It is really the length of the bullet that matters but, since no one knows the lengths off the top of their head we usually relate it to the weights. A 9 twist will handle from 32s up to 69gr Sierras, an 8 twist will shoot everything except some of the 80 and 90gr VLDs, A 7 twist will shoot everything except the 90 VLDs but may cause some very light thin skinned varmint bullets to come apart when pushed to a high velocity. If you plan to shoot 75gr bullets then you really have the choice of a 7 or 8 twist. The chrome depends on how much you shoot, if you shoot a lot or just don't clean as often as you should then the chrome is a good idea, there are some 9 twist barrels on the market that are a better quality barrel and can be more accurate when not chromed but, you can't use them with a 75gr bullet.
One word of caution, most of the 55gr fmj on the market is just not that accurate so don't get to bummed when the rifle doesn't shoot them so great, try some 69gr SMKs to make yourself feel better about the rifle.
Last edited by Constructor; 04-11-2010 at 23:28..