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[ARCHIVED THREAD] - Masterkey Question (Page 1 of 2)
Posted: 7/26/2007 5:57:39 AM EDT
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- - I don't think they even make them at all any more. Most door kickers seem to prefer keeping them separate so that the carbine can be used without the added weight and bulk. - There are several legal issues and at least one ATF tax stamp involved with building one. Editted: I see that they are listed as available at www.impactguns.com/store/knights_masterkey.html for $1900 plus shipping and the $200 tax stamp. |
| Knights Armarment there is a company that sells all their stuff to the public that is still in Vero beach, I can't recall the name at the moment. Like it is said before there will be a 200$ tax stamp for the SBS that is attached to the front of the carbine! The ATF looks at it as a shouldered fired weapon so it is a SBS |
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There are lot of very cheap mounts around, but I wouldn't trust them at all. The KAC unit is nice because it attaches directly to the long axis of the shotgun receiver rather than using the shotgun's buttstock mount in the rear. Doing it that way allows it to mount right under the AR barrel, so there's little torque applied to the AR when you fire it. It also does not use the shotgun's barrel for mounting purposes, so you can remove it for cleaning without removing the whole unit. I saw a KAC Masterkey mount go for about $400 on eBay a couple years ago, that was the first and only one I've ever seen without the gun included. Randy Shivak used to make an almost idetical one years ago, but I think he's long passed that. He's at www.mr40mm.com, you might drop him a line if you haven't already and see if maybe he could make you a one-off mount or maybe he still has some lying around. But if it's not either a KAC or Shivak mount, I'd not do it at all. |
| I used to make a mount called "The Doorknocker". I have since fallen away due to a permanently trashed back. I was milling them by hand from 7075 and 6061, then having them hard-coat anodized to mil-spec. You did have to drill and tap 4 holes in the top of your 870 receiver. I eventually wanted to provide a matching 1913 rail to mount in its place for when its no under the AR. I've only had 3 or 4 requests for them in the last 3 years, so I don't think it is economically viable for me to sub them out, at least right now. |
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I already checked w/ Shivak. He's not interested. Impact won't sell the adapter alone. As far as the SBS, I'm not really worried about it. My 18" 870 added to an M4 is about the same length as a standard 20" A2, stretching the confines of "CQB", but certainly still viable. Also, I saw the MM12, built by Sage, Int'l. What about it? Looks almost identical to the KAC. Does it have any sort of reputation?hinking.gif |
What, hypothetically, would it cost you to tool up again? Would you be interested in selling a set of plans or blue prints? |
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I have the tooling. I just can't mill the stuff by hand anymore. All I did was take a DARPA M203 Print, chop the barrel rail and mech housing part, and add the Rem 870 receiver radius along the bottom. Figures like this: 11" Bar of 1.5"x1.5" 7075 T-6 $11.00 3.5 hrs of machine time@$35/hour GI M203 Mount Bracket with Insulator Bushings $34.95 plus ship (Sarco) 3/8" 10-32 Threaded Inserts, 2 each $2.00 10-32 Cap Screws x4 $0.50 10-32 Dome Head Cap Screws x 2 $0.15 Mil-Spec Hard Coat Anodize: $75/lot, up to 20 done in a lot. I had a special ball end mill ground to match the contour of the Rem 870 receiver. If you look at the top of the Remmy, it has a radius on the sides, with a small flat on the top. I will cost me about $125 to have a program written for a shop to mill them on a Mitsui milling center, probably with a per piece price of $65. x10 pcs minimum, plus a $100-125 set up fee, for no matter how many I have cut. Add that to the hardware above, and as you can see it gets very expensive. I was selling mine for $130 shipped. I would have to charge at least $175 each to make it worth my time. But the advantage is, you can use your own Rem 870, instead of paying $1400 for a KAC Masterkey, plus $200 transfer tax, and that's if you could find one. ETA: This is just a good approximation. Let me drop off my print to my machine shop guy and get a better quote. The advantage of me subbing them out would be you get a true M203 dimensioned arc across the top vs. the 30 degree angle I was milling them at. |
