if there using short mag brass then they are going to have to open the bolt up a lot. I know we discussed a WSM wild cat about a year ago and Im still playing with the idea.
I have kind of decided that since im not shooting a AR I dont have to worry about or be confined to AR length rounds. I will just use a 308 length round as is. the 444 marlin will do about every thing all the other new wonder rounds or possably more. dies and reamers as well as prechambered barrels are out there already.