I've done a couple KNS pistons before with pretty good luck, but ran into something yesterday. On a Zastava M92 (which was gassed pretty typically for AKs pre-KNS), the rifle would not work on anything but the full closed (i.e. Full gas) setting, and it was barely ejecting at that - in fact, sometimes it would fail to eject. With the suppressor on it, it was great, but I would like to have a little more gas for shooting without the can.
FWIW, I have a JMAC Customs 360 muzzle device on it.
Has anyone see such a "leaky" KNS before where it barely functions/malfunctions even on the "full gas" setting?