I've loaded and shot a lot of reduced loads in larger capacity  cases over the years and found powders that work extremely well for these purposes. Some are not very position sensitive, and even when playing with muzzle or cartridge pointed downhill prior to firing, they still ignited consistently.
I use mostly H4198 for larger cases and reduced velocities, but also Unique for pretty light loads. Both work extremely well.

Poorhouse wrote on Jan 23^rd, 2023 at 7:30pm:


4198 has lower chamber pressures than BP has!

I have made reduced capacity 45-70 cases by putting a toothpick down into the flash-hole, and adding a weighed amount of eutectic alloy.  Then setting them on a hotplate until the alloy melted.  Drill out the toothpick.   

They didn't seem to help with reduced loads.  I have since used amaranth seed filler for reduced loads for BP, and found it to work fine.  Meters very nice with ordinary powder measures.   They are hard seeds about 1mm diameter.  Cheap at health-food stores or on-line.

CHRIS

I planted some amaranth seed about 10 years ago and man do they produce!!! I have them all over the yard now. I was told some foreign countries grind up the seed for flour to make bread.

I also just recently tried amaranth seed after "oneatatime" told me about it for my .50-140 Sharps 1874. I really needed to reduce the powder charges to make this big boomer tolerable, and it's working out great!
I was a bit hesitant the first shot fired, and was shocked at how mild the recoil was! I finished off the box of 20 rds. I loaded, and went home and upped my powder charge about 15 grains of Swiss 1 1/2, and reduced my filler accordingly. Still very tolerable recoil, and I will likely continue working up loads to see how accurate I can get them, and still have recoil levels I can tolerate.
I have my old Lyman 55 set up just to drop amaranth seed filler. I bought mine online from some health food store and 5 lb. bag was under $15 with free shipping. 
My bore looks pretty clean after firing, and I see nothing on the ground out in front of the bench. I do notice the burnt seed smell at each shot mixed in with the BP smell, but it's pretty mild smelling, and other shooters tell me it smells better than straight BP!

Mal wrote on Jan 24^th, 2023 at 7:48pm:


I have an original Rolling Block Sporting action I rebarreled with a Green Mountain .40 barrel in 1:16" twist, and chambered to .40-65 also. I shoot H4198 at 23.0 grs. with a 420 Snover bullet, and it's very accurate out to 1000 yds. No fillers and my own lube mix.

Mal wrote on Jan 26^th, 2023 at 4:46pm:


Not familiar with either of those numbers? 
I have an 8 lb. jug of IMR4198 coming soon, so should be set for awhile.