does the 1:9 1/2" twist pose any problems for a 280 cal., is it too fast?
For a 7mm, the 1/9.5" twist is better than a 1/10" , and a 1/9" would be even better, particularly if you want to shoot long spitzers like the Sierra 175-grainer, or a long Barnes X!
I personally believe faster-spinning bullets kill better too, but mosr " experts" poo-poo this idea. I once had a .270 with a 1/9" twist. It killed out of all proportion to its' bullet diameter!!