Weatherby and Nosler both have them in stock, I would choose one and forget about time and money wasted trying to get the Hornady to work for you, they will have to replace it after a couple loadings anyway.
Welcome to the forum, the 260 is a great cartridge. Its probably my favorite. Ive typicaly loaded mine with a 143 eldx, i have loaded the 129 hornady in a light recoil load for my daughter when she started hunting.
I am looking to start loading up some in the 120-130gr range to use as a deer...
the 143's in my 264WM shoot well, around .5moa with an easy development so could even be better
also shot in my a group in my 260 using my eldx load, if I recall they shot well there too.
The game I'd be starting on is whitetails. And actually over the weekend there was a local gun show and I picked up a another 41mag S&W 657 7-1/2" with a red dot, will add a couple pics later. But this will be the one I'm going to concentrate on for hunting, i do have a box of each the XTP and...