Bullpup marker

[kingmt]

I've always wanted a bullpup style marker. I love the look of the P90 and the fact that it is so compact. I actually started tinkering with a couple design ideas about 8 years ago but I never made much progress. The DFender is close to what I want but not quite so I decided to try my hand at designing my own bullpup again. This time I have design experience with Fusion 360 to help me in my design and a resin and fdm 3D printers to make the parts I need for my design.

For the base of the build I started with a Spyder MR3 body. I picked the MR3 since it was right feed and had eyes. Since the trigger is going to be far away from where it normally is a sear tripper design was out of the question. Since I was starting with a Spyder body my first idea was to use an Intimidator ram tube. I started with a Gen 2 tube but then I saw the Gen 4 design with the new poppet design and thought I liked that idea move. Turns out finding the parts for a Gen 4 Intimidator ram tube is fairly difficult, I couldn't find all that parts. I did find one site that had a complete tube but they wanted $95. Then I saw the new Dye Lazarus valve and decided I would make the ram in the style of a Impule/Ego.

I modeled the body and discovered that it was a really good thing I decided to drop the Intimidator ram tube. Turns out the bolt action distance on the MR3 is 30mm. It also meant that the ram design would end up looking like a combination of an Intimidator and Impulse/Ego. I really wanted to shorten the MR3 body so that I could put a hopper feed gate at the back of the body instead of to the side. So time for a new idea. Then it occurred to me that if I am making a ram to open the valve, why not make a second ram for the bolt like the original Shocker? So I started down that path and I started making some good progress. Since I was making a ram for the bolt a normal stacked tube bolt wouldn't work so I modeled the bolt after the Shocker. The distance from the valve exhaust to the barrel was longer so I had to take that into account.

Since I was going to be using 2 pneumatic rams for the valve and bolt that means I need 2 solenoids and a LPR. First easy answer for the LPR was to go back to the Intimidator and use the front block. But this time I had a different problem. The spine of the marker. Since the trigger frame was going to be moved forward it would not mount directly to the body. I was going to start with some aluminum stock 3/4 in wide by 1/2 thick. To use the Intimidator LPR I would need a hole in it big enough for an ASA. I picked aluminum since I new I was going to have to drill holes in it. I stumbled across some aluminum T track and realized this might be a better answer than a solid aluminum bar. The sides of the T track are what gives it strength so I could put holes wherever I wanted and not worry about the strength as long as I left the sides alone. I ended up changing my mind to an autococker LPR on a custom front block. Open question, can a 3D printed front block hold 200-250 psi? If not I will have to go back to the Intimidator front block.

With those questions out of the way I turned my attention to the hopper. I needed something that could push paint up a channel. I disassembled my Prophecy and looked at how everything was put together. I noticed the eyes in the feedneck and thought it would be a good idea for my hopper design to put eyes at the top of the channel. If I were to salvage the Phrophecy I would have to desolder the eyes on the board and use an eye harness. So I started looking at other hoppers to if there was something better and I found it. A Halo B had an eye harness. I took the Halo B raceway and redesigned it from a downward channel to an upward channel. Since I was redesigning the raceway anyway I decided to make it smaller to have a narrower profile. I ended up reducing the raceway diameter from 90mm to 76mm. Since the hopper is going to be alongside your forearm when you are holding the marker narrower is a good thing.

Then there came the question of tank mount. I decided to cheat and run the tank off gun using a remote. But I may revisit this after looking at the new First Strike Half Pint tanks. I have to find out what the threads to see if I can use my Max Flo regulator. That way I don't need a regulator between the tank and the gun.



Final parts list
Spyder MR3
Dye Lazarus valve
autococker LPR
2x Dangerous Power Fusion Elite solenoid
Morlock control board
barrel TBD
Halo B

Custom designed and printed parts
valve ram
bolt ram
bolt
feed elbow
hopper raceway
hopper shell
LPR front block
shroud
foregrip styled off of the MR3 trigger frame

And here is my design. I am still finalizing some of the details but I think I will be starting to print prototypes in the next few days.

