AR uppers are cheaper to replace if you want to change that many parts out. I'd consider selling and replacing. Check out Palmetto State Armory (PSA) or DPMS. I currently have a RRA lower w their excellent 2 stage trigger and a lightweight DPMS upper. Shoots 1 inch groups with my hand loads and 2 inch groups w cheap ammo. Cheapest way to swap is to buy a complete AR and swap parts, sell the remaining gun from the parts you don't want.
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