Meaker Mk 42 Medium Machine Blaster

BEHOLD! The Mk42 Chain Fed Half Dart Fully Automatic Blaster!

I'm releasing this for free, not on my etsy, due to the myriad of other designers whose work I have built upon with this one. While the final product is absolutely my own, there are portions and connections from Flygonial's Protean,  a mechanism inspired by a youtube video from a designer whose name I'll try to locate, extensive work with Mr. Heath Pants when trying to get his design working before ending up doing my own, links similar to those in a project by Toruk, and surely others.

No longer in beta. I've used this in a handful of CTNO comp-format public matches in CT and at the large-scale casual-format games in NSNW 5 in MA. I was able to use it on a field full of Spirit flywheelers and hold my own (capturing the flag a couple times!), I was able to play just about all day (~6 hours) in the rain and mud on a 1.5 Ah (1500 mAh) battery with muddy field darts, I got prone behind a rock on a hill and rained foam on anyone who tried to capture it. Twice when it jammed up because the (3-wall / 5% infill PLA) cage was melting from the volume of foam it spit out, I was able to pop the lid and enact repairs and get back into the game. This thing did well. There are some operating drills you'd have to get used to and it works differently than other flywheelers or springers. I'll detail the drills at the bottom of the post. I have made some changes as a result of the wars, those files are included: new ‘mag’ cog-wheel release, a longer lower rail to prevent the cog from coming out even if released, a “mag-bag” and associated blaster-side catch to make chains into ~120 round mags with gallon ziplock bags, and printed thumbscrew-pins that won't rattle out. A new cage I printed with 9999 bottom/top layers so it's all solid PLA, cut with more vent holes, and redesigned to grip 180 motors better - I recommend the 180's after I burned up 130's; the 180's have been going strong so far.

Build guide now included. Pictures of every step are also in the post.

1. A few dozen ½” #4 self-tapping screws (sheet metal, wood, plastitite, thread cutting, etc.)
2. Alternatively or additionally, assorted 3mm screws
3. 2x #4 countersunk screws are used in the design of the grip/battery tray, but these could be replaced with another type.
4. 2x Omron 2C26K or similar micro switches:A conversion piece has been included to use DB2 microswitches instead if desired.
5. For use with the included Ryobi Pack setup: Keystone 209 Battery Contacts
6. (optional, but desirable) ¼” Blade Connector / Quick disconnects.These things just snap right onto the Omron switches. The blaster is also designed to be stripped down such that having disconnects allows you to take it apart and swap components without soldering anything.
7. Several feet of +/-20ga stranded wire
8. Heat shrink
9. 2x 130-size or 180-size motors. Having run it in comp-style CTNO games a few times now, worker 180’s haven’t burned up but 130’s did.
10. 4x motor screws
11. 1x Greartisan DC 12v 550 RPM motor:On the motor, The 12v 550RPM is the version I used and appears to run about 10 DPS overvolted to 20v. AT time of writing, the motors are offered in 12v and 24v with RPM’s from 10-1,000. Higher RPM than 500-600 is not recommended, but lower could be used to increase drive force. DPM and RPM are almost 1:1.
12. A rubber band, elastic, or extension spring for the pawl.
13. Optionally, a round rocker switch Snap-in 20mm dia for the safety switch.
14. A few compression springs. Mine all came from an assortment. The stock and latch are both about 5/16” dia by ~1” long, the trigger spring is pen size / Protean/Gryphon size.

Now about those operating drills:

Just about everything about this blaster is different than a regular flywheeler or springer. So you will need to adjust to how it works and how to expect it to work.

Dart Loading: The major benefit is you can load all your chains whenever and leave them that way: chains don't really hurt darts from being loaded. I find stacking all my chains together on a table, linking them with a pin-dart into the joining links then filling the rest of the chain to be the fastest. I was consistently able to load my chain in about the time it took other players to load the same volume of mags. You can print all loose-links but I really prefer to have linked-links in sections of 8-20.

Linking: Although it's cool to run around like Rambo with a huge chain draped off of you, it is not effective at all. Ideally you'd have a mag-bag or a short section of 50 or fewer darts, and then once you got to your firing position link however many you'll use to the short chain from a carried bag, box, whatever. I could sling about one mag-bag's worth of rounds on my person but it was noticeably harder to maneuver and feed until I'd burned through some rounds. Similarly, don't make single chains longer than 30-50; it'll be too big and tie you up, especially when it's dangling on the outfeed.

Loading: Open the lid, Pull the pusher back, you should be able to grab the yoke part and it'll just go back. Put the first (empty, and it doesn't hurt to have a few empty at the start) link skinny side in so the link is on the cog. Slam the lid down with your left hand keeping the links in place from the feed tray side.

Firing: I kept this a two-trigger setup and have gotten questions about that. I can do double-stage triggers, but the prototype had one and I found there were times I wanted to control the mechanism separately from the wheels. This does mean it's easy to accidentally rev the wheels since the weight of the blaster pivots the grip. That is why I added the safety kill switch. Remember to use proper two-trigger firing discipline: Fully rev, then fire. With 18-20v behind it it should kick right up. IF you hear wheels sounding off immediately stop revving - you will nuke the cage.

Jam clearing: Stop revving, stop firing, safety on, flip the lid open. Rip the chain up and left, grab whatever dart/s are half-fed, slap the chain back down, close the lid, safety off and let it go again. If it keeps happening check your darts: this thing hasn't liked accufakes, but most modern narrow head darts (DZ Max, AF Pro, Workers, etc) are fine. If you modify the cage your milage may vary.

Stock: I don't use it as a stock unless I'm prone. I use it as a counterbalance so I can carry the balster. Others might need a sling, I haven't drawn up a sling mount but I'd put it on the stock's pic mount and through the loop of the ‘horn’ grip attachment. Might need to make one of those with a stock mount IDK.

Firing: Fire in bursts of 3-9 darts, then let it rest before firing again. This will help mitigate jams and overheating.

Cage swap: Get to cover and put the blaster on a good working surface. Pull the two pins holding the front flywheel cover on and rip the cage up, unlocking the lid as it goes. With access to the cage you should be able to assess if the wheels need prying up/loose or if the cage needs swapping. If the cage needs swapping, you may be out for the round unless you're carrying extra cages and you opted to install quick connects in the wiring harness.

Cog Wheel swap: I designed this to be doable but the only time it happened was an accident that broke the cog carrier. The cog has otherwise never had issues and never needed to come out of mine. If you don't use the anti-cog-wheel-swap lower pic rail, you can press the cog wheel / mag release and drop the cog out easily. To reinstall, push it up while holding the pawl back so the wheel can clear it.