As stated above, I can not go into detail with how the Tenko adapter functions. Certainly you are entitled to bring up your concerns. I wish I could discuss in detail our mechanism, but I can't right now. We sent in a proof of concept for a determination. The determination was that the adapter was not a firearm nor did it break any other laws. Based on the proof of concept, we refined the design and added adjustments such that the adapter should function with 95% of all the M10 RRs in the registry. But the same basic function of the 3D printed version was developed in machined aluminum and submitted.
Think of the picture of the RPD upper in a vice with zip ties, angle iron, and a c-clamp holding the adapter together with an AR-15/M16 upper installed. To the FATD, using all of that stuff to get the adapter to fire was the design flaw. So now I need to redesign the system to try to overcome how they made what essentially was a M10 RR from those items. We tested several units with at least 10,000 rounds of use. As far as I know all the testers were pleased with the performance of the adapter. Now they have added an extra hoop to get through. And the "redesign equals a new machinegun" concept will have to be addressed. Thank you for your perspective.
Scott
Manager A&S Conversions L.L.C.