First not-totally-crap polymer lower?

[discreet]

The problem is that companies take a part designed to be made out of aluminum, and substitute plastic, without modifying the design to take into account the properties of the material it's being made out of. A piston won't fix that. A piston just gives you a new set of problems, different than your old set of problems, plastic lower or not.

The reason it doesn't make sense to build on another platform is because you end up having to build the entire gun, not just the lower. Ain't nobody got time fo' dat.

A piston in a gun like a SCAR or ar18 relocates moving mass to an entirely different point. From there there doesn't need to be any conventional receiver extension design thus eliminating the main weak point of polymer lowers. That was my point. That is why the Scar lower handles so much abuse as well, as it's not in anyway a point of major stress as by design all the stress is un the upper it's self.

Same thing with the Masada etc. Issue is the conventional ar15 system and bcg just isn't polymer friendly due to the enherant design of weight moving so far back past the receiver further stressing that thin/smaller part of the receiver.

Unless the polymer lowered gun offers something really different, such as folding stocks, ambi controls, and supporting a matched upper with different system and quick change barrel etc, there really isn't a point in using polymer to begin with. The cost savings now are so miniscule. I really have no idea why new polymer lowers are even coming out. It's nothing like the polymer pistol market. You don't see people trying to push polymer 1911's, you see them pushing glocks etc. New design new gun rather than trying to reinvent the wheel.