Thanks Cholla, for the great info!
this part is particularly imporrtant, especially for the newer reloader ( emphasis added by me):
this is why it is very important to have access to a chrony; "work up" a load, in small increments; and keep detailed records!
While it is not as detailed and insightful as a pressure trace, This kind of data, as posted by Cholla Hill, gives very good "hints" to the learened reloader about what is gong on. One can also make detailed observations of fired primers, and fired case measurements with a micrometer for further hints.
yhs
prof marvel
I know ya'll don't believe me but I try hard not to re-kindle these old topics ;-)
Cholla, I love seeing your GONG hits.......!!!!!
Unique has been popular in the 44-40 revolvers for a long time. Back in 1930's, the standard max load for
revolvers with 205gr hand cast lead bullets was up to 10.9gr @ 1,100fps @
15,000 pounds of pressure (assume CUP) (approx. 12,690psi) from a 5 1/2" barrel. We all know Taffin and a few others push 12gr for stronger revolvers. I also assume Unique now may be a tad hotter than back then.
Using a PressureTrace II and an MGM 20" 1 1/4" diameter barrel....
7.9gr with a 205 LRNFP Lyman 427098 gave me 1,117fps @ 9,300psi (approx. 11,000CUP) Lyman's 49th Max Load for Group I rifles like the Winchester 73' 12,000cup
9gr with a 200gr Laser Cast Magma BB gave me 1,300fps @ 12,500psi
(approx. 15,000CUP)10.5gr of Unique with a Lyman 427098 gives me 1,470fps @ 18,000psi (approx. 21,000cup)
Winchester's "High Velocity" was 1,600fps @ 22,000cup with a JSPWinchester's pressure's were lower with the .4255 dia. JSP than with larger dia. lead bullets12gr with a 200gr Laser Cast Magma BB gave me 1,635fps @ 22,000psi (could be around 26,000CUP)
Back then, this 1937 data was only used for revolvers while rifle powders, to include Hercules 2400 was used in rifles. Sharpe's 1937 2400 load for 200gr lead rifles was 27.5gr @ 33,000 pounds of pressure...again I assume CUP. Could be around 28,000psi. Certainly not for weak action rifles or revolvers.
Again, today's powder charges may be different, but pressures are pressures...