This instructable is to show k'nex ideas so that others can try to build them. They are going to be mostly weapon ideas.

Sections

Step 1- Ammo Feeding
Step 2- Triggers
Step 3- Barrels
Step 4- Firing Pins & Pulls
Step 5- Grenades
Step 6- Guns
Step 7- Miscellaneous Weapon Designs
Step 8- Miscellaneous Non Weapon Designs
Step 9- Real Life Weapon Designs
Step 10- Concepts In Progress
Step 11- Stuff That's Been Done
Step 12- Completed concepts

If you have any questions, would like a more detailed explaination or more pictures for a peticular design please ask.

Each picture corresponds to a letter and 2 numbers, the first letter is the section, the first number is the picture number, and the second number is the design number.

Similarity to any other design is coincidental. If you use any of the ideas from Knex Concepts, you must give the designer credit for their idea on the intro step of your instructables and slideshows.

Tell me if you post an instructable using one of these concepts, if you successfully construct one of the concepts, I will rate an instructable including it five stars.

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Step 1: Ammo Feeding

1A1: Staircase Hopper: This hopper uses 90 degree angles instead of a funnel so that ammo cannot jam. -by Oblivitus (credit to cj81499 for the visual)
2A2: Hopper Revolver: This design uses 8 straight line hoppers (which are jam free) on a revolver to conserve vertical space. -by Oblivitus
3A3: Horizontal Magazine: This mag stores ammo in a line parallel to the barrel and turns it up through a curve into the chamber for firing. -by Oblivitus
4A4: Auto Feed Magazine: This is a new mechanism that will release a loaded mag upon inserting it into the gun. This picture shows the magazine before insertion. The green lines in the picture are elastic bands. Read the note. -by Oblivitus
5A4: Auto Feed Magazine: This picture shows the magazine after it has been inserted. Read the note. -by Oblivitus
6A5: Non-Interlock Magazine: This magazine feeds one round into the chamber at a time to prevent the grooves in rods from locking together. Interlocking k'nex rods reduce power so this magazine will be more powerful than others. -by Oblivitus
7A6: Detachable Mag Handle: A pistol with a detachable handle that is also a magazine. -by Oblivitus
8A7: Thin High Caliber Mag: A blue rod magazine instead holds yellow rods at an angle to save space. -by Oblivitus
9A8: Tilted Horizontal Mag: Rounds would be pushed along by an angled mag pusher. This design saves space and therefore increases capacity. -by Oblivitus
10A9: KKAR: KillerK's new ammo magazine. This magazine allows lots of ammo in a small space, and was inspired by the Peacemaker Carbine from Bulletstorm. -by TheFoofinator
11A10: Spiral Drum Mag: Drum mag with two rods that rotate in one direction to push rounds to the outside of the spiral and into a firing chamber. -by Oblivitus
11A11: Layered Drum Mag: A drum mag with multiple layers that fill the entire space within the drum which both rotates with an elastic and is pushed up by an elastic. When the outer layer is emptied of rounds, the drum moves up and the next layer begins emptying. This layer changing would be achieved by making the rounds press upward against a flat surface on the gun. -by Oblivitus

Step 2: Triggers

1B1: Full Auto Trigger Mech: This is designed to be used with a motorized or elastic spun machine gun. This picture shows the mech with the trigger pulled. -by Oblivitus
2B1: Full Auto Trigger Mech: This picture shows the mech with the trigger released. -by Oblivitus

Step 3: Barrels

1C1: Spiral Barrel: This is a barrel designed to add spin to a round of ammo to increase accuracy. It is constructed with 4 flexible rods, 2 running side by side on 2 sides. -by Oblivitus
2C1: Spiral Barrel: This picture shows how a round of ammo would move through the barrel. -by Oblivitus

Step 4: Firing Pins & Pulls

1D1: Auto Reset Pull: This firing pin pull will snap back inside the gun by an elastic band after being cocked. This picture shows the system before cocking. -by Oblivitus
2D1: Auto Reset Pull: This picture shows the system during cocking. -by Oblivitus
3D1: Auto Reset Pull: This picture shows the system after cocking. -by Oblivitus

Step 5: Grenades

1E1: Shotgun Grenade: A new grenade idea. The bottom must be heavier than the stick barrel so that the grenade lands correctly. Read the notes. -by Oblivitus
2E1: Shotgun Grenade: This picture shows how it is thrown. -by Oblivitus
3E1: Shotgun Grenade: This picture shows the grenade hitting the ground and firing. Read the notes. -by Oblivitus

