Don't count the 200gr .358 bullet out before you try it, remember Precision Rifle sells one. I don't own a .45, but I have tried the duplex saboted version in two different .50s. It did not shoot well in my Omega (no keyholes, just big groups) however in the old Traditions 1:28" inline I had it shot 1-inch 100 yard groups.
Every barrel is different. All you can do is try it. I'd try it and load it hot.
It'll be awhile before I get the 265s tested, I'm too busy to shoot for a couple weeks at least.
Modified to add --- I've been a fan of the 200SW for years (since it came out??) although its light weight starts to become an issue at the furthest ranges I shoot. The 325gr matches it in drop, with twice the energy and less wind drift. If the 265 is accurate at max powder charge as well, I'll have a decision to make. It is supposed to have a SLIGHTLY higher BC than the 325, and will be moving faster, so once I have the numbers I'll have to check wind drift. Drop is easy to calculate, it's wind which screws with longer shots more. It'll come down to determining the best compromise between drift and energy I think, I don't see either bullet winning all the cards.
The problem with Dead Centers has always been their lack of a jacket -- they are a great shape but when you're limited in the power you can put behind them, they start to lose their advantages.
