I think that Pull Bolt is pretty cool!
Similar to the AR even...
I'm with you on that worst design. That doesn't look great at all.
As far as another worst design? I don't like lever action guns all that much. (I killed my first deer with one) They jam if there's any dirt, grime, muck or if you don't work the action fast enough...but not too fast. I see a lot of problems with it. I jammed the thing like 4 times in one day of deer hunting. The only Lever Action gun I've ever bothered to use was a .45 Colt Cowboy Repeater-type rifle.
Just not my preferred design.
I like Bolt Action and Semi-auto. Burst is good for the Military but not Civvie guns I think. Full Auto is good if you know your way around, what to expect, and how to handle it.
Now concept that didn't take off...
I'd really have to think on that one. There are many things that never took off but I don't know if you would call them innovations. I know there's one that is cool that
did take off is the way that certain guns are made to incorporate magazines from other weapons....like the Sten and NATO weapons. Everybody uses the 30 rd. STANAG magazines now.
The Sten was designed to be able to use magazines from the MP-40 so if they captured enemy weapons, the ammo wouldn't be useless to them and they wouldn't have to use the enemy's weapon. I'm not sure if that was the
exact reasoning behind it...but that's how I see it.
I read something somewhere that you should never trust your life with a weapon that is not your own. You don't know how the enemy kept their weapons and the last time they were cleaned...not to mention you might not be familiar with that type of weapon.
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I remember the time I did the US Army Laser Marksmanship training at Fort Knox. That was before I knew my way around the AR platform. It seemed so overwhelming at that point (but I was also like 10 or 11...that probably had something to do with it). Now, I could pick the thing up and feel perfectly comfortable with it and I now know what all the controls do and how it works.
The one I didn't figure out was the M249 and the M240. I was confused by those....but it was also kind of dark in that room. I don't know if you're familiar with that kind of training. It's a simulator they set up with lasers and pistons in the guns that register on a computer. They run you through qual-type firing and scenario stuff...and of course...we have to have our fun by including the extras...like the Turkey Shooting...and stuff like that.
They had a good setup. M16A2's (or maybe a 4. I don't remember. Probably a 2 though.), M249, M240, AT4, M4A1 with an M203 fitted (that was fun) and they all were fully functioning weapons. They could just take the special components out and lock and load with real ammo IIRC. It's been a few years since then.
Here's a picture of what it looks like: (The room is dark...the camera flash makes it look like they have lights on)
That's not the same setup I had...and those look like A4's.
That was one of the coolest things I've ever done. Later that day, I got to go do the Stryker Driver and M1 Tank Driver simulators on the base there.
Loved it...it's up there with me flying the Gyrocopter last September.