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Posted: 5/28/2015 2:08:18 PM EDT
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Before I start, I know that I should (1) move out of NY, (2) not comply and/or (3) just buy a Remington 760/7600. However, they are (1) not an option, (2) not what I'm willing to do at this point and (3) not as much fun, respectively. So, with that said, here it is ...
My goal was to make a free-floating, pump operated upper that utilizes as many stock AR parts as possible, thus allowing for the same level of customization. My reasons for this stem largely from the fact that Rochester, which is second only to NYC is trampling on our 2nd Amendment rights, does not allow for more than 5-round magazines in any semi-automatic, centerfire rifle. However, manually-operated (pump, lever, bolt, etc) are allowed the NY-legal 10 rounds (though, .22 tube mags can actually hold more.) Also, being in NY, manually-operated allows me to have "evil" features like a pistol grip, collapsible stock, flash hider, AFG and black paint (just kidding). Onto the build itself: 
Here's a video of some dry running empty and with a 5-round mag of snap caps (haven't put live rounds through it yet.) Mega 3H Lower Geissele 13" Mk4 M-Lok (tab modded to fit ASA upper) ASA Side-Charging Billet Upper Voodoo 14.5" Gov. Profile Barrel w/ Pinned Manimal Voodoo Life Coat LPK ALG Quality Milspec (QMS) Trigger Group UTG Pro Buffer Tube JP Silent Captured Spring MFT Minimalist w/ Paracord Braid MFT Engage Pistol Grip w/ Largest Panels Magpul AFG (Gen 1) Magpul BUIS The only mods from a standard AR are the custom-made (and at this point, rough prototype) pump carrier (which is keyed to the free floating hand guard and actuated the BCG through a physical op-rod), a milled slot connecting most of the M-Lok openings on the bottom of the rail for the AFG mount to ride in and (soon) a steel gas block mounted backwards forward of the pump carrier's action. Other than that, the parts are all reconfigurable. I chose the side charger to cycle the bolt when prone or shooting off of a rest. Unfortunately, the op-rod likes the gas key so much that they move together when the side charger is actuated (being non-reciprocating, though, the side charger does not move when the pump is actuated), even though they are not supposed to be connected. I do have the front piece of pic rail to rest it on, however, so I haven't decided if I will fix that problem or not. It does have the advantage of acting as a forward assist this way. It's taken a lot of playing to figure out the best configuration, so I will eventually make a second carrier, using what I've learned to make it even better. The AFG could also be remade, since I took off more material at the back end than I ended up needing to. |
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Thanks.
I talked with Dave at Bentwood Gunsmithing (UMOS designer) about building something like this, but they were backed up with work, so I tried it myself. They had a different set of criteria when they designed theirs and it does what it was designed to do very well. |
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Quoted:
I have NO use for a pump AR. That said, I like the "custom" build. Now I might want to build one. I do feel for you guys behind enemy lines.  I wish that I didn't have a use for one ... that I could simply put a gas block and tube in there as intended ... that we didn't have to choose between making our ARs either ugly or functionally neutered ... That said, I enjoy this type of thing and highly recommend it to anyone with the knowledge, tools and curiosity (I'm a mechanical engineer, so naturally have all three.) I'll post updates as they come. |
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Dude, you should have patented it or something. It would be tough to do since you used COTS hand guards. But man, that's pretty cool. We in these crazy states sure have to jump through balywicks to keep our firearms and keep them legal.
Great work. Maybe approach one of the vendors and see if they can market it. Good luck. tell us how it does at the range. |
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Thanks for the support, everyone.
Quoted:
is the angled foregrip the pump handle, or is it a single shot sidecharger? when its in battery is it locked up like a 12ga? (can you just pump out a live round without unlocking the action?) i'd like to see the mechanics. Quoted:
is the angled foregrip the pump handle, or is it a single shot sidecharger? when its in battery is it locked up like a 12ga? (can you just pump out a live round without unlocking the action?) i'd like to see the mechanics. As the video shows (link in text in first post), the AFG is the pump handle. It is attached through a slot on the bottom of the rail to the pump carrier inside the handguard, which is in turn attached to the bolt carrier via an op rod. I trimmed off some material from the back of the AFG, but as the design progressed, it turned out that I took off more than I need to. My plan is to make another at some point. It does not lock in battery. However, it has a full-strength buffer spring pressing the bolt carrier and, thus, the bolt into battery. It takes a conscious effort to move it rearward. While I have not live fired it yet, I don't foresee this being an issue. Quoted:
Dude, you should have patented it or something. It would be tough to do since you used COTS hand guards. But man, that's pretty cool. We in these crazy states sure have to jump through balywicks to keep our firearms and keep them legal. Great work. Maybe approach one of the vendors and see if they can market it. Currently, my aspirations are only personal, but I can't rule out that they might turn commercial at some point. With my prototype and their design, Bentwood (makes the UMOS system), could probably do it pretty easily. While the Geissele has some advantages, the same basic idea could be applied to others. |
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Quoted:
Very nice job........have you figured an interlock to keep the action from cycling till the round is fired? That will be a must for a commercially viable version. Rudy Thanks Rudy (big fan of the DI45, btw). I haven't really thought about how I would lock it in battery since the buffer spring is strong enough to keep it from coming back due to just a resting on the foregrip or even bumping it. You really have to consciously decide to start the cycle. So, the worst that should happen is the shooter tries to do some sort of rapid fire, doesn't time the trigger pull correctly and ends up ejecting an unfired round (since it is not supposed to fire out of battery.) For now, I can live with that. We'll see how it goes at the range. As for a commercial version, the UMOS doesn't have such an interlock either. The Troy Sporting Rifle does, though. Something to think about ... if I try to sell it. |
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