[Robert357]

I think that the BAFT fear is that serious hobbyists can finish an 80% AR-style lower for personal use and that a 50 Cal rifle is something that they want to keep a little more control over. But that would be political not technical.

Recoil is also kind of an interesting issue. Not sure how a typical AR-style low end lower would hold up under the recoil of a 50 cal. The shoulder stock need to attach to the lower and even with a great muzzle break that is probably a lot of kick being transferred from the barrel/bolt through the lower into the shoulder stock.

[Manly Warrior]

Point one- ATF control over a 50 cal upper- agree with that idea, the AFTE is deep state to the hilt, Trump has not dealt with them as needed. The entire DOJ is rogue in my opinion.

Point two- the AR lower bears no recoil impulse in regards to structural requirements. The buffer tube/receiver extension and the upper rear face transfer all recoil, the take down pins simply hold the lower to the upper.

Using a decent brake ( witch in a light weight 50 cal is a given) felt/free recoil is not much more than a 12 gag 3 inch mag load- maybe 45-50 ftlb, less than a 416 Rigby or 458 Win in a similar 8-9 lb rifle.