Most important
MAINSAIL,
The real question is what do you want the bullet to do?
When I last used a .45ACP, I only used the FEDERAL Hydro Shok 230 grain bullet. It had slightly higher velocity than the standard 230 grain ball loads, but because of the design of the Hydro Shok and its excellent street record, I was confident that it would expand.
Prior to that, I would have gone with a lighter bullet, like the 200 grain SPEER jhp. The early loads were in the +P velocity range, so expansion was guaranteed, but recoil was severe. In my COLT Government model or S&W 25, this was a powerful load, but in the Lightweigh Commander, it had fierce recoil, so I used WINCHESTER 185 grain Silvertip.
Light bullets AND HEAVY BULLETS NEED SPEED TO WORK. The light bullet will be going faster in most cases. In a 5 inch, steel framed 1911, you can count on a 230 grain jhp to expand if it is a decent design, but the shorter the barrel, the lower the velocity. A lighter bullet starts out as a higher velocity, even from a short barrel.
What you have to ask is what you want from the bullet? I want expansion, not only to increase effectiveness, but to limit overpenetration.
A heavier bullet will usuall penetrate deeper, but not always if it lacks the energy and velocity to do so.
The other point is recoil. Small guns can beat your hands up if the recoil is too fierce. I would start with an easy, reliable load like the 185 grain FEDERAL jhp. It had a good street record.
If recoil is not a problem, then stick with FEDERAL HST. The HST was designed as a follow on to the HYDRO SHOK. It should still expand, even at lower velocities. If recoil proves too sharp, then go back to the FEDERAL 185 grain jhp.
The most important thing a bullet has to do is hit the target. If it kicks too hard, then you will not practice enough and you reduce your chance of hitting center mass.
START WITH YOUR LIMITS, NOT WHAT SOMEONE ELSE THINKS IS A GOOD IDEA. PUT CONTROL AND ABILITY TO HIT THE TARGET BEFORE VELOCITY OR BULLET WEIGHT.
Jim