Cold hammer forged unit will give you the most practical lifetime, and the DD is the best priced (though the BHF are also great looking units).
I'd say the DD and BCM Lightweight 16" units are going to be the lightest (.625 @GP), and for the value they keep up great. If you're going to run it really hard, then a Centurion or Noveske Rogue Hunter could make sense, but even the BCM non-CHF is a great barrel.
Given the existing DD Content of your rifle, the DD Lightweight seems like the simplest option anyway.
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Semper Fi
"Being able to do the basics, on demand, takes practice. " - Sinister
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