For those who may be interested I recently "converted" my 4506-1 to .45 Super. All I did was replace the stock 14 pound slide return spring with an 18 pound spring and use Starline .45 super cases. Works fine..shoots fine..no feeding issues..at least with 9.5 grains of PowerPistol and a hard cast 200 grain bullet.

I have been thinking along these lines for my 4566 since a 1066 doesn't seem to be in my future anytime soon. Any pics of spent casings by chance? any bulged brass or flat primers? Thanks

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It is the Indian not the arrow

That's good to hear. I'm still looking for a 4566, at a fair price, to set up for 45 Super too.

The 18# recoil spring will probably be fine with that loading but I'd think you'd what a little more spring if you go full tilt.

I use a 18# in my 845 but I don't shoot anything hotter than +P (185gr XTP & 9.1gr/P-P) in it.

I use a 22# recoil, & a standard power 20# hammer/main spring, in my 1076.

In my Colt Government Series 70, setup for 45 Super, I load my 200gr XTPs to 10.4gr of Power Pistol. At 10.8gr/P-P bulging cases start in it's not fully supported chamber. 185gr XTPs & 11.3gr/P-P works fine in it too. Primers look normal.

The 1911 has a 24# recoil spring with a sprung guide rod (for extra recoil management), 28# hammer/main spring & a small radius firing pin stop.

Welcome to the forum!

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Waiting for the break of day

I don't have any pics of cases handy but there was NO bulging at all and the primers were still round at the edge. There was some firing pin drag marks on the primer..but minor. I am still using stock firing pin spring and will probably try a heavier firing pin spring after deer season is over. This is my primary deer hunting gun right now.

I am not one to alter the internal works of guns from factory, but I suspect that kind of tinkering can lead to new models later for us all to enjoy.