Cartridge: 500 Linebaugh
Firearm: Converted Ruger Blackhawk, 7.5″ Mag-na-ported Barrel
Primer: Winchester Large Pistol (WLP). It is gold colored, which helps identify light loads.
Most of these weights are based around Lee Dipper sizes, because it’s faster to use a dipper than to setup a fancier measure. The high bulk of Trail Boss makes me feel comfortable with the less precise dippers, because variations in volume don’t matter as much.
Good Everyday Load
Bullet: 420gr Hunter’s Supply
Powder: Trail Boss 2.2cc Lee dipper ≈ 9.4grains ± 0.2
Primer: Winchester WLP
LabRadar series: 81
Shooting Record: 5 shots, 4/11/2017 @ Sunnyvale Rod & Gun, between 8 and 9 PM
Velocity: 768 fps
Spread: 778.6 – 757.4 = 21 fps
StdDev: 8.12fps (5x)
Drag Coefficient: -0.56 fps/yard over first 60 yards
Notes: Recoil was very controllable, no pain at all, I could make 100 yard hits repeatably. Winchester WLP primer helps identify light loads.
Although very slow, 420 grains × 768 feet per second = 240 grains × 1,344 feet per second, which approximates 44 magnum factory ammunition. And there was much less muzzle blast than with a 44 magnum. I was fortunate enough to be able to setup my chronograph at the 100 yard steel, and the LabRadar indicates that velocity-loss was very good for a pistol – order of 1 fps lost for 6 feet of travel.
I only got data to 60 yards. But extrapolating to 100 yards, the slug would still be moving at about 710fps — still a “Power Factor” of ~300. With such low drag, it should hit harder than the hypothetical 44 magnum at distance!
I had good luck by taking Missuri Bullet Co .54 Roundball (actually .528″ diameter, advertised Brinell hardness 5) running them through a .5115″ sizer, charging cases with a a 1.9cc dipper of Trail Boss (about 9.8±0.2 grains), putting in a fiber wad, seating the sized-ball lightly and heavily crimping to hold it in place. I used Win WLP primers as with all my light Linebaugh loads.
LabRadar series: 154 (Steel target at 25 yards)
Velocity: 822 fps (789, 854, 773, 790, 889, 811, 857, 814)
Spread: 116 = 889-773 fps
StdDev: 40.38fps (8x)
Drag Coefficient: -2.3 fps/yard at 811fps
Notes: Very smelly. Smokey and dirty. Not match-grade accuracy, but they made a well-defined group on steel at 25 yards (I’d estimate 6-10″ couldn’t measure or get a good picture before closing time). Certainly good enough accuracy to show a flinch, and only $0.14 each!
The round ball shape has a lot of drag. A pure lead ball would weigh ~200 grains.
Ultimate Bullseye Load
I highly recommend Fury Custom Bullets. It’s a one man shop that lives up to it’s credo: “I MAKE THE BULLETS YOU WANT BUT CANT BUY“. I was able to get 300 grain swaged wadcutters, knurled (to hold tumble-lube and bump the size up to .512”) and gas checked. And at a very good price!
With a 1.9cc dipper of Trail Boss, seating totally flush with the case mouth, and taper crimping lightly (500 S&W taper crimp die). I got:
LabRadar series: 155. Steel target at 25 yards, last shot missed (100 yard backstop but data implies hitting the ground at ~51 yards)
Velocity: 741.36 fps (772, 760, 733, 752, 724, 708)
Spread: 64 = 772 – 708
StdDev: 24.05 fps (6x)
Drag Coefficient: -2.7 fps/yard at 700fps
Notes: Leaves HUGE clean-cut holes in paper. At over half an inch they can be a real advantage in some rules. Recoil is very heavy for a bullseye load, but no pain without gloves. I have not yet figured out a consistent charge.