NEED HELP identifying a .50 BMG antitank gun

[browningautorifle]

If it is a home built, then someone put an astronomical amount of time in engineering and machine work just in building the breech block assembly much less the entire assembly. The transverse and elevating knobs look like military hardware but it strikes me me as something you'd see on a prototype or Mark I version. If an individual built this from scratch they would've been far smarter to copy the transverse and elevation mechanisms from the M3 37 mm,

Agreed on all that. No one said they were being time effective, it was built by someone that had time and many parts to draw from. If you look deep enough, you'll find the guns that every part came from. I'll bet the barrel was originally an AN M2. All parts were scrounged and none designed, just mashed together. I was army all my life, my brother was artillery. They'd never tow something like this anywhere...this thing would be useless. As in no use at all to anyone. The .55 Boys anti tank rifle would be far more use.

Sounds like you want to keep going until someone tells you he agrees with you that this is issue.

By the way, here's a 2 PDR anti tank gun. Way bigger and stouter than this tiddly toy.

The breech looks like it was taken mostly from the Hotchkiss Canon AC SA-L Mle 1937 APX 25mm...and the rest is fabricated. Here's pics of that too...compare the breech mech from this side with your first pic. many differences because almost everything is stripped off, recoil mech, supports...