The conversion to .45 Super requires a fully supported chamber, (no Glocks) heavy duty recoil and firing pin springs. I shoot some .45 Super in my Ruger, but my gun's forte is the handloads using .45 Super brass from Starline. Even with the heavy recoil spring your frame to slide contact is substantial, so if you are in love with your .45, do not mistreat it in this way for very many rounds. The Ruger P90 is a natural choice for experimenting with .45 Super. It is inexpensive, the springs from Wolff are cheap, and it is fairly accurate; more so with the hotloads than with the generic target loads for some strange reason.
In the P90DC, the recoil spring increases from 11 lb. stock, up to 16 lb. for the heaviest. There is no rating on the firing pin spring, but it is stiffer than the stock spring. My local gunsmith just built a 1911 on a P14 frame, chambered .460 Rowland. he used a 32 lb. spring in it.
By far the best option is the Springfield Long Slide V-16, chambered for .45 Super... that is, if you want to buy a new gun...
YMMV,
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.45 Super... Fat and FAST...
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