Help with build- barrel, gas tube, etc

[Usafa71]

Vascar2 and grayfox- thank you both for the input! Still leaning toward the 18” barrel, if only for the full-length gas system. While I don’t want to “waste” money on a barrel, I do find that quality products are usually the least expensive in the long term.

Since scopes were mentioned, does anyone know of a scope for the Grendel with a BDC specifically for the 123-129 gr bullets?