MHP Arms Light Machine Gun

Prebuilt copies and kits in the future are available here:

https://www.frontlinefoam.com/product/the-mhp-lmg/
 

A nerf dart blaster that uses flywheels and a metal TT gearbox to feed and fire darts from a disintegrating belt. Currently using Banned Blaster or Daybreak wheels, with plans to add cages for lower power at some point. It's shared as is, without any support beyond what comes with the files. 

Hardware is going to be a mess. Lots of compression springs, extension springs, various lengths of m3 bolt. 21a and 10a switch, xt60 connectors, ALL METAL TT gearbox (do not use yellow or half metal), and a lot of filament. So much. https://www.amazon.com/gp/product/B0BLJW7FTW/ref=ppx_yo_dt_b_search_asin_image?ie=UTF8&psc=1
This is the rocker switch I used as a kill switch in the stock.

This is the filament I've used for the links. It's a pretty hard tpu, so it's flexible, but not soft exactly. You can also print them just fine in pla, but they'll break if you step on them.

https://www.amazon.com/dp/B074DV9JMX?ref=nb_sb_ss_w_as-reorder_k0_1_3&=&crid=1TULKIDXK7TW9&=&sprefix=tpu

The slots for springs are 6mm for the belt release, 8mm for the box catch and main cam, 9mm for the trigger, 10 for the pawl, belt retainer, and pusher. The extension springs are 7mm holes. 

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I will add more cages in the future. Currently it's a 40mm spaced single and dual, and a 39 mm single (for daybreak). I intend to add hurricane size wheels for lower velocity, and a 39mm dual cage. 

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I've reuploaded all of the files, into a single zip folder. That should keep the file organization a little cleaner. I've added another page to the build guide with details about hardware, although still no hard numbers. The cage and feed tray F parts on single and dual have been adjusted to mount better to the blaster, directly to the frame, with the wheel covers now being secondary and added after. Some of the builds have had crooked firing that I believe was caused by improper mounting, so I've worked to reduce the possibility of it. 

This fix now includes the untested full length parts!

Finally, all of the files have been oriented for proper printing when you download them. 

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Discovered the split grip parts had 4mm holes instead of 3, so that's been fixed. I have also been told that all the holes may print too big, being modeled at 3mm in diameter, so that's something to keep in mind as you print.

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Have tweaked the BB single cage. It looked like it was clipping slightly with the wheel cover. I've also added a single stage pulsar cage for lower fps (don't know how much lower)

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I have added a few tighter crush cages (daybreak dual, 40 to 39.5 crush dual) and relabeled the cages to indicate the motor spacing. I've also finally fixed the missing hole in the right mid frame, so the plate should mount on properly now.

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I've made a lot of small edits, mostly adjusting the screw holes to be 2.75mm. I've also added a few more extras like an MLOK handguard, a bcar ready dual 40mm cage, and a folder of test parts. I'll keep uploading partially experimented parts into the test folder. 

There is a new cam arm and belt grabber in the test folder that should help the feed mech actuate faster and sooner, giving more time for things to be aligned before the pusher gets to the links. There's also a 75 round box in there. And finally, I'm adding the step file for the box to here, so that you can edit it to be whatever shape and capacity you like. 

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It has been brought to my attention that there was an unintended bump in the rear left stage of the dual stage cages that might be affecting the positioning and alignment of the wheel. If you're building a single stage blaster with the dual cage, and having accuracy problems, that's likely the cause. I would recommend reprinting and rebuilding your cage if that's the case with the newly fixed parts I've just uploaded. 

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I've reorganized all of the files to help assist in choosing how to build the blaster. I've also added more tests to the test files, which include two new cam arms that are 5deg turned from the original. One forces faster cycling, but is probably harder on the gearbox, and the other forces slower cycling, but should be a lot smoother. Both are more or less untested, but if you're having feeding issues (that aren't the dart failing to push out of the link) maybe give one of those a try and see if it helps.