I ordered a Stiller SA/LH mag bolt face from Greg Young (Southern Precision Rifles) about a month ago. Just got off the phone with him minutes ago to complete the order of my 31" AMU 6.5cal 1-8.4" BBL blank. The 6.5WSM is the caliber of choice here (Norma 270WSM brass), I think it would excel at everything you are looking at doing EXCEPT the tac matches. I feel the 6.5 would toast the throat fairly quickly in relatively few matches (thinking rapid fire).
I also shoot a Lazz Patriot (300 short mag) for hunting, the 300 is going to boot you a little more but a quality brake will solve that. The 300 should offer a good bit of extra bbl life as well, preliminary research suggests the 6.5 will offer better ballistics w/the 130grn CE I intend to shoot but that has yet to be proven
If you are serious about tac matches, go with the 6.5 SAUM or chamber for the 300WSM and run with it.
6.5 WSM would be optimal but may shoot it out quickly in matches.
7WSM would be my second choice but may run into the same problem just not quite as fast
300WSM would be next Excellent caliber i just have one already
I hate to admit it, but the "cool factor" wins ~ 90% of the time with me. I may not need it & I might not be able to afford it... but dang it, I want it!!! Not to mention the allure of the fire breathing, barrel eating, torpedo looking wildcat cartridge that make ALL the girlies go crazy... boo-ya!
Only boy on the block who has one.... Bet your 7wsm can't do that!! lol
I would try a 338 wsm just to be different. Which short action do you have? There is a bit of difference in internal mag length between the different manufacturers. It would be interesting just to see what speed you could push a 300gr hybrid.