Step 6: Guns

1F1: Slide Action Slingshot: This is a magazine fed slingshot gun that pulls elastics (the green line in the picture) and hooks them onto the trigger mech by pulling back a slide. Behind the mag, the barrel gets smaller than the ammo so that only elastics can be pushed into the trigger mech. The elastics are pulled along the ceiling of the barrel so that they will slide over the gray connector currently in the chamber. -by Oblivitus
2F1: Slide Action Slingshot: This picture shows the slide, the two blue bars in the barrel are the elastic pulls. -by Oblivitus
3F1: Slide Action Slingshot: This top view picture shows how the elastic pulls would be inserted into the barrel. -by Oblivitus
4F1: Slide Action Slingshot: This top view picture shows how the slide would sit on the barrel.
5F2: Mag Fed Shotgun: This is a shotgun fed by four magazines set up side by side to fire four gray connectors each time that the gun is cocked. This front view picture shows how the magazines would work. -by Oblivitus
6F2: Mag Fed Shotgun: This side view picture shows the basic setup of the guns parts. -by Oblivitus
7F2: Mag Fed Shotgun: This top view picture shows the 4x wide firing pin that will hit all of the rounds simotaneously and the trigger block that stops the pin. -by Oblivitus
8F3: High Power Mag Fed Shotgun: The magazine and barrel are the same as the mag fed shotgun, but the the trigger block is in front of the magazine. This will increase the power of the gun when firing its light weight rounds. -by Oblivitus
9F4: Bolt Action MG: A machine gun that has one very long firing pin and one much shorter one. The longer firing pin is cocked, and when the trigger is pressed, the shorter firing pin is repeatedly cocked and fired. -by Oblivitus
10F5: Adjustable Range Rifle: A rifle that has a long ranged slingshot sniper magazine at the back, and a shorter ranged block and pin mag fed gun at the front for its higher rate of fire. Ideally, there would be one trigger able to control each barrel individually with a switch. -by Oblivitus
11F6: Swiveling Shotgun: A burst fire gun whose trigger simotaneously releases the firing pin and the barrel so that it can spin to one side. The rotation creates horizontal spread. -by Oblivitus
12F7: MG 315: A 10 barreled machine gun. A very long trigger block is inserted into the barrels (shown as a double dotted line), it is attached at the bottom to a guide on the outside of the gun (the box around the dotted lines). The guide is pulled down by an elastic (to the left). There is a string wrapped half way around a wheel that is tied to another wheel near the trigger. When the trigger is pulled, the wheels spin, the string gives slack, the trigger block is pulled down by the elastics and each barrel fires from top to bottom. -by Oblivitus
13F8: Adjustable Range Pistol: A pistol that has a magazine and a folding barrel extension that transforms it into a slingshot. -by Oblivitus
14F9: Horizontal Mag Rifle: A rifle that uses the stock as a magazine. -by Oblivitus
15F10: Chain Fed Shotgun: A gun with a firing rod tip wide enough to strike three rounds at once. Two rotating wheels are positioned on either side of the gun on which a chain of chambers is spun around by elastics wound on one of the wheels. I suggest modifying the BR-18's design to fit this gun. -by Oblivitus
16F10: Chain Fed Shotgun: This back view shows how the rounds would move along the chain and how the three ready to be fired would line up with the barrel. -by Oblivitus
17F10: Chain Fed Shotgun: This top view shows the wide firing pin tip, the trigger block, and how the BR-18's design would be implemented in stopping the chain. -by Oblivitus
18F11: Shotgun Revolver: The drawing to the right represents a string of CS3 (Compact Shotgun 3) barrels set up on their sides with flexible rods on the inside of the circle and the outside of it holding them together. The drawing at the left shows how the flexible rods should be attached in a criss-crossing pattern to provide strength to the revolver. -by Oblivitus
19F12: Dual Barreled Revolver: A BR-18 with dual barrels, firing rods, and triggers. The triggers would either need to converge at a handle in the center, or use two handles (one for each trigger). -by Oblivitus
20F12: Dual Barreled Revolver: This drawing shows the location of the barrels more clearly. -by Oblivitus
21F13: Triple Mag Fed Gun: A gun that uses an extra wide ram tip to strike one rod fed from a magazine at a time. A slider comes in from one side to block all but one of the magazines. When the magazine that is currently in use empties, the slider is manually moved to allow the next magazine to push rounds into the barrel. The rods must be longer than the slider so that the ram will hit the rod but not the slider. -by Oblivitus
22F14: High Power Pump Action Revolver: A pump action that cocks a firing pin near the back of the gun with a string spun 180 degrees backwards then forwards again by two wheels. This design would be very efficient and therefore make the gun more powerful because it would eliminate bending that normally occurs in knex pump actions. -by Oblivitus
