#####Additional parts needed
* The adapter is designed to use a standard M4 mag catch/latch, spring, and button
* One 8 or 10mm long m4-0.7 'button head' bolt is needed to attach the insert (standard 'cap' head may interfere with mag)
This is a magwell adapter I made for a UTG Mossberg 500 single shot pump shotgun to convert it into a 590M, but it should work with the Double Eagle branded version along with any other makes/models (BBTac, Lancer Tactical, etc) including tri-shot as long as they use the same little sniper style lowcap magazines. The adapter is split into two pieces - a 'body'' which interacts with the shotgun receiver, and a feed tube 'insert' which attaches to the adapter and interacts with the top of the m4 mag. I modeled the part this way for a couple reasons: First, this allows you to replace just the magazine feed tube if it ever breaks (I carry a spare insert but so far no issues); and Second, this allows you to print the insert at a higher quality/density than the adapter body resulting in higher strength where it's needed and a faster print where it's not. I recommend at least 1.2mm walls with 0.1mm layer height and ~60-70 infill for the insert so the feed nozzle is as strong as possible, while for the body 0.2mm layers and ~40 fill should be just fine. An 'alt' body has been uploaded which is more stylized - but also harder to print.
You will need to use supports but be careful - it may be difficult to remove them from inside the magwell if they are too dense. Take care to clean up any droop or sag, particularly above the feed tube insert. Make sure the feed tube hole is clear and aligned when the insert is installed. Minor fitment may be necessary. If you find your m4 mags to not latch in, check if the mag catch pawl/tab lines up correctly - some need a small amount of material removed from the top of the tab allowing it to 'latch' with the mag slightly lower.
Make sure the shotgun's magazine release button pops up when the adapter is installed to ensure the part is locked in place - if not the weight of the M4 mag could cause the adapter to fall out. The adapter is a snug fit by design, but it should lock in with a firm push.
Shown mags are Specna Arms 140rd, MAG VN 100rnd, and PTS EPM1-S Mid-Caps. Also tested with PTS EPM, Arcturus, BlueBox, G&P, Lancer, KWA, EMG, and a few other unknown-brand mags. So far I have not found any that don't work with this adapter.
If you have issues with this adapter please comment and I will try to help!
RM105
