What advantages would a rotary barrel have over standard Glock barrel?
Based on the actual performance of Grand Power, Beretta (e.g., PX4, Cougar), Kel-Tek PR57 and similar designs, the advantages are:
- Barrel stays in line with plane of fire. Arms are generally quite accurate in a similar way to straight blowback pistols.
- Rotating action tends to direct some recoil force as rotational rather than backwards or up. Perceived as tame recoil
- Whether due to the rotating action or other design features, rotating barrel firearms are known for extreme reliability (ref. Langdon 50k PX4 test; "PX4 Storm Tracker" multiple 100k+ tests.) I want their ammo budget...
The 46 design is, if I remember, slightly different but had the same effect. I can personally vouch for the first two benefits.
As for what would sell, will it come here, will it be part of gen6? Maybe, maybe, and no idea. I would imagine Glock are having discussions about how much innovation they need to obtain the sales they want in LEO and commercial spaces ahead of "clones" like RXM or simple competitors. That, and not forum chatter, will probably drive the decision.