I’ve been thinking about a way to have a ‘proper’ functioning grenade launcher in my Pulse Rifle for a while. Considering all the various options available which others have explored always had compromises.
Spring shotgun is too few bbs being launched. Mini moscarts are hard to get and would seem to require some disassembly to reload. Gas shotguns usually have the stock as the air reservoir so can’t be cut down (and are expensive).
I got a small 40bb rail mounted gas powered launcher (sold as an HG 138) and managed to carefully modify it and the spas cage to get it functional.
It’s fired by racking the pump handle backwards. Reset involves using a small lever inserted through one of the holes in the spas cage. Gas refill is via a very small hole in the pump handle. The bbs are quick to load as I made a short ‘barrel’ for the launcher which you can just pour a bunch of bbs into and squish them into place.
The fitment is reversible should I wish to go back to the dummy shotgun arrangement apart from the small hole in the pump handle and another hole behind that in the side of the spas cage.
The modifications required fabricating aluminium parts to allow the launcher to mount to the underside of the barrel vent arrangement, a new aluminium ‘crossbar’ at the front and a 3D printed front cap with a wider barrel. A short aluminium barrel, and some modifications to the fake shotgun breech as well as careful modification of the spas cage itself.
The extra weight added (160g) has been offset by the change of the previously aluminium Front cap assembly to the 3D printed version, and changing the 1000mah nimh battery to 1600mah lipo . Total Added weight is 30g, or the weight of a fast food tomato sauce sachet
I have some specific parts on order which when fitted should allow both the firing and reset of the launcher to be carried out via the pump handle.