I have three or four Model 1 uppers, and they work just fine. Model 1 uses E.R. Shaw barrels, which I've found work just as well as a Douglas or other standard production grade barrel. All three of my Varmint uppers (.17 Rem, .204 Ruger, and .223, all heavy barrel) are Model 1. I can shoot one ragged hole at 100 yards with the .223 using a load I developed for it, so it does just fine.