[Magnum44]

Agree with wastoute. Spend your money on good upper components. Basic lower components needn’t cost much.

You do want to make sure your buffer tube and lower receiver are compatible. The Milspec is most common but there are commercial receivers as well, and the two are not compatible for tube/receiver purposes.

[FtrPilot]

Basic lower components needn’t cost much.

I would agree with the exception of the trigger. IMHO, a match grade trigger is always a worthwhile investment.

Personally, I recommend the Geissele Super Semi-Automatic Enhanced (SSA-E) Trigger.

SSA-E

If budget is unlimited, then I would recommend:

Hi-Speed National Match - Trigger