Let's carry on right where left off, shall we? I have only four left, but they're all newer, and so they're generally a little more interesting.
So this is definitely one of my more out there concepts. There are these certain gel pens that I liked that had these thick ink tubes in them. I discovered they were pretty much the same diameter as K'nex rods. Then of course I should make a launcher for them, right? As silly as it was, I recall they did have much better flight characteristics than K'nex rods. It used a top loading magazine and a striker that was charged via an open side in the stock, however I didn't quite do a good enough job constructing it, so the back of the striker guide would come apart. Between that and a lukewarm reception, I didn't feel inclined to pursue the concept further.
I don't remember exactly when this was, but I guess it was soon after the Oodassault 2. I figured out a simple way to connect a removable green rod magazine, so I made a simple assault pistol to demonstrate. However, green rods aren't all that great an ammo, so this wasn't all that useful since Oodammo had just become popular, but I figured maybe it could be used on a functioning model.
So this was a nice thought with horrible execution. I had just gotten back into K'nex more seriously during my freshman year of college, perhaps this was the summer. I was talking to another vet member who popped in for the first time in a while. We discussed the physics of K'nex launchers. I won't bore you with the details, but basically understand that projectiles can only be launched about as fast as the striker is moving by the time it hits the projectile. The rest of the energy left in the striker is wasted into the back of the launcher. I thought this was silly, why not try to use it for something? So first idea that came to mind was to use it for a "bolt action" where it did the loading automatically when hitting the back of the launcher. However, this was a pipe dream because I was, ironically, ignoring physics. I was hoping the projectile would've left the chamber before the next round would get loaded. I had never completed the mechanism, let alone test fired it, but I'm pretty certain it wouldn't work. It's a shame because it was otherwise setup to be a compact bolt action if I gave it a manual bolt operation, but it was top loaded instead of with a removable magazine, which I wasn't sure I liked. I've thought of a better system for an "auto-chambering" launcher that should actually theoretically work, but I haven't been able to pull it off yet.
This was also back in college, my third year I believe. I can't emphasize enough how much I struggled to make my own bolt action, but I'd keep trying every now and then. One big self-requirement was that I'd give it a removable magazine. I had the idea for the magazine originating from an evolution of the BAW magazine floating around for a long time but never knew how to apply it. Here was one attempt that made a somewhat compact frame based on the barrel of my Oodassault 3 series. While I had a sear in place, I didn't know how to connect it to a trigger. I disliked the look and the high bore axis (distance between the barrel and the handle) so I didn't try to make it work for all that long.
That's all that I have readily accessible right now. Like I mentioned previously, I believe I have a few more examples on my 3DS, I'll get those someday.