taschoene said:

The idea of even considering firing 40mmx53 rounds out of a shoulder-fired gun like this seems like a stunningly bad idea.  I wonder if they didn't mean for it to take 40mmx51 rounds, and something got "lost in the retelling" somewhere.

China developed a shoulder-fired launcher to take the NATO 40mm HV rounds (see my web article on grenades). Unless I've missed something, the current western projects are for Rheinmetall's MV loadings.

The relationship goes roughly like this:

40mm LV (180 g at 76 m/s - max 400m)

40mm LV-ER (180 g at 100 m/s - max 600 m)

40mm MV (240 g at 100 m/s - max 800 m)

400mm HV (240 g at 220 m/s - max 2,200 m).

These are ballistic maximum ranges: the practical maximums are about two-thirds of the above figures against area targets, one-third against point targets.

autogun said:

China developed a shoulder-fired launcher to take the NATO 40mm HV rounds (see my web article on grenades). Unless I've missed something, the current western projects are for Rheinmetall's MV loadings.

True, but that has some extensive recoil mitigation.  The China Lake/Airtronic design is literally a pump-action shotgun scaled to 40mm.  With no recoil system, the HV round in particular would be punishing.  MV rounds are manageable (barely), hence my suspicion that the Airtronic mod was to take MV, not HV rounds.

taschoene said:

MV rounds are manageable (barely), hence my suspicion that the Airtronic mod was to take MV, not HV rounds.

I agree.