.30-06
After playing around with a few different contours, including the Remington mountain rifle (.550� OD at muzzle) that half-way Sporter contour is about my favorite for a lighter weight rifle. .600 is just about halfway between Remington�s standard .660 and their MR .550 which is why I chose that diameter.
FWIW, the Winchester standard sporter contour for .30-06 and .270 rifles finishes up at .600� OD at 24� which was another sort of influence on the decision. I can't remember off the top of my head all the particulars of the Winchester measurements though I believe it tapers all the way from breech to muzzle.
Gunnery, gunnery, gunnery.
Hit the target, all else is twaddle!
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