I have shot thousands of rounds out of Trapdoor rifles and carbines. The bores run large and the barrels are soft steel so jacketed bullets are not the best way to go. The jackets and gas blow-by wear them out prematurely.
Hard to beat the Lee 405 hollow base. They generally drop at .462" I cast them at 20-1 or even 40-1 alloy. I lube mine with a soft lube and set them in .45 ACP pistol trays to let the lube dry a bit so not to stick to the fingers when loading them. SR4759 was the best powder that I found but it is discontinued and my supply is about gone.The Lee bullet has a slight flat nose which does better on deer. Unless you hit bone, they just punch right through deer. They run a bit but leak out quickly. I try and get a load of 1350 fps at the muzzle. If you don't cast check with Buffalo Arms for the correct bullets. Commercial cast of No.2 alloy or wheel weights never did well for me.
You will find that the bullets impact about 8" high at 100 yards. They were regulated for 165 yards. Rifles have a fixed front sight but carbines have a pinned front blade that can be replaced with a higher front sight blade and then filed down for adjusting impact to point of aim.
The 500 grain RN shoots well but I find the recoil heavy.
The Buffington sight is a marvel of engineering. If you notice, it has a slight off-set for longer distances. This was done to compensate for long distance drift caused by the bullet spin. Yes, it was adapted for the 1903 Springfield.
Feel free to reach out to me if I can help.
Last edited by WStrayer; 08/04/20.
