As far as U.S. made gas pistons go, these pistons are not made using reverse engineering, but instead are made using info given to them by their partners (Arsenal of Bulgaria). They are following the true manufactiring tecniques used by the company that licenses their name, and are adding a bit of extra precision to boot.
Other than them being made with a bit higher precision, the only other difference from the original, seems to be that these are made from solid stainless steel, rather than chrome plated carbon steel.
I'm not currently in the market for an American made gas piston, but if I were, this would immediately be the first one I would look into buying. The Arsenal Inc company products are, (IMO), the next best thing to having the original Bulgarian made components. These guys worked at Arsenal of Bulgaria, they know this design, and they receive all the technical info neccessary to avoid the need to reverse engineer. I would not let the whole "match grade" name thing throw me off. It just seems to be more of their way of expressing the fact that they are employing a bit higher precision while making them.
This whole subject of another component by them, tells me something else. What would that be?..........between K-VAR and Arsenal Inc, they have managed to get one step closer to producing a complete US made AK. Here is what these two componies already produce under license and assistance from the Bulgarians:
polymer pistol grips
polymer upper handguards
polymer lower handguards
polymer buttstocks
forged and milled receiver
forged and milled trigger
forged and milled hammer
forged and milled disconnector
a new stainless steel gas piston
And of course, with permission of the Bulgarians, the right and know-how to assemble AK's in the U.S. (using the licensed name and logo)
Arsenal Inc even has the machinery to make licensed stamped AK receivers.
Whats next?........who knows, but maybe barrels, gas chambers, dust covers, gas tubes, front sight housings, etc, etc :)
With the help of their friends, K-VAR, and their partners in Bulgaria, I could easily see Arsenal Inc of Nevada producing a complete U.S. made AK in quality form :)
That is what I mostly see from this latest news :)