416 We have at home
HK came out with the MR556A4 - the whole pistol costs $3500. That’s nuts. I was able to find the upper on Rooftop and Sol was offering a discount to beat the HK webshop (super cool). Threw it on a Gen 4 Noveske lower with the Squid magwell. This is heavy but it’s a piston so what do you expect. Paired it with an SBRS print can. New end of the world gun.