Bump the load up to 5.0gr of bullseye and re-test.

FWIW:
That 4.5gr load of bullseye pushing that 200gr lead swc is no where near max anything. It's actually pretty anemic at best. It's so low companies don't even both printing the pressure of that load.

Lyman 49th 452460 200gr lswc
bullseye 4.7gr 775fps -------
reddot 5.2gr 845 -------
ww231 5.5gr 936 14,100cup

The only max load listed in that 49th manual that even bothered to print the pressure of that max load is that ww231 load. Reddot is faster burning than bullseye and lyman has no problem printing use 5.2gr of it.

The 45ar case has more case capacity than the 45acp case.
The 45ar case is just as strong if not stronger than the 45acp case.
Both cartridges are fired in the same firearms.

The 45 auto rim is another 1 of those cartridges that should be updated (along with the 44spl). A company comes out with that cartridge in 1920 and puts a soft lead bullet in it that has a hollow base to be used in the surplus 1917 revolvers that were flooding the market. The cylinders and bbl diameters varied so much on those 1917's they went with a soft bh lead bullet. They didn't want the skirts to blow off those soft lead bullets so they made the 45ar low pressure. It's been that way ever since.

Mold makers have sold hb molds for decades to home casters. A early cramer hb swc mold that casts a .454" bullet for the 45ar or can be sized down to .452" for the 45acp.


That cramer bullet is the 1 on the bottom left. Other hb cast bullets I've cast shot in the 45cal's.


You ought to get some 185gr hornady xtp hp's and push them with 6.2gr of bullseye in those 45ar cases. Those loads are flat shooting, hit hard and there isn't a lot of recoil.