This my knex assault rifle I built.
It is mostly my own design, although I would like to give credit to Jamalam, as he and I both coincidentally came up with the same slider mechanism shown on page 3.
It has what is referred to as a 'true trigger', by which I mean a trigger design which holds back the firing pin/bolt rather than blocking the ammo, which would pose a decrease in firing momentum. My design allows for momentum to build up in the firing pin before striking the ammo.
Quite a bit of trial and error put into the designing of this weapon.
Step 1: Barrel
Just build everything as shown, you need alot of gray/blue spacers.
Note: 3 little blue spacers = 1 bigger gray spacer.
Step 2: Handle/trigger Assembly.
It's a bit tricky, but I tried to make it as thorough as possible.
Sorry for any blurriness, I forgot to switch to the close-up focus feature for some of the photos.
Step 3: Firing Pin Construct
Build the firing pin.
Step 4: Clip/Magazine
Here you will make the magazine. Mind you, it's not exactly interchangeable.... yet.
Step 5: Stock
The last part is the stock.
Step 6: And That's It, Have Fun.
A few tips:
+When pulling back the firing pin to reload, do it quickly, as slow movement will sometimes cause it to jam up.
+Put no more than 6 or so blue rods in the mag at a time.
+You'll have to experiment with different rubberbands on the firing pin. I've found that two to three work best, but the size will matter too.