From IvanPrintsGuns:

21:08 – “For a 30 to 60 round use cases, the Biden’s Bane upper is a very attractive option for a build.”.  His initial thoughts.  Keep in mind he was using PLA and firing one shot after another and really heating up the gun in his test.

It’s only a matter of time before 3d printed uppers will be just as reliable as 3d printed lowers.

Thoughts?