I' ve used similar devices dropping my .30-06 down to 7.62x39mm, but it' s kind of worrysome since the auto round is .311" and a .30-06 is a .308" , plus, the accuracy isn' t really good. I can' t really picture those sleeves being great unless they are bbl tubes, since the bore would be so much larger than your wads, bbl tubes work good, but for the money, you' d be doing as well to shoot the proper ammo, since the price of the tubes would be more than the extra price of the ammo.