23F15: MG 210: This one works just like a baseball launcher. A full auto powered by motors located in the box labeled A. Box A will also house several gears that will be sequenced to increase speed. Large external gears or wheels will fire rounds as they drop between the gears. The magazine is gravity fed. The trigger will stop the rounds from falling out of the mag when released, and drop rounds into the firing mech while pulled. -by Oblivitus
24F15: MG 210: This drawing shows the rounds being fired by the counter spinning gears. -by Oblivitus
25F15: MG 210: This drawing shows how the trigger works by stopping rounds from falling into the firing mech. -by Oblivitus
26-30F16: Quad Barrel Shotgun: A shotgun that uses a primary and secondary pin to fire 4 rods. The primary pin strikes the secondary which is confined to a small space at the front of the gun and behind the quadruple barrel. The images are color coded for ease of part identification. -by Oblivitus
31F17: Hammer Gun 153: A gun that uses an elastic powered spinning mech to fire a rod. The rod is held in place by a mag pusher. In addition to the hammer, the spinning part has a short rod jutting from it that will strike the bullet when the trigger is pulled. This part also doubles as something for the trigger block to stop. The hammer should rotate 180 degrees (half a circle) when it is cocked. -by Oblivitus
32F18: Hammer Gun 536: Same as Hammer Gun 153, but uses a ratchet mech instead of a true block trigger. -by Oblivitus
33-34F19: SS10 Shotgun: Uses a slingshot mech to fire 10 green rods lined up on their sides. The rounds add up to about the same weight as an SRv2 bullet.
35F20: Rod Firing Mag Fed Slingshot: The elastic moves in order along the noted areas. It moves through 1-4 during cocking and 5-6 when fired. -by Oblivitus
36F21: Two Shot Mag Fed Shotgun: A mag fed gun that has barrel in front of the mag that fits two rods, but a barrel behind it that only fits one which the firing rod travels down. -by Oblivitus
37F22: Weight Powered MG163: After learning that all objects regardless of weight fall at the same rate, I realized that this gun will not fire very far (maybe 10-20 feet). 5 pounds of weights should be enough to make it fire. It uses a weight tied to a string that wraps around a wheel. As the weight drops, the wheel spins and repeatedly strikes the rounds loaded into the revolver at the front of the gun. The trigger stops the mech from spinning while it is released. -by Oblivitus
38F23: Slingshot Shotgun: A slingshot that fires several rods from a box. To load the gun, you cock it by pulling back the box with handles (one for each hand), then drop several rods into the box and pull the trigger to fire. The box has guides sticking out of it that go into slits in the gun. The bottom guide is stopped by the trigger when cocked. -by Oblivitus
39F24: Auto-Fire Pump Action: A pump action with a string attaching the pump to the trigger. When the pump is pushed all the way forward, the trigger is pulled and thus the gun fires itself. This allows for a higher rate of fire because it eliminates human reaction time and instead fires instantaneously.
40F25: MG 554: Could be a machine gun or a shotgun depending on how you build it and how fast that makes it fire (probably would be a shotgun). To cock it, a long, internal rectangular pin is pulled back. When the trigger is pulled, it rotates a gear, and a gear is rotated in the opposite direction by the first, which then rotates a tire (which has treads for friction) on a different layer, but is attached to the same rotation point as the second gear mentioned. The tire will rotate at the same rate of speed as the movement of the rectangular pin. This rotation will fire gray connectors from a magazine by pushing them out at high speeds. Gear ratios should be used to achieve maximum rotation speed while still maintaining sufficient torque (because the speed of rotation determines the range of the projectiles).
41F26: Semi-Auto Pich Fire Rifle: Uses the firing system from this gun, but instead of pulling a trigger to fire, the operator pushes the gun into their shoulder, which forces the stock forward and fires the gun. Could probably get 30+ feet with gray connectors. -by Oblivitus
42-46F27: 8-Barreled Semi-Auto: This one is better understood in images, so I won't get into describing it too much. Fires a yellow rod from eight block trigger barrels one after another (from left to right in the drawn example). Would get 50 feet of range easily. -by Oblivitus
43F28: Rotating Pin Gun: A gun that is powered by a long, large elastic that stretches around as much of the gun as possible. It is cocked by rotating a crank 360 degrees once which allows it fire a single shot. Could easily get 50 feet of range with a yellow rod. -by Oblivitus
44F29: Turret-Fed Shotgun: A 3 barreled shotgun, each barrel capable of 50 feet of range, that strikes 3 rounds out of a TR-18 turret simultaneously. One trigger pulls all the blocks at the same time during firing. One master pin pulls back the 3 firing pins. It is also important to note that the blocks should just barely touch the firing pins because there will be 3 times as much pressure for the trigger to overcome as a typical gun because there are 3 blocks. -by Oblivitus
45F30: Semi-Auto Pinch-Fire: Uses the concept of this gun to create automatic pinch firing which is then controlled by the semi-auto trigger system shown. -by Oblivitus

