Just wondering how much weight saving is there between Bushy Hbar and Colt Govt barrel, both 20".  I'm about to buy a brand new Bushmaster HBAR that has been rebarrelled (by a gunsmith) with a Colt govt profile 1/7 barrel.

Is there any accuracy gain or loss, between this and the original Bushy Hbar?  I know the difference between 1/9 and 1/7 twists and that I may loose out in the 55grain, but if saves enough weight it'd be worth it, plus it'd look authentic like the govt M16A2.  Also does thinner barrel wear out faster than the Hbar?  And if it's not recommended to mix Colt barrel and Bushy receiver then please let me know too.  

By the way the price is $575 for the complete rifle, I hope it's not out of ballpark.  Thanks for the information.