Originally Posted by
ASH556
Jerhelo, do you have a full-auto lower? Are you running a silencer? Do you want to shoot match ammo for MOA or better accuracy beyond 100yds?
If the answer to all of those is "no", then buy a lightweight barrel. If the answer to any of those is "yes" then consider a different barrel.
I am a proponent of a lightweight barrel on a carbine. It makes it much more pleasant to handle/carry. Heat/accuracy loss are non-issues for a weapon with a 2 or 4MOA red dot shooting 3-4 MOA ammo. Based on my personal experience, a hot Lightweight Daniel Defense barrel will still hold 1.7 MOA with match ammo.
Also, Trident1982 on this site has done some testing with a LW DD barrel. You can find both of our posts in the semi-auto precision forum.