Can someone tell me what the accuracy ranges of the Colt AR-15 carbine (16.1"bbl) LEO model is versus the 20"bbl of the regular length bbls? Is it that big a difference and if so, at what ranges do they really start to differ?   Thanks alot.

Not sure if this will help ya, then again I'm not really sure what your asking.

FWIW, a 16" barrel and a 20" barrel made by the same manufacturer with the same twist rate should (all things being equal, same chamber, same loads, etc..) shoot very close to same group sizes at the 100-200 yard lines. Past there the loss in velocity of the shorter barrel will more than likely creep in and cause group size variances.

Mike

PS - Accuracy, as in groups sizes, will depend on the rifle and the shooter and whether or not your firing a round which your particular rifle likes.