IMR4350 seems to work good in the 270. My question back to you is - Why do you want to load the TSX in the 270? Now just my opinion but unless you are going to use it for elk there really isn't a need for it. I've shot a ton of whitetail and a few mulies and antelope using 130 gr Nosler Ballistic Tips at ranges from literally point blank to 400+ yds. I tried the TSXs in my 270 just for kicks and they didn't shoot as well as the Noslers. But hey, its only my opinion and to each their own. If the TSXs shoot good out of you rifle, go for it. My load by the way is 55 gr of IMR4350 with the 130 Nosler. But a work of caution - this is a max load so proceed with caution.