I decided to cut to the chase, and just buy a ready-made solution for airsoft - despite my frequent musings of other options earlier in this thread.
My newly acquired Redneck wheelchair for season 2013 - required due to a less than optimal recovery outcome for double hip replacement procedures in the past few years. 2005 Kawasaki Bayou 250 - a basic ATV, in good nick, and a good price. I'm contemplating a short-barreled SAW mounted upon a home-brewed rack-mounted gimbal mount, next.
The Doctor's advised that i should really think about stop playing airsoft, and take up golf or some other lame-arse sport for exercise instead.. fuck 'em. I ain't dead yet.
