i posted this originally in the single shot rifles. Has anyone used this combination?
i'm looking for a light load for shooting small deer at reasonibly close range. the trailboss website recommends starting at 70% case capacity and working up to 100%.
Black powder is not availible where i live and i would really like to get my great grandfathers rifle shooting again.
i have Lee 400gr and 450gr bullits availible that i cast, Jamison brass, and a small selection of primers.
Anyone that has used trailboss and the 577/450 MH, i would like to here your comments.

There are several articles in Double Gun Journal from a few years ago by Sherman Bell using trail boss with great results in this round. If I have a chance I'll see if I can find the issue. Bob

i took a chance and loaded 22grs trailboss / 400gr bullet (approx. 70% case cap.) shot 3 rounds. 1 1/4" group at 50yds. (fired quickly, from a make shift rest)
not alot of power, kick or residue.
I'm going to have to try more over a chronogragh from a solid rest to see where i'm at.

The following data was from a 577/450 Martin Henry long lever rifle out of Napal. Is has a 33" barrel with a fine/shiny bore. Brass was Jamison, primer CCI#200 (large rifle), powder IMR Trail Boss, projectile 500gr. lead round nose with no gas check. The velocities were measured by a Shooting Chrony F1 Master Chronograph about 15 ft. from the muzzle and are the average of three shots. The most accurate loads were between 8 and 10 grains. There were no pressure signs in any of the loads and they felt very mild to shoot. Ambient air temp and humidity was not recorded but it was a pleasant spring day so lets say low to mid 70s and maybe 50%(?) humidity. Use this data at your own discretion as no claims of safety are being made here considering the age of these rifles but in our rifle there was no evidence to suggest that these loads were not completely safe.

8.0 gr 617 fps
8.5 gr 662 fps
9.0 gr 680 fps
9.5 gr 782 fps
10.0 gr 789 fps
10.5 gr 792 fps
11.0 gr 825 fps
11.5 gr 822 fps
12.0 gr 840 fps