What do you think of this? He specifically mentions 3d printed weapons, but he fires his Blank+Slug rounds from a full metal .22 Pistol.

I can only say that I tried this over a year ago with a Y22 hammer. I got a OOB, the 3d printed trunnion (?) broke, the rails broke... it was not fun.

I posted to FOSSCAD about it and everyone told me that the case pressure was too high, by supergluing (I epoxied, that might make a difference) the crimping shut when gluing the slug to it the pressure got too high and basically the back blew off the blank round.

Everyone also said that the 22 "Knall" (blank) rounds were way too hot, and that either powder had to be reduced or replaced entirely with Hilti powder.

In regard to this video, what do you think. Is this a viable round, or was he just successful because he was using a metal manufactured pistol?