M3 Sawed-Off Shotgun

Operators:
Brendon "BEARD Actual" Wright
Nick "Hodor" Gilliam

Details:
A number of years back, two of my close friends and teammates randomly bought me a little springer tri-shot shotgun for my birthday. It was a Double Eagle M3 and, as expected, within a couple uses the stock was coming off. I tightened and threadlocked it a few times, but finally ended up simply removing it. Now, as most of you know, the vast majority of the barrel length on a tri-shot is just empty space. One night Nick (Hodor) came over and suggested that we shorten it up to a bit more of a CQB friendly length, but try to do so more tastefully that some of the other hack-job sawed-off shotguns we occasionally see on the field. Below is the final result of that.

Vitals:
Overall Length: 25.5"
LOP: N/A - No Stock
FPS: 300 FPS (with .20g)
RPS: N/A - Manual Pump
Weight: 1,068g

Internals:
-Completely Stock Double Eage M3 Tri-Shot Shotgun [link]

Externals:
-Aimpoint Red Dot (clone) [link]

Builder/Tech: 
Brendon "BEARD Actual" Wright

Build Updates:
All modifications were completed in about 30 minutes of effort.

-The stock was already removed some months before, so that was not an issue.
-I began by using a Dremel to make a rough cut in the magazine tube about half way between the muzzle and the handguard. From there I was able to access the holes to unscrew the front sight without having to completely disassemble the shotgun.
-With the front sight removed, I measured the appropriate length to give the barrel a slight offset from the magazine tube, as well as give enough room to screw the front sight down without interfering with the internal barrel assembly.
-I used a tube cutter [link] that I had from a previous plumbing project to execute a nice even cut on the barrel, then measured off, marked, and drilled the 4 pin and screw holes for the front sight.
-I used the Dremel again at this point to further shorten the magazine tube to the desired length, and (biggest pain the ass part of the build) tapped the screw holes and mounted the barrel/magazine support bracket.
-I then took the magazine tube cap and cut about a 3 mm slit at 12 o'clock and 6 o'clock through the threading so that I could wedge it into the no longer threaded magazine tube and tap it in with mallet. I'm quite confident that it's not going anywhere.

The only real flaw in the conversion process was that due to the fair amount of twist/wobble to the outer barrel, when I measured and mounted the front sight, it resulted in about a 8-10° clockwise offset. Not a huge deal, especially considering the fact this is more of a "point-and-shoot" than "aim-and-shoot" airsoft gun.

Pictures:

The Original Shotgun (for some reason I didn't take a "before" picture):

After modification: