The primary issue he had with his gun (the video from shellgunning) stems from the roller-delayed action system design and the vacuum that is created in the chamber, when the shotgun is fired. What happened with his gun was a function of 2 factors.
1) He was using ammunition that had been stored for a while, resulting in some expansion in the diameter of the shells;
2) the force of the bolt being blown-back creates a vacuum within the chamber that either bulges the heads of the shells, or rips them apart.
Let me explain the second part further...
When the shell is seated in the chamber, depending on the diameter of the shell, it will either fit tightly or loosely. If the shell fits loosely in the chamber (which is more common) the gun will cycle more efficiently. If the shell fits tightly in the chamber, there is a greater likelihood that a vacuum-like effect will occur. Think of it like pulling a cork out of a wine bottle…the greater diameter of the shell, the greater the vacuum pressure in the chamber. When the vacuum pressure is high, the shell’s head can bulge or detach. Obviously, this has an impact on the guns ability to cycle.
After reports of this problem, we developed a solution that would accommodate shotgun shells of slightly different diameter.
Essentially, we etch grooves inside of the chamber of the shotgun so that the gasses can escape, thereby eliminating the vacuum-effect that occurred in some of the shotguns manufactured by SRM, early in its production.
The fact that we moved so quickly to understand a problem with the shotgun, develop a solution, and implement change to their manufacturing process should be viewed positively.
Same issue for the thread on AR15.com. That was back in 2011. As far as the ammo that FPSRussia was using, we are unsure of. The 1216 can be picky and we suggest heavier loads. If we setup that video with FPS, we would have gave suggestions, however, our company didn't contact him. He even made a mistake about saying you can put bean bags in one tube and slugs in the other. We have a special "less-than-lethal" bolt for the bean bags. You can't mix them with live loads.
We have shipped hundreds of 1216's and I can tell you now, the positive reviews FAR out weigh the negative. People are less likely to write a review if they have no issues.
Thanks again.