Introduction: MSAU

About: 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 any way for any damage, injury, or death caused by my Instructab...

This is my second Uzi but unlike the earlier one this one is larger and true semi-automatic with a removable magazine but it still uses the same ammo. Really it should be called a MAC 10 but I prefer Uzi. This is an improved version of my earlier MSAU which has the problems rectified.

-Removable magazine
-Doesn't use too many pieces
-Can have optional front grip and stock
-Rather easy to use

-Handle might be uncomfortable for some people
-Can be hard to load at first (But becomes easier with some practice)

More Instructables by me.

Note concerning problems in the earlier version of the MSAU: This is an improved version of my earlier MSAU! This version has the problems fixed! The trigger system is stronger and the magazine holds better to the gun. It still may disconnect from the gun by accident but it has been reinforced and will withstand most conditions except the most violent and strong movements during which the magazine/handle may disconnect from the gun.

Noteconcerning images: Image one shows the MSAU with optional additions. Image two shows the basic version. Image 3 shows version compatible with additions but without them.

Step 1: Main Body: Making the Components

Make the following. Each will be assigned a letter for identification:

Image 1: Make 1. (Part A)
Image 2: Make 1. (Part B)*
Image 3: Make 2. (Part C)
Image 4: Make 1. (Part D)
Image 5: Make 1. (Part E)
Image 6: Make 1. (Part F)
Image 7: Make 1. (Part G)
Image 8: Make 1. (Part H)*
Image 9: Make 2. (Part I)

*-The indicated yellow connector can be replaced with a red connector if you don't plan on adding optional additions.

Step 2: Main Body: Construction

Follow the images:

Image 1: Add white and blue rods to part A where indicated.
Image 2: Attach part B and add white and blue rods.
Image 3: Attach part C, and tan clip, white rod, orange connector, and 2 blue spacers.
Image 4: Add parts D, E, F, G, and add blue spacers and orange connector.
Image 5: Add part C, blue spacers, and an orange connector.
Image 6: Add part H.
Image 7: Add part I, tan clip, and a white rod.
Image 8: Add part I.
Image 9: Add metallic blue clip.

Step 3: Barrel (Part A): Making the Components

Make the following:

Images 1-2: Make 5 of each.
Image 3: Make 6.

Step 4: Barrel (Part A): Construction

Follow the images:

Image 1: Add yellow rods.
Image 2: Add the earlier made parts as shown.
Image 3: Add the earlier made parts but with their places switched.
Image 4: Continue until you end up with this.

Step 5: Barrel (Part B): Making the Components

Make the following:

Image 1: Make 2.
Image 2: Make 1 (make 3 if you don't want attachments).
Image 3: Make 2 (make 0 if you don't want attachments).
Image 4: Make 1.

Step 6: Barrel (Part B): Construction

Follow the images:

Image 1: Add blue rods.
Image 2: Add the earlier made part as shown.
Image 3: Add the earlier made part as shown.
Image 4: Add the earlier made part as shown.
Image 5: Add the earlier made part as shown.
Image 6: Place the earlier made part as shown.
Image 7: Add a metallic blue clip.

Note: If you don't want optional attachments replace the parts added in images 2 and 4 with the other parts you've made.

Step 7: Magazine/Handle: Making the Components

Make the following:

Image 1: Make 2.
Image 2: Make 1.
Image 3: Make 2.
Image 4: Make 1.

Step 8: Magazine/Handle: Construction

Follow the images:

Image 1: Add white rods.
Image 2: Place the earlier made parts as shown.
Image 3: Cover with the earlier made part.
Image 4: Finished magazine with ammo and pin in place.

Step 9: Optional Additions

Vertical Front Grip: You can make a vertical front grip as shown in the images. You should be able to make it from the first two images without the need of written instructions.

Stock: You can also make a stock.
Image 3: Make 2 of these.
Image 4: Add blue rods and orange connectors.
Image 5: Add the other part onto the blue rods and orange connectors.

Step 10: Putting Everything Together

Image 1: Connecting (Barrel Part A) to Barrel (Part B).
Image 2: Connecting Barrel (Part B) to Main Body.
Image 3: Connecting Magazine to Main Body.
Image 4: Connecting Front Grip to Barrel (Part A).
Image 5: Connecting Stock to Main Body.

Step 11: Loading and Firing

This gun loads and fires like most of my guns like my MAR, MAR-2, and MBAR. To load you first remove the magazine and put the pin in place, and then you insert the ammo which is shown in the image below. Then you insert the magazine into the appropriate place until it firmly holds in place. They you push the white rods over the ammo feed out to the side and you take the rubber-bands and hook them on the tip of the barrel and then on the spoke in the back of the gun. Then you push the white rods back into place and pull the pin out of the magazine. To shoot you pull the trigger.

Image 1: Ammo.
Image 2: Loaded. View of barrel end.
Image 3: Loaded. View of ammo feed.
Image 4: Loaded. View of trigger system.

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.



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    32 Discussions

    It is the first part, which is used in image 1 of the Main Body: Construction step, and to which the rods are attached to.