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I have the mount for it, I alsmost sold it to someone until he mentioned he wasn't convinced these four screws and holes will stand up to the recoil... I got it from another member here, never used it.  So Stoner63 you're the one that made this? Haha, that's cool, the maker of this is also on ar15.com 
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Count me in for one. |
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Stoner63, what kind of numbers would constitute a group-purchase worthy of your time and resources? If you don't mind offering an elaborated price-quote. |
So does it use a knights QD 203 mount? Any pics of one installed with the 870? I could very well be in for one.... S.O. |
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I've got some pics in storage. I've moved twice since these were made. All you have to do is some tensilary strength formulas to figure the shear point of the 10-32 screws....yada, yada, yada. 80% of the recoil is absorbed by your body. I shot my prototype under my ol' M4 with 3 inch magnum slugs and buckshot, until my shoulder couldn't take it anymore....then I starting shooting the vaginalized LE Reduced Recoil Loads (joking, they're not vaginalized). I don't recommend you shoot the 3" magnums, even stated so in the info. Because the shotty is way below the stock line of the carbine, it yaws or whatever the term is, in a vertical plane. Low recoil loads aren't too bad, though. I'd still rather being carrying the M249 SAW Para instead. |
It goes by Lawmens and Shooters Supply. Its right at Oslo Rd. right before the I95 overpass. There isnt too much out there. It has no signs. |
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Machine Shop Contact #1 is out, left the state, went to OR. Guess I have to send Paulie and Guido to go collect some debt for me. joking..maybe. Machine Shop Contact #2 may be better, price wise. Its a voc tech program, they always need stuff to use for training. I need to send my TDP down to Pueblo to get a quote, on 12 and 24 pieces. KAC M203 Quick Detach Mount should work with mine because its the same spec as an M203. I don't have a rail system to mess around with to work on a 1913 rail mounted version, with a side clamp bar like the carry handles. Unless somebody has a KAC RIS or RAS they don't mind loaning to the project. Don't worry, I'll only attach a modified Mossberg 9200 Jungle Gun, to make a street sweeper. So, do we have about 9 pieces spoken for? |
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Just a thought, but.. A Mossberg 500 is a bit lighter, and would work well in this application. Another advantage is that the magazine tube unscrews (vs being soldered in on the 870), and one could change the barrel as well as the magazine tube itself to various lengths. But either way, it's cool. |
But the safety will be mighty difficult to reach with a masterkey set-up... |
Yeah, I see what you're saying. Cavarms makes or (made) a safety button for the Mossberg that sticks out on both sides to be used with their AR stock adapter. I think it might work. Here it is. |
Or you could use a Maverick (Mossberg's bargain label). The Maverick 88 is just a Mossberg 500 that has a crossbolt safety in the triggerguard instead of on top of the receiver. Everything else is standard Mossberg. |
26" OAL but on a pump/semi shotgun the receiver length generally makes it over 26" without a stock. Generally the only time OAL becomes an issue with shotguns is with single shot or doubles because of their short receiver length. The added length of the AR counts torwards the OAL of the shotgun....as long as it's not quick detatchable AFAIK. |
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I was the OP, changed accounts since then. I just got mine back. It isn't SBS'd yet, but one day....... Overall, I'm satisfied with it. Range sessions with it are very beneficial: shooting and weight-lifting all rolled into one  .Plus, it's great if you like attention. I open the case, and get everything from, -"What the hell is that? ]" -to "Oh, f()[{-yeah[  ]"-to "Where'd you get that? ]"One guy looked at it and simply said,"That's just heathenism." Since its completion wuold have been impossible without the help of this fine forum, I refer all inquries to ARF.com. I'll try to post some pics later today, and I'll be wearing Nomex if I do 
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Please do, and can you tell us about your method and how much it cost? |
[ARCHIVED THREAD] - Masterkey Question (Page 1 of 2)
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