Well I got a BSA SHT 1915 mk1 no111...303.....no scope etc....reliable as all hell...can't take a beatin' and keep on tickin' like a Swiss watch....so when I look at all I have and the possible problems the others can give me being all modern and dressed up I believe the ol'303 gets the nod.
Oops went a little bit overboard on response as I threw in the rifle too.....so of all the calibres....maybe a 7-08.....but if a rifle is included see above.