Thanks for the comments on mid-work, guys..
.. Et (pretty much) Finit.
I still have to remove and paint the rear mods, but that will be done at another time.
Photo's show the front mount finished - first and second photo shows range of elevation of the gun mount (it ain't an AAA gun, so higher elevation isn't really required - keeping to the higher ground is of benefit for a vehicle not worried about air attack
). I can increase the elevation range with additional filing of the front mount, but we'll see where we are at with that after the first game to see whether the present setup is fine or not. While the butt-stock fits fine between the handle-bars, it isn't really meant to be used on the move - it's more of a 'travel to location and assume a static blocking or guarding position off of the ATV' type setup.
Partial ingredient list for the project was as follows:
Various bits of aluminium plate, tubing and flat/bar/boxed stock.
Satellite TV mount base.
2 x HD corner desk cast-aluminium re-enforcers for the front mount arms, re-purposed and modded.
repurposed M203 RIS mount and 2 x swing swivels.
All in all, about ~70 hours into this, with basic tools consisting of assorted files, hand drill and drill press, jig-saw with metal blade, and hack-saw.. nothing more fancy than that. My lathe decided to sh*t the bed through lack of use these past few years of idleness, so i went back to the tried and true hand-tool methodology. Oh, and a lot of patience was beneficial, too.
As above, the additional front mount is a "keeper" mount .. it keeps the gun from going anywhere as the ATV bounces about, as well as controls the vertical range of motion. I did this also, to keep the main portion of the mount from stressing the stamped sheet metal of the box magazine cradle - without the keeper mount, the box magazine cradle would be resting against the main pintle/pole mount.
Now, I guess i should actually get around to replacing that bad King-Pin on the front end of the thing, that needed replacing when i bought it 4 months back .. repairing just ain't as fun as creating.