    Couple of things:

    This is not a true semi-automatic; it is a pseudo semi-automatic. You use a preloaded method of firing. See ooda's thread on true/pseudo semi-automatics.

    Your gun isn't an M10. It's an M11 (longer reciever/ semi only operation).

    Other than that, the fore-end of your gun is pretty nice.
    17 replies

    In my mind, a semi auto gun is one where, whenever you pull the trigger, a bullet comes out. (provided there is a bullet and a power source)

    I do question why exactly this isn't true semi-automatic. Rubber bands are just an acting force on the projectile just as exploding gun powder is on real bullets, right? This method is more like a real fire arm than other semi autos. I'm not saying it's any better though.

    This method is more like attaching a bunch of muskets together and calling it a semi-auto. See ooda's thread.

    No it's not. That's the Gatling guns last I heard. I see no multiple barrels or firing devices. It's as if there's gun powder stored else where and just the bullets being loaded but still it's one gun firing multiple rounds each with its own source of power and the ability to fire them in succession by pulling the trigger. Why exactly would this not be considered true semi auto? It's not traditional but it's still applying the same concept.

    Operative word being like. I did not say it was attaching multiple single-shots, but that it was like. You don't have to cock a  1911 eight times to fire eight shots, ergo you should not have to load eight bands and then load eight bullets in order to fire eight shots.

    Ah, but you see, do you not need to mix up and load each bit of powder for cartridges just as much as you must prepare a rubber band on the gun? I understand where you're coming from but a real fire arm's firing mechanism doesn't actually project the bullet. It simply sets off the powder. Same goes for RBGs. The mechanism releases a rubber band which acts as the powder in this case. They both follow the same idea just using different methods so essentially that makes the RBG just as much of a semi auto as real semi auto firearm.

    I realize that. It doesn't mean that they are completely different other than that. So would you call a firearm that had a separate loading container of powder and a separate magazine for just the bullets that still fired with every press of the trigger pull not a true semi automatic? Seeing how K'nex cannot fully replicate real fire arms, the least it needs to do is simply fire with every pull of the trigger. An RBG does that. Every other element to a real fire arm is similar. Each bullet has its own potential energy stored and is loaded into its "chamber" automatically. They can be fired with a pull of the trigger. There is no other preparation other than setting the bullet up itself whether done by you or another.

    RBG's are semi-auto. These pseudo-semis are not true semi-autos. What you have here is tantamount to having a pump action rifle.

    Let's say it's one of those overpriced Remington 7615s. You have to pump once per shot, that's what makes it a pump-action rifle. Now, say you could pump it ten times and then fire ten rounds without pumping it again. Is it still a pump action, or does it suddenly become a semi-auto? 

    You still pumped the gun once for each shot you fired. What does it matter if you pumped it once after each shot or ten times before you fired ten rounds? It is still a pump-action. Same goes with these pseudo-semis. You are just pumping it eight times in order to fire it eight times. What does it matter that you pumped it eight times before you fired? You still pumped it once per shot.

    You seem to not be understanding the whole rubber band is similar to bullet thing. Rubber bands are the acting force on the K'nex pieces right? Powder is the acting force on bullets right? The main difference is that you can buy prepared bullets while you have to prepare rubber bands on the gun yourself. You are not "cocking" a weapon by loading RBs. You are "filling it with powder" in a sense. I repeat, it's not the firing mechanism that actually shoots the bullet. It just sets off the acting force, whatever it may be, that shoots the bullet. Powder for most real fire arms and rubber bands for these types of K'nex guns.

    I ask you another question. Please don't shift it with one of your own questions. What would you call a gas airsoft gun? They're in a similar boat. You usually have a separate storage+loading area for the BBs and then another place for gas storage. Yes, they're not together but when you load both you can still fire semi automatically with a pull of the trigger. Most people would call that a true semi auto.

    GBB's are true semi-automatics. Difference is, you put in one cartridge for thirty shots. For this, you have to put one band for one shot.
    Editing: As in, you could put one band and four rounds, but only be able to shoot once. Whereas you could put one CO2 cartridge and four shots and still fire all four shots.

    But cartridges aren't that way. Each bullet has to be separately prepared with their own bit of gun powder. I understand that you don't have to do this yourself but it's still a necessary process to make the bullets fire. If you loaded only one with gun powder then all the same it would only fire one bullet.

    Again, going back to the 'Bullets are self- contained' argument. But clearly you won't agree with me, and I won't agree with your illogical statements. As far as I'm concerned, you only have to load a gun once per cartridge for it to be semi-automatic.

    Lol calling me illogical? So your argument is that the bullets determine the firing mode of the weapon? That's illogical. Say you had some sort of modified gun so that there was container for bullets and a container for powder. They were completely separate and you had to fill each one separately but they still loaded the gun together so that it would fire with a pull of the trigger. It would no longer be considered true semi auto because the bullets aren't self contained?

    Pretty much. A real semi-auto works by pulling back a hammer, creating potential energy, then letting it slam forward into the primer. The primer then creates pressure and propels the bullets.

    In this, you are pulling back a bunch of bands. When you pull the trigger, you are not creating potential energy, you are releasing energy that is already built up. You don't create the energy that propels the bullet when you pull the trigger.