You can cut barrels down indeed, and assuming the gunsmith does a proper cut and crown you should see the same performance as a factory 20" barrel. That said, I really prefer the 18" or 20" barrels unless you're planning to use your rifle exclusively from the bench. The difference between 20" and 24" is HUGE when you're lugging a rifle in the field, and I don't know that the added length/weight is worth it unless you're shooting from the bench at much longer distances. I really like the 20" bull barrels myself and have found them to be quite accurate and still practical for the field.