Introduction: MAR-4

Picture of MAR-4

This is my MAR-4 (Masterdude Assault Rifle version 4). Upon request of fellow members of the K'nexing community here, I have made it using a new firing mechanism (firing pin/ramrod type). It fires my standard ammo, however if you are doing single shot then it will shoot blue rods, and others if you load down the barrel.

-Adjustable sight
-Trigger guard
-Cheek rest
-Removable magazine
-Vertical grip
-Good power
-Can be breech loaded

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Image 1: Gun with optional gear.
Image 2: Gun without optional gear.

Step 1: Main Body: Components

Picture of Main Body: Components

Make the following as shown in the images. They will be assigned a letter for further reference:

Step 2: Main Body: Construction A

Picture of Main Body: Construction A

Follow the steps:

Image 1: Add blue rods to Part A.
Image 2: Add Parts B and C, gray connectors, and white rods.
Image 3: Add Parts C, D, E, F, G, H, I, J, and N, and gray connectors.
Image 4: Add Parts C and K, and gray connectors.
Image 5: Add Part L.
Image 6: Add Part M.
Image 7: On other side, add metallic blue clip and gray connectors.

Step 3: Main Body: Construction B

Picture of Main Body: Construction B

Follow the images:

Images 1-2: Make these.
Image 3: Put them together as shown.
Image 4: Place it as shown.
Image 5: Make this (Ramrod/Firing Pin).
Images 6-12: Make this as shown in the images (images are step by step) (Charging Handle).
Image 13: Place the Ramrod/Firing Pin as shown.
Image 14: Flip red connectors up as shown so they snap into place with the white rod.
Image 15: Place the Charging Handle as shown.
Image 16: Connect the two together as in the image.

Step 4: Magazine

Picture of Magazine

Follow the images:

Images 1-2: Make 2 of each.
Images 3-4: Make 1 of each.
Image 5: Add white rods.
Image 6: Add the other parts as shown.
Image 7: Cover with the last part.

Step 5: Sight

Picture of Sight

Follow the images:

Images 1-3: Make 1 of each.
Image 4: Make 3.
Image 5: Add blue rods as shown.
Image 6: Add the 4th part, silver spacer, and light gray connector.
Image 7: Add the 1st and 4th parts and a tan clip.
Image 8: Add the 4th part, silver spacer, and light gray connector.
Image 9: Cover with the 3rd part.
Image 10: On other side, add a gray connector.
Image 11: Add a tan clip as shown.
Image 12: And add a small gear.

Step 6: Front Grip and Cheek Rest

Picture of Front Grip and Cheek Rest

Front Grip: First image. Further instructions should not be necessary.

Cheek Rest:
Image 2: Make 2.
Image 3: Make 4.
Image 4: Put them all together using blue rods as shown.

Step 7: RubberBand Placement

Picture of RubberBand Placement

Follow the images:

Image 1: Pull the yellow rod to the right.
Image 2: Put rubberband around the blue spacers as shown.
Image 3: Pull rubberband under the ends of the blue rod as shown and hook on the blue spacers on the other side.
Image 4: Push the yellow rod back into the center.

Step 8: Operation

Picture of Operation

Placing the rubberband as shown in the trigger area (image 3), load the magazine (image 2) with ammo (image 1). Take the magazine and insert it properly into the magazine feed. To cock it pull the charging handle back as shown in images 3 and 4. To load using the side breech, lift the breech up to open up the breech, and then insert the ammo. Then close it by pulling the breech down (images5-7). Then you shoot by pulling the trigger to fire, and pull the charging handle to reload. To aim you can use the sight (image 8). You can adjust it for better accuracy. Proper attachment of optional gear is shown in image 9.

Warning- This may cause harm or injury if misused. Do not point it at people. I am not responsible for damage, injury, or death caused by this instructable. Even with safety engaged it can fire. Always treated it as armed.


~KGB~ (author)2011-05-01


Masterdude (author)~KGB~2011-05-01

On the other side there is a flap/breech which can be used to single load the gun. You can see it in the 8th Step.

