So I have this Bushmaster M4 with a 16.5" barrel and A1 receiver. I want to get a new barrel and flat-top A3 style upper with a flat/picatinny gasblock that I can use for long range varmint / paper hunting. I'll be using it for hunting and at the range with my buds. 1MOA @ 100yd is fine, no more than that is necessary for this project. I have my sub 1/2MOA target rifles for that other stuff.
Ideally a fluted bull barrel would be nice but I'm not sure what length is best for these needs - 20,22,24?. Also, do I want a forged receiver or a machined one?
Tons of options in the AR stuff I know, but the expert advice would be great to hear.

Ideally a fluted bull barrel would be nice but I'm not sure what length is best for these needs - 20,22,24?. Also, do I want a forged receiver or a machined one?
Tons of options in the AR stuff I know, but the expert advice would be great to hear.