I have a 280AI and a 6.5-284 built on Husky 5000 actions, small ring mausers, and feeding is not an issue, the gunsmiths had to tweek the feed rails slightly but that was it, they work awesome.
PLENTY FAST ! ! ! I would take advantage of the added horse power and stick with 140gr.+ pills though. I know you said you like to keep shots under 400 yds., but that's just my $.02.So how fast can the 6.5 Sherman push the Barnes 127 TTSX?
Should you ever want to part with that 280 Norma brass please hit me up. Primer pockets tend to be a bit soft, but it is good brass to work with.Got a ton of Norma 280 brass right now, but was contemplating the 155 Bergers and would like to push them fast. So, that RWS might work, if enough capacity is available. Probably have to go back to RL-26.