Step 7: Miscellaneous Weapon Designs

1G1: Full Auto Motor Rig: This motor setup can be used to get more torque out a full auto revolver or chain fed gun (which will allow much more powerful machine guns to be made). It works by using multiple motors in a line so that each will spin a gear that is lined up with the next gear, each motor added will increase the torque. -by Oblivitus
2G2: Revolver Speed Loader: This speed loader is built with chambers mirroring the revolver that it is made to load, but the ammo in the speed loader is locked in more lightly than the rounds in the guns revolver so that they can be transferred. This speed loader will replace using removable revolver chambers as a way of reloading. This picture shows the loader and the revolver before loading. -by Oblivitus
3G2: Revolver Speed Loader: This picture shows the loader and the revolver during loading. -by Oblivitus
4G2: Revolver Speed Loader: This picture shows the loader and the revolver after loading. -by Oblivitus
5G3: Magazine Storing Stock: A stock that stores a backup magazine. The red box represents the magazine and the dotted lines show where it is held.
6G4: Detachable Drum Mag: A drum mag (BR-18 revolver) that is slid onto a small gear (not necessarily a gear) to reload the gun. -by Oblivitus
7G5: Twisted Rod: This is a knex rod twisted by a power drill attached at one end, while the other end was held firmly in place (by a knex motor). This has not yet been tested (by firing it from a knex gun) for improvement in accuracy over regular rods. -by knexfreak95
8G6: Power Adjuster: A ratchet controlled by a hand crank used to tighten the firing elastics after the firing pin has been cocked to increase the guns power. There would also need to be a ratchet release. -by Oblivitus
9G7: Power Pack: A guns power supply that is stored in a magazine shaped device. It holds an elastic band, wound around a small spool, that is prevented from spinning by a blocking mechanism. When the power pack is inserted into the gun, the block is released and the guns block is simultaneously activated, putting the blocking feature at the control of the guns trigger. When the trigger is pulled, the power pack spins a rotating pin at high speeds to fire the gun. -by Oblivitus

Step 8: Miscellaneous Non Weapons

1H1: Cable Separator: This is seperator made for electronic cables. The first one was made by Mr. Cowboy, and this is my own idea for an improved version. The organizer opens to make inserting wires easier. The picture shows the separator with the hinged cover opened. -by Oblivitus
2H1: Cable Separator: The picture shows the separator with the cover closed. -by Oblivitus

Step 9: Real Life Weapon Designs

1I1: Adjustable Sights: This sight adjusts by moving a slider forward along a sloped base to increase the sights tilt for firing at targets at long range. -Oblivitus
2I2: Double Sided Magazine: Two magazines are attached together facing opposite directions for faster reloading. When one magazine runs out, it is flipped over to reload. -Oblivitus

Step 10: Concepts in Progress

These are incomplete ideas.

1J1: MG 4113: A revolver machine gun that is spun by elastics. Block triggers are pulled on the inside as it spins. -by Oblivitus
2J1: MG 4113: This picture shows the staggered pattern of the barrels on the revolver. -by Oblivitus
3J2: Bouncing Betty Grenade -by Oblivitus
4J2: Bouncing Betty Grenade -by Oblivitus
5J2: Bouncing Betty Grenade: This picture shows how it works (part 1). -by Oblivitus
6J2: Bouncing Betty Grenade: This picture shows how it works (part 2). -by Oblivitus
7J3: Weight Powered MG: A machine gun with a reciprocating mech powered by the dropping of weights attached to spools of string. -by Oblivitus
8J3: Weight Powered MG -by Oblivitus
9J3: Weight Powered MG -by Oblivitus
10J3: Weight Powered MG -by Oblivitus
11J3: Weight Powered MG -by Oblivitus
12J3: Weight Powered MG -by Oblivitus
13J4: Revolver Ramp MG: A machine gun revolver that spins quickly, firing pins are pushed forward as they rotate around a ramp. -by Oblivitus
14J5: 4 Barreled Gun: The following are pictures of a quadruple barrel design. -by Oblivitus
15J5: 4 Barreled Gun -by Oblivitus
16J5: 4 Barreled Gun -by Oblivitus