Most of my milsurp powders have been used up. Their utility for me has been all over the map, ranging from next-to-useless (#107) all the way to MOST EXCELLENT (fast-lot WC-852 and WC-844). No experience with #105. WC-820 has been about an "8" for me, considering #107 as a "1" and WC-844 as a "10". My lot of WC-820 runs very close to AA-9 in outcomes, which is what Jeff Bartlett indicated. I treated it much like WW-296, only using it in higher-strength applications and starting from 10% below AA-9 data. It has excelled for me with jacketed-bullet work in 30 Carbine (its original "home") and in J-word 357 Magnum loads. It became my go-to fuel for 357 Magnum practice loads using the 125 grain JHP when those were specified by my shop about 6 years ago. Like WW-296, WC-820 depends heavily on "resistance" to do its best work--heavy-for-caliber bullets, jacketed construction, good fit, HOT ignition (mag primers), firm crimp, higher operating pressures. Subtract a few of those variables, and WW-296/H-110/WC-820 will disappoint you. AA-9 allegedly is not so finicky, but I haven't used enough of the OEM stuff to say one way or another. The fuel did fine in my three 357s with the 125 JHPs, matching the Federal #357B "FBI Load" and its 1425 FPS with several commercial 125 grain JHPs. My view--all of these coated spherical fuels can do good work in a narrow window, but Alliant 2400 does just as well in those same venues and has TONS more utility in many other venues and is nowhere near as persnickety or demanding. Finally on topic--WC-820 will not see use in any 45 Colt loads I come up with.
