From Clawson’s book
Colt .45 service pistols: Models of 1911 and 1911A1.
(At $1,100 a book, I think I am going to hold on to my copy!)
The original 45ACP load, used in the 1910 trials, and then hencefore for decades was a 230 FMJ with 5.0 grains of Bullseye pistol powder. The specified velocity was 800 fps.
Slower on a cold day, moving about where I expected on a warm. Just like us all.
Rock Island Arsenal GI M1911
230 FMJ
5.0 grs Bullseye (1998 & 2005 mix) WLP, OAL 1.265" taper crimp 0.469"once fired brass
18-Dec-17 T = 58 °F
Ave Vel = 777.4
Std Dev = 14.56
ES = 57.1
High = = 806
Low = 748.9
Number rds= 30
230 gr RMR FMJ
5.0 grs Bullseye lot 907 6/5/05 Mixed cases WLP OAL 1.265" taper crimp 0.469"
27-May-20 T = 80 °F
Ave Vel = 795.1
Std Dev = 22.11
ES = 67.6
High = = 839.5
Low = 771.9
N = 8
Given that powder pressures vary, leading to velocity variations, these old cartridge boxes show early 45 ACP ammunition went 800 fps.
and this was the National Match ammunition for that year. Velocities on the box.
Bullseye pistol powder is the baseline for the 45 ACP, it is still hugely popular in 2700 Bullseye pistol competition because it can be downloaded and it still shoots within the inherent capability of the pistol at 50 yards.
a light load such as what Ernest was using, requires a 12 lb recoil spring for function.
When Bullseye pistol powder became hard to find Titegroup gained a following. Basically I like faster powders in the 1911 than slower. I consider Unique a slower powder. Pressure drop is very important, I don’t know if the 1911 was designed to use the residual blowback effect, as what pressure gauges did John Browning have, but the residual blowback affect is clearly in operation in a 1911. The residual blowback affect uses the last of the pressure in the barrel, to push the case out during unlock. This has to be timed so unlock is under the burst strength of a case sidewall, about 650 psia or less, and won't rip the rim off! You can see from the drag marks, and the soot on the case, that these cases were moving while there still was pressure in the barrel.
Slower powders would be great in things like Thompson sub guns, where the bolt is extremely heavy,
Custom Thompson receiver, upside down
Custom Thompson sub gun bolt
but in my 1911’s, a slower powder such as Unique, or Blue Dot, accelerates the slide more than I like and kicks cases out 20 feet or more. I consider high slide speeds undesirable as I have had slide to frame peening, and luckily the Colt Combat Elite was still within warranty and I sent it back to Colt. They replaced the frame, but did not do anything about the action timing. So I sent that pistol off to Wilson Arms, and they made everything perfect. It is a sad comment that the gunsmiths at Wilson Arms understood 1911’s better than Colt’s gunsmiths.
I adjust the powder charge so I get 800 fps plus or minus, and that load shoots well in my 1911’s. I have a 1990’s keg of AA#5 that I am shooting up. It is a ball powder, the better metering means little to nothing in actual velocity spreads, and the little balls will gum up a Dillion powder horn. I don’t plan to buy new unless I get some dirt cheap, but adjust the load so a 230 FMJ moves 800 fps, and pretty much, it will group in the middle, and function the pistol.
Oddly enough, the last pistol cartridge I'm getting the caliber conversion kit and dies for is......45 ACP. Strange right?
