain bullet had a hollow base.
As a result of what I found, I bought a Lee 405-grain hollow-base mold. The results I got from it were so-so, as my bore slugged out to .461 inch. I replaced the base pin in the mold with a larger one that a friend made for me, resulting in a larger cavity in the base of the bullet. Using 55 grains of 2F, the accuracy of the gun improved dramatically.