Step 10: Trigger rod

I used a a 1/8 thick by 3/4 inch wide aluminum bar. Iron or steel bar will work too. So will a round rod of some sort. Do what ever is best for you.

Picture #1: Measure from the center of the XM PB4 grenade valve (the silver circle) to the top of the control box. Transfer that measurement to one end of the trigger rod. Bend the trigger rod 90 degrees or more. shape and bend the tip so that sliding the trigger rod forward will depress the grenade valve.

Picture #2: Cut the long end of the trigger rod/bar to match the lenght of the control box. Depending on the material used for the trigger bar/rod find a away to secure it to the control box. I used a flat bar so I used "L" brackets to hold the bar captive.

Picture #3: Attach something (screw, rod, d-ring, etc) to the bar so that you can grasp it and push the bar forward which will depress the back of the XM PB4 40 mm grenade shell.

Make sure that when you Extend the launcher the something above (screw, rod, d-ring, etc) has clearance to slide backwards unhindered. When the launcher is collapsed, you want something to hinder the something above from moving forward as a "safety".

Picture #4: *Optional*
Install a spring to prevent the trigger from accidentally pressing the valve.

Pictures #5-10 are to help visualize the whole mechanism.
hey i know a way to make one that fires any 40mm grenade. not quite as simple as yours, but very realistic. i had bought an m72 body, de militarized for training. i put a 2 inch barrel in it. i drop the grenade in the back, slide in a actuator from an automotive power door lock, and close the back. i was able to get the body for $50, the actuator for $8, and the small 7.2v lipo battery that powers it for $15. oh, and the fire button for $2.
Is the Fiberglass just to make the outer tube, or does it also help reinforce the PVC, I want to make one of these, but if I don't require all of the fiberglass and additional parts and I can make a more basic version that would be great, but I was concerned with having pressure in the PVC tube.
hey so far ive made one for my friend and am making one for myself i also have a 3D printer so i designed a trigger for it and also am going to design a part for that goes on the aluminum rod to depress the button is here is the link to the trigger http://www.thingiverse.com/thing:104019?save=success
This is so cool. My best buddy works for a <a href="http://www.ontarioinjured.com" rel="nofollow">law firm in Ottawa</a> and his son is really into Call of Duty and I think I will have to do something like this for his birthday in the future.
Building one as we speak, this is like 3 years in the making. I'll post a video once I'm done. Basically building to the schematics of this instructables, with a few minor differences. I'm using very similar parts, with the exception of a few, namely the grenade, and the shielded coupler. I realize that what you have posted are the exact specifications for a product that will 100% work, though, being unable to acquire such items was difficult, as I am in Canada. I have a fair understanding of all the parts and realize that essentially you're just looking for a rear-load green gas grenade, and a shielded coupler which reduces from 2inches to 1.5 inches. If you are looking to make an airsoft grenade launcher: <br>1. For a reasonable price <br>2. That doesn't look like plumbing parts <br>3. That is easily made within a week <br>4. That will rival any $1000 launcher on the market <br>5. Can be used on virtually any airsoft field <br>6. Will not be turned down for use, as all potato guns are (even though they may be the most high-tech thing out there) <br>And probably the most important part of this instructable, as all instructables by MrTinkerer: <br>7. Sticks to the best principal - KISS: Keep It Simple Stupid. <br>I have spent countless hours on the internet looking for a product that even rivals this, that is home made, for under $120.. Needless to say, there isn't anything close. Stick with this instructable, and be smart about it. If you read the directions one by one, carefully, as well as the comments, you will find literally EVERY answer you may have a question to. Even if you're a novice, this makes sense. Basically you could take the coupler, the grenade, and a piece of ABS or PVC and depress the trigger on the grenade with your finger, and you would have the most basic form of this weapon. The fiberglass as well as the externals are not required to make this weapon work. It just makes it much more functional. <br>Thank you MrTinkerer, you are a god among men. No joke. <br>I am going to school to be a gunsmith and machinist technician so I can start building my own guns, and eventually open the most bomb airsoft facility ever. I'm talking downed heli's, airplanes, indoor CQB, and outdoor scenario play. I have ideas to host a apocalypse day/week/month every year around halloween, where players will set out, and zombie-costumed staff by the 100's will attack unsuspecting players through ambush and surprise. Think COD and Battlefield maps, only real life. That being said, if and when I get my business up and running, I would love to work along side for your expertise and innovative standards in everything you do. Very impressed to say the least.
Wow! so much flattery in the comment above. you are too kind. thanks. but, humbly, i am just a guy who likes to make stuff, nothing more.... <br>I am very much looking forward to seeing your launcher. Please send me a youtube link when you are done.
interesting. This has been a major topic of discussion for <a href="http://www.utahcustodydivorceattorneys.com" rel="nofollow">family law utah</a> recently.
