Cartel DIY open-bolt automatic .50 BMG rifle

A simple 3d model based on a bizarre find by the Brazilian police in Rio de Janeiro from the local cartel, a massive DIY open-bolt automatic rifle chambered in 50 bmg, supposedly meant to be used against police helicopters but its usability and practicality is dubious at best. The Cartel DIY open-bolt automatic rifle was constructed from the looks of it from sheet metal and pipes welded together to form a crude luty esque rifle. The fact that the rifle is chambered in a cartridge like 50 bmg and is fully automatic while being shoulder fired means that it will have some absolutely brutal recoil when fired. The guns practicality gets even worse as you take a close look at its constructions and function, the gun operates under simple blowback open bolt mechanism which mean that for a gun like it to work it has to have a devilishly heavy bolt and recoil spring which will worsen the recoil and having a really stiff spring also means that most likely means that the rifles bolt cannot be manually cycled easily, this means that to cycle it you most likely have to disassemble it.

Type - Anti-materiel rifle.
Action - open bolt simple blow back.
chambering - 50 bmg.
Feeding mechanism - 10 round box magazine.
Cyclic rate - most likely fast, too fast.
recoil - too much.
Making this model was rather difficult as there are out there barely any info or pictures of the gun and the 2 pictures that I could find show the rifle in an weird angle from which it was difficult to see the shape and sizes of specific parts so I had to eye ball everything.