To second what roskoe said unless you have a custom barrel your gun won't likely group a 64g or 70g bullet. If your guns a 700 I believe all/most have 1:14 twist...they don't even like some of the 55g bullets (I know, I have one. I got decent groups...but I get much better with 50g) Some guys will say that even 1:12 is marginal for a 55g. If you're looking for the ultimate smallbore deer round give the .243 ballistics a look, it's alot more impressive than you might think!