The diameter is fine - -
Most all .45 ACP bullets run about .4515 to .452".
I trust you are aware that the old, original, factory load for the prototype pistols was a 200 gr. bullet. When the round was officially adopted for US military use, it became a 230 gr. bullet at about 820 feet per second. All service pistols since have been set up and "timed" for use with such a load.
The pure bullseye target pistols are normally set up for the 185 to 200 gr "soft" loads. All this in aid of the cautionary note: Be pretty careful in using the heavier bullets in a 1911 type pistol. You can easily produced battered parts.
Back in the mid/late 1970s, I was seeking a specialty load for bowling pin matches. shooters loaded the H&G 20 gr. SWC to higher velocity. My idea was to use a lower velocity, heavy bullet, load with increased momentum. I wanted a bullet with a flat meplat and sharp shoulder, to "grab," dig into, the plastic covered pins, to drag 'em off the table. With a round nosed bullet, an off-center hit tended to glance off and allow the pin to spin around and maybe not leave the table. Pins had to not only go down, but leave the table as well.
I loaded 250 to 265 gr. hard lead semi wadcutters with around 5.0 gr. of Unique. Worked pretty well, too. Then I got away from in shooting and went purely into IPSC competition. My loading efforts were entirely directed toward loading ball-quivalent ammo, and I left the heavy bullet ACP loads behind.
My first thought is that you'll have difficulty loading the heavier JHP bullets fast enough to get any expansion at all, using a standard .45 ACP pistol and brass. A .45 Rowland or Super, perhaps? Another consideration is that the already arched trajectory of the .45 ACP cartridge - - If you run a 250 to 260 at down around 600 to 650 fps, it will be even more rainbow shaped. Which said, the broad faced, heavy SWC would be a pretty fair short range defensive load, if you could tolerate handloads . . . .
Best,
Johnny