I live in Canada and I cant see to find part no. 3001-215. Part no. 3000-215 is avalible but Im not going to purchase the grenade unless the grenade fits in that coupler. On the fernco website it says that part no. 3001-215 is 2&quot; CI, PL. or ST. to 1-1/2&quot; Copper or 1-1/4&quot; PL while part no. 3000-215 is 2&quot; CI, PL or ST to 1-1/2&quot; CI, PL, or ST. I assume that the grenade will fit in part no. 3000-215 becuase the 1.5&quot; end is 38.099999999999994mm's and should fit the 40mm grenade snugly. Thoughts?
Yes, whats important is that one end has an opening 1.5&quot; or as close to 40mm as possible and the other end has an opening that is the corect size as the pipe you are using.
OK Thanks.
How much did this cost in total?
Biggest cost in the grenade. Should cost 100-120 total.<br>
OK. Thanks!
Ive finished my law, and it turned out great. one problem i have is that the grenade (Mad Bull XM-PB4 Dummy Round BB Grenade Shell) will jam. after firing it once ore twice, the valve that is pleased does not come back out all the way. this makes it unable to be filled. i had my friend bring his mad-bull shell over and it did the same thing. did you have this problem? if so, how did you fix it?
on airsoft grenades you need to push the button in until you hear a click with a pen or something similar and release this resets the grenade.
Yeah. My mad bull does the same thing. I carry a nail for resetting the valve. Just press the valve all the way to the bottom. It will click when it is reset.
Is there any substitute to fiber glass???
carbon fiber
If we wanted to go for carbon fiber, what would you recommend? Multiple layers like you did with the fiber glass? Single layer with a thicker sheet? I understand that using the fiber will probably make the build more expensive no matter what, but I'm just trying to minimize cost while making the outer tube (hopefully) more durable.
Fiberglass will be significantly less expensive even if you did 5-6 layers. Fiberglass is very strong even with 2 layers.
Just out of curiosity, would the launcher be able to fire loaded 40mm grenades instead of nerf balls? Like, if I loaded the grenade and left the nerf ball out, would it damage the weapon?
not sure
This is still me. I've also noticed that it uses a different type of grenade. So, if I loaded a bb-type 40mm grenade, instead of the multipurpose grenade and Nerf rocket, would it damage the fiberglass tube?
Hey where do you find nerf balls I already checked walmart they didn't have it and I don't know if toys r us has it. I know that Toys r us and everything discontinued their sale of nerf vortexes for some reason so where could you find those?
how many times do u wrap the wax paper and mylar around the pvc
3-5 layers. It depends on how thick the material is. We want a tight fit but we also want the pvc tube to be able to slide. the fiberglass shrinks a little as it cures.
where did you get the gas can or online? cuz i buy things online more then in the stores <br>
local store. i dont like paying for shipping.
Which air grenade is better, or is all of them are the same and have the valve on the back? <br>
what is yours or anyones average range with the S-Thunder grenade? Im building several LAWS for friends and some of my contacts throught the airsoft manufacturers have stated that the XMPB4 has been discontinued through Mad Bull... Im only getting about 20yds with the S-Thunder grenades as the power source, yet we played 2 weeks ago with my LAW and I got a 175yd launch with the XMPB4 :)
I used an ignition system of a BBQ sparker and static-guard. It seams to ga farther that the green gas and it dosent take time to warm up. Just out of curiosity, why did you use green gas?
I dont want an ignition launcher. This is a non-fire, non-ignition instructable to make it universally field legal. As far as I know most legal paintball and airsoft fields will not allow potato canons in their games. That is why I am using green gas in a non-ignition way. Just playing safe.
Cool! If only nerf wasn't so restrictive of power, then kids will be shooting each other with stuff like this (although injury can occur more, hmm...).
I'm confused does it shoot bbs or a NERF ball?
Did you read Step 1?
is the grenade reusable? i don't wanna spend another $80 on only 1 grenade. And also, are there cheaper ones? I plan on making this instuctable. Its totally awesome :D
Yes and yes. Google &quot;S-Thunder grenade&quot;. I think 50-60 bucks.
Hey could you use 40mm PVC or CPVC instead of an expensive airsoft gernade?
I don't know what a 40mm PVC, so I don't know. Besides, my design is field tested and works great the way it is.
sorry if im being annoying but how much would it cost in total and when u fire, does the grenade thing launch too?
ok so I want to make your launcher but i want to use the s- thunder multipurpose grenade ,but i want to be able to shoot bbs and nerf rockets..any suggestions on making the grenade able to be taken out during battle so i can reload
what is the greenish tape stuff?and where can i find it?
Green self adhesive felt.
will the s-thunder fit as well as the mad bull in the coupler?
most likely yes. Remember the s thunder and the mad bull is a replica of a 40mm grenade shell. With that said, they will mostl likely have the same diameter.
What is the locking mechanism for is it to hold the metal bar in place?
no. It is to lock the tube in the extended position.
i made one of these and its so awesome!

About This Instructable


160 favorites


Bio: I like to tinker and create things. When I have time, i make stuff. The stuff could be as simple as my patent pending spoon-on-a-stick ... More »
More by MrTinkerer: Automated Pneumatic Button Pusher Make a 3D Printer using a CNC router - Deltabot How to take part in Red Bull Flugtag - Portland 2015
Add instructable to: