From my experience, I have a 12 LRP in 260 and it has an alum block. Stock barrel has shot 1/2" 5shot groups and 3/4" all day. I also have a 28" Criterion Bull for it in 260 that shoots 1/2" groups more consistently. Have a 26" LV Shilen in 260 for a model 10 that shoots about the same as the Criterion. Have a Criterion 26" 9 twist LV in 280 Ackley that shoots 180 Bergers 2825fps and 1" groups at 300. Have a McGowen 26" for the 12LRP that shoots 123 Hornadys 1/2", but 130 VLD's 1". All came from NSS except the McGowen. I would rate the Criterion and Shilen as a toss up, both shoot better than the McGowen which isn't terrible.