Originally Posted by larson1122
There's a few pictures here that might help show the difference: http://www.m4carbine.net/showthread.php?t=41436
I agree, it is not a necessity, just thought I would throw another option out there to consider. The OP mentioned maybe adding a scope and the HBAR would give a slight increase in accuracy, even though that increase isn't exactly substantial.
That's a great short thread. Pictures of the barrels and the slight accuracy advantage of the given HBAR. Also mention of 1-9" not stabilizing the heavy bullets well.