[kingmt]

Here ore some pics of the internals

The 2 rams are going to be printed as 1 piece so I can route the air for the bolt ram around the valve ram. The valve ram has an action distance of 3 mm. I don't want to slam into the valve to open it. I did find some softer springs for the valve so I can see how low pressure I need for the ram to open the valve. The green rectangle under the rams is one of the DP solenoids. This first design has them sitting side by side under the rams to make it easy to route the air.

I forgot to put batteries in the loader drawing, but they will go in the middle compartment next to the raceway. I did make an access door to be able to change the batteries without removing the shelf. The cross section colored 1 part wrong. Next to the board is a green cylinder going through the backplate. That will actually be a acrylic rod. That is the spot the LED is mounted on the board.

In the loader/feed elbow picture you will notice a wire connector on top of the loader. The white band on the elbow is actually an eye cover. So the loader eye will be detecting paint just before it falls into the breach, meaning the loader will attempt to feed paint until there is a round waiting to be chambered

[markdem]

I personally would have used a Smat Parts Ion as the core but its good to see youre turning nasty spyders into something cool! Keep us updated

Out of curiosity, why are you designing this gun? What didnt you like about the dfender?

[Toestr]

It would have been just as easier to keep this a blowback. Since it's electronic you can have the board wherever you want, the switch wherever the grip ends up and just run wires back to the solenoid to trip the sear.

I know this is MCB and Rube Goldberg is our hero but just in case there was no other reason for the pneumatics other than your concern over a linkage to the sear.

[Morgenstern]

https://www.mcarterbrown.com/forum/paintball-news-aa/the-armory/vm-empire/320-the-official-vm-empire-picture-thread

Please make a big fat full length barrel shroud with gills in it like Chaos' VM in this thread! :-)

[COB]

I love the creativity here. Yes, you could have simply bought the BT Defender or the Tippman Raider. But each has its own drawbacks. I see that your design addresses some of the ergonomics issues with the hopper location and its impact on a line of sight down the barrel. I can not wait to see it finished.

[kingmt]

I started with a Spyder MR1 originally because of the right feed. At the time I didn't realize how the Ions were put together and that I could just turn the breach upside down. But truth to be told even if I had realized it when I originally started with I still would have avoided the Ion. This is a good summary: https://www.reddit.com/r/paintball/c...rse_a_gog_gun/ I will say I do not 100% refuse the use Smart Part/GOG. I love my Max Flo regulators. So I made a compromise with myself. I will avoid all Smart Parts/GOG products unless they are significantly better than the competition or simply not otherwise available. The Max Flo is a prime example. If another tank company released an adjustable reg that went down to 200psi I would use it. Ninja is close, but not quite.

Now I did pick up some Dangerous Power G3 parts for a possible follow up project... The GOG Enemy doesn't have a metal power tube. The power tube is plastic. So maybe if I printed the resin 5mm thick it might be able to hold the pressure... That one I won't attempt until I figure out a safe way of testing it.

As far as leaving it as a blowback sear tripper. I don't like blowback guns. Maybe its an efficiency thing, but they seem so wasteful with the air. That's why my initial approach was to be based off of the Intimidator.

One thing I forgot to mention is that I will be shaving 1 3/8 inch off the back of the Spyder body by going to separate valve and bolt rams. I think I left the abandoned ram idea in the design and didn't delete it. If I did I will post a picture showing why I abandoned that version.

As far as not getting the DFender. I was "this" close to getting one on multiple occasions. It comes really close to what I want. The thing is, I can't put my finger on what exactly I don't like about it

[kingmt]

I scored a deal on an Apex 2 barrel so after adding some detail to the shroud it is going to look something like this. Measurements on the Apex 2 tip might be off. I haven't received it yet.

[kingmt]

I didn't fully delete the abandoned bottom ram idea, but obviously I didn't finish it. It would have required leaving the body at full length which in turn would have made the hopper longer which probably would have made everything too long. That is the one issue I am afraid of, is that once I get the hopper printed and start assembling this that the hopper is going to make the reach to the front grip too long. I don't have gorilla arms...

