If a long action I would go 280AI if a short action I would go 7 WSM just for the slightly larger case. But I stayed traditional with the AI and a 7RM.
The SAUM could be more accurate but hard to prove in a hunting rifle. Brass is sure a lot easier to find for the AI. If I wanted a real light weight almost magnum then the SAUM would get the nod. What ever you build it will be a good one with those components. Still on the fence about inherently accurate cases but a 30 degree shoulder and a shorter powder column along with a longer neck seem to be the ticket. The 280 AI has all those except the shorter powder column. If you wanted to get esoteric and had to have the 30 degree shoulder then go 280 RCBS.

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