I was asked to post some pix of my airsoft mods.
Here is the 9 V battery placement, I cut corresponding notches in both shroud halves under the trapezoid to fit a 9v or a 2-AAA pack.
Here is the airsoft barrel with a notch cut for battery clearance, also shown is where I cut the barrel off to mount the barrel extension, I use two 8-32 set screws to force it up and center it in the AS barrel. Alsothe custom blocks I make to mount the grenade launcher. Makes for a nice solid setup.
I take stick batteries and cut the rigid heat shrink off and shrink flexible heat shrink (polyolefin) so that the battery can flex a little so you can shoehorn it into the mag tube of the shotgun.
I'll post more when I have time.
LMK if you have any questions.
M