Another issue is that the ram would be too far back to route air through the sear slot. So I would have either cut the sear slot farther back or done something interesting with the air routing. With that stacked rams when I cut the 1 3/8 inch off the body it actually lines up with the back of the sear slot.

[Meleager7]

What do you think of a design , where your rear stock hopper fills the spot where a tank would normally go? Then adjust the upper receiver accordingly. Figure out a spot for a Remote Line to connect as well ( this take on the design is remote line only setup)

[kingmt]

The problem with moving the hopper down like that is that in its current configuration that would put the vertical feed alongside the grip frame and it would get in the way of your hand. I originally put the hopper in this location to keep the feed tube path as short as possible and to use the hopper as a shoulder stock.



However I already had the thought of using a hopper like this on one of my other vertical feed guns, so I drew up this u-bend.
The left side would clamp onto the vertical feed tube and the right side would be in the guns feed neck. Again the white piece is an eye cover, so the loader would be pushing balls up the stack until the u-bend was full. The small tube on the inside of the clamping feed neck is a guide for the eye wires. The end result would look something like this

I have three different hoses for possible feed tubes and all of them have clear sections so the paint will be visible in the feed tube.

[Meleager7]

Your bottommost pic, I love it.

It's like an improved take on the AGD warp feed. I've had 2 warp feed setups, and I found it super awkward. It was really heavy with both the tank, and effectively 2 hoppers installed, and the weight of the gun biased to lean to one side, etc, etc.

It would be cool if this Bottomline Hopper could shift backwards more to become the should stock, and if the feed output could be switchable from left side or right side. That way a Righty player, could setup their feedtube on the left , out of the way of the right hand.

[Trbo323]

Since you are replacing the lower tube with pneumatics anyway, why not just flip the whole body upside down on the frame? That way you won't have to feed the paint up and then back down into the breach. This would also make the slight bump out on the left side for the feed instead of the right so assuming you are right handed it would make it so you don't have a bulge come out from behind cover first.

Run the air supply and pneumatic hoses also on the left side and you have an extremely clean right side

Sent from my motorola edge 5G UW (2021) using Tapatalk

[Levi]

I'm fond of markers that get the hopper off the top of the gun. This is really cool, looking forward to seeing where you go with this. Are you concerned with being able to sight down the top of the gun? That's what kept me from ever picking up a Dfender, the hopper was right where my face wants to be... just like a back bottle.

why not just flip the whole body upside down on the frame? That way you won't have to feed the paint up and then back down into the breach.

That's not a bad idea... you may have just inspired me to build an upside down MQ2, Warpless Rotor fed Cocker. Not that I need another project, lol.

[kingmt]

Monday I was getting ready to print the loader raceway parts and I decided to double check a couple measurements. It is a really good thing I did. I had placed the axle of the pully gear off by 2 mm, meaning that the pully gear and the agitator gear would not engage. Then I double checked where the gearbox screws into the raceway. Those points were off as well. Unfortunately those points weren't going to be an easy fix since I had assumed all three screws were arranged on the circumference of the same circle. So I said screw and I will print the gearbox with my mounting pattern. That started a cascade of changes when I started measuring the axle, gears, and bearings. I discovered that my original cut for the bearing at the bottom of the raceway was too shallow.


While I was at it I made changes to the spring carrier under the agitator to remove some of the slop in the original. The original spring carrier was designed to ride on top of a c-clip and I decided to remove that requirement. As a result the interior cavity of the agitator was reduced to make sure the agitator engaged the spring.

Then looking at some of the walls I had made 2 mm thick I realized that the walls did not need to be that thick so I started reducing them to 1mm thick. I also increased the radius of the upwards pipe bend to 25mm.




I am printing the first prototypes right now. The print will finish a little after 10pm tonight so I probably won't actually test it until tomorrow.

[_Boris_]

I have a boner for bullpups ...

1. instead of making the feed go up and then do 180, why not flip a top fed marker so it's fed from the bottom?

2. on P90, you can had storage in stock and feed balls through grip. Bolt will be up top instead of the mag, since it's wide add expansion tube there or use it for power pack.