I still haven't had a chance to actually play with it, but I've been tinkering with mine quite a bit. This includes smacking it and twisting it to see just how resilient it is (though what I've done far exceeds the abuse I'd actually expect it to survive from the way I play, particularly given how it is positioned).
The good news is that the thing holds up just fine. Being smacked sideways with enough force does result in it popping off of the body, but even tumbling through the air and striking my floor from standing height does no visible damage to it. Keep in mind that the force required to actually knock it off has to be aimed just right, and required winding up for a forehanded slap. You'd have to break your ass to generate enough force to get it to pop off in a game, unless your opponent was sneaky enough to come up and b*** slap your marker. That is to say it stays on just as it should, but is also super straightforward (though requires a bit of force) to take off.
I've also been feeding balls through it and testing the side to side movement, but there don't seem to be any issues with feeding. The movement is really minimal, too, maybe 1-2° of rotation. It always looks like it's right on center.
The only "shortcoming" is the totally understandable absence of threads to receive the CCI feed tube. Hence, you're basically cutting threads into the plastic with the CCI feed tube. This works for a while, but I worry that over time the plastic may stretch or these cut threads will wear a bit, particularly if there is force applied to the back end of the feed tube from side to side or up/down. The quick fix appears to be using some epoxy to fuse the feed tube to the mounting bracket.
the cci tube is tapered as is the area the tube is threading into, so that would limit some of the concerns.
but I do see what you are saying especially if you are threading the cci tube in and out a lot.
not sure of a remedy for that yet. might not need it.
Overall all, this is an amazingly simple and sophisticated way to make any ULE mag stock class. It looks awesome and works exactly as it should. And it's feasible that you could yank the thing off and put on a feed neck/hopper in about 20-30 seconds, making it VERY easy to switch between stock and open class play formats between (or even during) a game.
In terms of functional improvements, there aren't really any obvious ones for the core functionality of the product (read: it works exactly as it should). Some added features that would be interesting to consider might include:
• C clips on either side to hold 10 rd tubes
• Dovetail on the top to accommodate mounting a sight of some sort (armson pro-dot maybe?)
these items can sure be added to the design. also working on incorporating into the design to be able to just shove your 10 rnd tube in, and have that be the feed.
From a cosmetic perspective, it fits in really well with the functional design factor of AGD. I would imagine it could come in a number of colors, but black suited my needs perfectly. The only cosmetic shortfall comes from the 3D printing process, where you can see the bead lines pretty clearly and there are a few places where the surface gets quite rough. However, this is easily remedied with some fine grit sandpaper for those that think such things are necessary.
as those where prototypes I printed them as low res as possible, if/when these become avail ill print in a higher res to reduce the visible layers and such issues.
I too will be making arrangements to purchase the kit KNM sent me, and I'll be looking forward to see if he also comes up with a version that accommodates the cram-n-jam approach to stock class play.
Also a PS for those thinking about warpless feeds: The thing can easily be flipped the other direction (so the feed is facing forwards) like a longbow/qbow adapter. This could make it an excellent candidate for warpless feed options as long as there was a 90° elbow available. That said, two 90° elbows that close to one another may make for some chunky feeding, especially if the distance between them wasn't tuned. KNM's bracket isn't a true 90° corner, it's more of a curved tube, so there's a bit of comfort there.