The Roles and Weapons with the Squad

[Compost]

I haven't seen this sort of solution in the works, but it sounds interesting. Over the shoulder has worked well for one of the most prolific weapons, the RPG-7 for ages.

The residual difficulty with over the shoulder recoil for a 40x53mm HV barrel is the need for a correspondingly taller bipod. But that would be preferable to having the barrel recoil in a tube that extends under the butt to pass below the shoulder.

This seems to fit your description fairly well except it is not over-shoulder.

35mm QLZ-87 is an interesting weapon with its full auto presumably usable only when tripod mounted. That site also reveals that China went on to develop a 35mm QLB-06 semi-auto with ergo features well suited for use by light infantry. Their projectile weight is likely to be less than that of 40mm LV and MV ammunition but higher than that of the XM25.