pedal2alloy

You could get a 12ga snap cap. One manufacturer is called A-zoom

No

This is the right amount of wobble:

You should mention which version of the S12 you have, or post a picture of that The people on here don't like to answer questions that you can solve by searching. They are knowledgeable and nice, but a little cranky The angled grooves on that puck go towards the rear. You can experiment using that vs your stock puck The MD 20 is considered the best drum, but the ProMag 12 round is serviceable Search "top round deformation" for all of the info on that I like the DPH adjustable gas plug Last round bolt hold open is not a feature on these guns except for a few special edition ones. But search "LRBHO" and you will find a lot of info

You could replace the mag release lever easily enough. It would be easier than trying to get warranty service out of them

It looks a little loose, but it might be the mag more than the gun. So I would try it out and it might work fine. Also, get a few more mags (which I'm very sure you will do anyway) and see if they fit better

Seems like you could cut a slot in it with a dremel and use a screwdriver

It does seem a little far-fetched, but for the moment let's assume that what you are saying is true. If that is the case, then yes S12 fans would be very interested. The 2 parts that are suspect are the $100 price and the "no modifications necessary"

It looks like a pretty sweet gun

Also, is that 19 round mag made from 2 - 10 round put together?

https://www.gunsamerica.com/digest/vrbp100-semi-auto-bullpup-rock-island-armory/

That pin is supposed to be retained simply by having a tight fit. So sometimes there are loose tolerances in the manufacturing and you will have a loose fit. Especially if your gun is a Catamount Fury which it might be? You want to increase the tightness of the fit. If it is a roll pin (looks like a rolled up piece of sheet metal) you can expand that slightly with a center punch on 1 end, (the end that goes in last) Also, pins should be hammered in left-to-right and removed right-to-left. This is assuming that the gun was manufactured with the normal conventions where friction-fit pins have the holes on the right side slightly smaller. (This is assuming a lot considering where these come from) (and you know what happens when you assume - - - you turn into a complete asshole). If the gun was built this way, it is possible that somebody hammered the pin out left to right and enlarged the hole, losing the tight fit. If it is a solid pin, you can peen the inside of the right side hole of the gun with a punch to close it sightly and give it some tightness. You basically want to take the properly sized pin punch, and go thru the left side hole but then have it sit halfway onto the ledge of the right side hole and peen it around to reduce the hole opening a little bit. Like any type of hammering on your gun, you want it solidly on a bench block that gives support exactly where the pin hole is

It probably has some surfaces filed down on one or more parts of the fire control group. Some guys try too hard to modify everything and just muck it up. So it would be cheap and easy to change out those with new parts and then test it for function. But not with live ammo

The problem was that there was no standardization, so nobody wanted to modify their gun with some proprietary thing if it wasn't going to end up being the standard. The official factory one was on the Russian Spetnaz 030 gun, but those parts were not available and still very hard to come by. Also, it's designed to work with the magwell and not everybody wants to convert to the magwell and modify their mags. It also requires a different ejector block or a modification to the existing one So people would do it if it was a "drop-in" modification, but it is a complicated and involved modification

Also, there are several other after-market pucks available, you don't need to reinvent the wheel. Does your shotgun have the adjustable gas plug in front or the fixed gas block with the integral front sight?