Before you rule out the rifle because of the 1:38 twist there is some things this twist is very good at. This twist will normally shoot concials excellent. So in this case I would shoot a large full bore conical such as the 460 grain No Excuses. This will take anything down.

That twist will also shoot sabots. A rifle with 1:48 twist will also shoot sabots. A lot depends on the debth of rifling in the barrel. I think the rifle your are talking about would be an excellent rifle....

Also as lonewolf pointed out. Their customer service is excellent. Also if you ever wanted to change to a different barrel twist I believe they sell them out there....