~KGB~ (author)Masterdude2011-05-01

pretty cool feature =D

beanieostrich (author)2011-04-27

Looks epic man 5*

Masterdude (author)beanieostrich2011-04-28


beanieostrich (author)Masterdude2011-04-28

No problem XD I like your latest bullpup SMG =)

Masterdude (author)beanieostrich2011-04-29

Thanks. SMGs are nice, but bullpup makes them even better. " =) "

beanieostrich (author)Masterdude2011-04-29

I like bullpups, but my fav is the F2000 =D I like using smiles XD You should see some of my things.

jmm72 (author)beanieostrich2011-04-27

Good job. 4.5*

beanieostrich (author)jmm722011-04-28

Why did you reply to that?

jmm72 (author)beanieostrich2011-04-28

i didnt mean to

beanieostrich (author)jmm722011-04-28

Its alright, thats happened to me before =D

Masterdude (author)jmm722011-04-28


Fred the evil puppet (author)2011-04-29

now this looks AWESOME!!!!!


The Nomlack (author)2011-04-27

This is really great! 5*

Masterdude (author)The Nomlack2011-04-28


The Nomlack (author)Masterdude2011-04-28

Np. i really like the side loading mech!

Masterdude (author)The Nomlack2011-04-29

Thanks. I wanted to make something new and more-less practical. Now you can load without removing the mag.

spazgadget (author)2011-09-13

help! my gun wont cock! it just slips past the trigger! help please!

Masterdude (author)spazgadget2011-09-23

I don't know what's wrong, but it may be that you don't pull the charging handle thing back far enough, or the trigger may not be pushed enough by the rubberband (then get a stronger rubberband on it). I hope that helps, if not then PM for further assistance.

skyfaller (author)2011-07-23

Can anybody make a piece count? i don't wanna build it to the end and not have enough for something.

FuNbOy77 (author)2011-06-27

ok thanx

Masterdude (author)FuNbOy772011-06-28

You're welcomed.

FuNbOy77 (author)2011-06-25

Do u only need 1 Y connector for the whole gun?

Masterdude (author)FuNbOy772011-06-27

Unfortunately no. You need 6 I think for the removable mag, however if you can't manage 6, you could mod it so the mag is not removable and you wouldn't need any, I think.

tytiger33 (author)2011-05-18

I built it and loved it except for one thing range. I love that you are making ramrod guns but next time make it so the ram rod isn't attached to a charging handle and then the range will be much better. And could you maybe build a good pump action gun? If you do that would be great!

Masterdude (author)tytiger332011-05-18

I know the range isn't as good as in my previous guns. Currently I have made some new ramrod guns and will post them later. They however are more compact and are side arms.

tytiger33 (author)Masterdude2011-05-19

OK well then keep on working on this one and try to make a better second version.

Torpe (author)2011-05-12

On the MBSMG, do you have to pull back the bands/pin for every shot?

Masterdude (author)Torpe2011-05-12

No, only when loading. Also could you comment/ask about an Instructable on that Instructables page?

laserbeam (author)2011-04-28

will you be making more guns like your othher ones (mars mbar, msmg etc)

Masterdude (author)laserbeam2011-04-28

Of course. However they will probably only be coming back in a few months. I have now created a mechanism which works well enough for me and the next few guns will be based off of things that I've developed for this gun.

When you dot, make a pistol!
Call it the MSAP!

I probably will. However I may call it the MSAU-3 like ones before it. What general characteristics do you think I should add to make it a MSAP, not a MSAU?

laserbeam (author)Masterdude2011-04-30

a very short barel (7 cm)

Masterdude (author)laserbeam2011-04-30

Anything else?

For realism, have a slanted handle as the mag, and please DON'T use the same mechanism that the MSAU uses. (not the pseudo, i mean bullpup)

I'm working on a slanted handle (will probably not have a removable mag). As for the trigger I will try making a ramrod/firing pin mech first, then maybe a semi-auto.

laserbeam (author)Masterdude2011-05-01

a removibale mag inside the handle and no foregrip

Masterdude (author)laserbeam2011-05-01

On the other side there is a flap/breech which can be used to single load the gun. You can see it in the 8th Step.

DJ Radio (author)2011-04-30

On the plus side you're starting to put variety in your designs, but on the minus side this isn't anything new or special.

Masterdude (author)DJ Radio2011-04-30

The side breech loading is new and the mech. What would you like to see me make into my next guns?

DJ Radio (author)Masterdude2011-04-30

What side breech loading?

Masterdude (author)DJ Radio2011-05-01

On the other side there is a flap/breech which can be used to single load the gun. You can see it in the 8th Step.

laserbeam (author)2011-04-28

i mean the semi auto mech

About This Instructable




Bio: I make K'nex guns, specializing in semi-automatic, RBG-Slingshot hybrid systems which i use in most of my guns. Note: I am not responsible in ... More »
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