Sunday, June 17, 2007

A great 45 ACP defensive load, or “I finally figured out how to handload with Remington Golden Sabre bullets”

I’ve wanted to see how fast I can push a 185gr JHP bullet out of a 1911. I’ve had tons of Remington 185gr Golden Sabre bullets lying around, but have had poor accuracy with them. Recently, I realized that my loading technique may be the problem. You’ll note that Golden Sabres don’t have a uniform diameter but instead have a 0.2” wide “drive band” near the base, which is 0.451” in diameter, and then the bullet diameter abruptly steps down to 0.441”. This allows the bullet to be longer than would be the case if the diameter was uniform.

I’d been loading to an OAL of 1.220” such that the case mouth ended up just past the end of the drive band and with a fairly tight crimp. Remembering that a 45ACP round headspaces on the case mouth, thinking about this more, I realized that with the case mouth crimped down past the end of the drive band, the diameter of the case mouth was now smaller than it should be for proper headspacing and thus accuracy/consistency would suffer.

I tried an experiment where I loaded to an OAL of 1.230” such that the case mouth ended up just before the end of the drive band, and applied a very light crimp so as not to push the case mouth into the drive band. WHAT A DIFFERENCE!!!! But more on accuracy later.

So, now that I could achieve good accuracy, I experimented with velocity. I wanted a load that would achieve at least 1100fps with a less than +-10fps velocity deviation. I chose Power Pistol (because that’s what I have) and varied the powder weight from 8.2grs to 9.9grs, with a 0.3gr delta. Two velocity sweet spots appear:

  1. at 9.0gr, velocity was 1102.2+-6.6 fps
  2. at 9.9gr, velocity was 1187.2+-9.2 fps

No signs of overpressure (flattened primers, shiny case bases) were observed but past 1150fps, cases were being flung a good 20 feet away, even though I had a 18.5lb recoil spring in my Rock Island Armory 1911.

So, 9.0grs it is. Winchester cases, CCI 300 primers, OAL=1.230”, or seated so that the case mouth is just shy of the end of the drive band, and a very light crimp.

The following is the powder weight vs. velocity curve, with y-axis error bars showing SD in velocity.

As for accuracy, all 40 rounds I fired during the measurements landed within a nice 3” circle. The target was 15 yds away and I was firing offhanded, unsupported, through a Chrony. Naturally, accuracy was not the primary concern here, but even so, a 3” circle is reasonable considering the Rock Island Armory is my “beater” 1911.

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