Sounds as if one great big bill of goods has been sold to some misinformed believers! Sleeved barrels are nothing new and were tested among the precision rifle shooting community over 20 years ago. Since that time they have been reintroduced and tested time and time again yielding the same results - not so good. There is absolutely no advantage to sleeved barrels with the exception of weight reduction - period. The rifle bench rest community clearly found that not only accuracy was not improved but conversely it diminished with sleeved barrels due to an interference with harmonics. Testing results of handguns (when using standard mechanical accuracy testing fixtures) have shown that absolutely no improvement in accuracy has resulted. However, it was not diminished as with rifles barrels merely because the impact upon barrel harmonics is reduced with shortened barrel lengths. I would wager, however, that there may be a negative impact upon an 8 3/8" or longer barrel. Unquestionably whether or not a barrel is sleeved has nothing to do with the throating, chambering or fit and alignment.