Reciever mark 1 unfortunately started developing some pretty bad cracks so I decided to ditch it, switch steels and try again. Second one went much more smoothly. Given that I get all my steel as spares and offcuts from a factory I dont necesarrily know what im working with until I start so these things happen. Needs a lot of smoothing out but the sides are level, the angles are mostly 90 degrees and Its all looking pretty good. Lower shoud be a lot easier as its 1 straight box.