The 7.5 mm Swiss ammo is available now, from Graf & sons, but before that, I made it by running a .284 Winchester case into the sizing die. Didn’t even need trimming. Back in the day, I bought a 1911 rifle, 1911 carbine, and 1911 cadet rifle. The cadet is single-shot, has no magazine cutout in the bottom of the receiver, and curiously has a three-groove barrel. Later on, when the 1931s came in, I bought one, and then another a few years later from Aim Surplus, or one of the mail order outfits. The bores were pristine, the sights great (u-notch and post front) and all of them shoot cast bullets superbly for groups.
If you can get one you will be happy with it, with admiration for the finely machined and finished mechanism the Swiss turned out. Their straight pull actions work better than any others, IMHO.