Masterkey project

[withoutremorse42]

Have been working on this for a while. Wanted a rail mounted masterkey as opposed to the m203 style mount usually found.

Testing begins this weekend.

To mitigate shock to the mount, I'll be doing the following during the first round of testing.

1. Use aguila mini rounds
2. Hold the AR buttstock under my armpit, allowing the whole shebang to swing

Later I'll be adding a small rubber buffer in the gap between the shotgun reciever and the magwell.

Shotgun barrel is still over 18" and overall length is over 26".

Images are resized smaller as per Rob's post below


Pics

[rob_s]

Don't know how to direct link all the pictures

I'm glad of this, as those images are HUGE. If you resize them down to 1024 pixels wide or less I'll edit the post and make them visible.

Warning to those on slow connections considering clicking on those links, the images are over 3k pixels wide and may take a while for you to load.

[withoutremorse42]

Pics are resized

[rob_s]

Pics are resized

thanks. edited the first post and they should show now.

For future reference all you have to do is put [ i m g ] before the address and [ / i m g ] after (without the spaces) and the images will show up. If you click "edit" on your first post you should see those "tags" now where I added them. I think they might be in reverse order though?


Interesting project. Not my thing really, but I always like to see people tinkering and fidgeting. If I understand what you did correctly, you took a flattop riser, cut the riser off, drilled & tapped some holes in the base that was left, drilled through the top of the shotgun receiver, and then screwed up through the top of the shotgun receiver into the threaded riser base?

[rob_s]

Anyone ever tried that with something like a Stoeger striker-fired coach gun? I wonder if it wouldn't give a shorter overall package, especially if AOW'd. Wonder if there would be room for the barrels to stay fixed to the rail and the action to drop down to put shells in the tubes.

[continuity]

Nice. Interested in the results of your testing.

A friend and I am working toward the same thing. Found a pourable rubber compound for the "bumper" at polytek.com. One trail is leading to imbedding a scope saddle within a block of the rubber compound for the shotgun receiver connection and imbedding rail clamps on the other side of the rubber block to attach the whole shebang to the AR rails.

Also looking at modifying a 37mm flare launcher rail set to hold the shotgun receiver.

BTW, did you do anything else besides using a hacksaw to square the end of the SG barrel?

[Twinsen]

This is really interesting to me. Arevalo mounted a 37mm launcher on a rail system of his and used the 12ga adapter and said it was damaging his rail somehow. I don't know if the riser making a lot more contact with the AR's rail that it would fix that problem.

I do like the idea of using a coach gun, as the action is half as long.

Rob, I assume when you said AOWed you meant keep the pistol grip? Because if you attach an AOW to an AR with a stock, you've made an illegal SBS. But since you can't ever register a stocked shotgun as an AOW in the future anyway, I figure you knew that.

I wonder what would be best for a Stoeger coach gun mounted as a master key? They don't autoeject, so opening the action isn't difficult. And looking at where the triggers are, you cannot remove all of the grip even if you wanted to without doing trigger mods. I figure that you'd weld a 90 degree arm on the barrel release so that it can be operated from the side instead of reaching into the tight space between the shotgun and AR rail.

I can't make up my mind whether you'd want to mount the barrel or the action of the coach gun. Mounting the barrels and allowing the recoil to flow to the unsupported and lightened action might really cause some trouble quickly. But mounting the action would very difficult! You could cut the barrel release lever really short, so that it was just a circle, and then weld an arm to the top of that circle at a 90 degree angle so as to maximize mounting surface of the action instead of the barrel. Or I guess you could mount the barrels to the AR rail, and add more locking surface to the action externally. Like adding a slidelock, but locking the top of the barrels to the top of the action, because that would be the weak point for the unsupported action. The problem is that very few guns are made to handle being fired while mounted to something. Usually it's belt feds or artillery pieces that are overbuilt compared to rifles and shotguns and have a large amount of steel in the rear of the action. The pump has a big mounting advantage, but the action itself is so long that the barrel length suffers.

[withoutremorse42]

Interesting project. Not my thing really, but I always like to see people tinkering and fidgeting. If I understand what you did correctly, you took a flattop riser, cut the riser off, drilled & tapped some holes in the base that was left, drilled through the top of the shotgun receiver, and then screwed up through the top of the shotgun receiver into the threaded riser base?

Not really my thing either, just a fun project I've wanted to do for years. More of a novelty item than anything else. You hit the nail on the head as far as the machining techniques.

Nice. Interested in the results of your testing.

BTW, did you do anything else besides using a hacksaw to square the end of the SG barrel?

Test results were very positive. Used aguila mini slugs and 2.75" trap shot. Tiny amount of recoil and really didnt feel like much stress on the mount. I'm not planning on putting full power loads through it and I'll be inspecting it every time I shoot it for quite a while. Made a video, pretty dark but will make a youtube account and get it up.

After we hacksawed the barrel, my friend used a mill to angle the rib on the barrel down a bit the we used a file to clean it up. Can remember if he used the mill to clean the barrel tip as well.

As far as damage to the rail goes, the paint wasnt even scratched on the first round of testing but I'll be watching pretty close. The recoil was so minimal though, I'm not immediately worried. Felt like a 20ga with skeet loads.

[angelbeast6]

Would there be any way to use two rail systems to attach between each other. I'll take a picture of what I mean when I could but it'sthe same Idea as if you take a bottom railed handguard off and fit the rails between the existing rails on the top or side rails. Each notch will be filled. You'd just have to find a way to lock it in.

[withoutremorse42]

Would there be any way to use two rail systems to attach between each other. I'll take a picture of what I mean when I could but it'sthe same Idea as if you take a bottom railed handguard off and fit the rails between the existing rails on the top or side rails. Each notch will be filled. You'd just have to find a way to lock it in.

Yep, I've got a 7" stretch of rail that would work. I'd have to cut the ends off of it as they have slightly wider rail notches then in the middle. At that point you would offset the rails and be able to mesh the rails together. in order to lock them in, you would need to knock out 2 teeth on the rail that is attached to the shotgun, allowing you to put thumbscrew pegs though to the other side.

[angelbeast6]

Would there be any way to use two rail systems to attach between each other. I'll take a picture of what I mean when I could but it'sthe same Idea as if you take a bottom railed handguard off and fit the rails between the existing rails on the top or side rails. Each notch will be filled. You'd just have to find a way to lock it in.

Yep, I've got a 7" stretch of rail that would work. I'd have to cut the ends off of it as they have slightly wider rail notches then in the middle. At that point you would offset the rails and be able to mesh the rails together. in order to lock them in, you would need to knock out 2 teeth on the rail that is attached to the shotgun, allowing you to put thumbscrew pegs though to the other side.

I figured that MIGHT help with the issue of wearing away at the rails. Any chance of trying to make a setup like this? I have little metal working experience but would like to start on some projects when I get back form this deployment and was actually considering this exact "project."

[angelbeast6]

Oh, yeah, KUDOS! I really like the way it looks. Going to keep comming back to read about any progress.

[withoutremorse42]

Oh, yeah, KUDOS! I really like the way it looks. Going to keep comming back to read about any progress.

I dont think any progress will be happening for a year or so. I'm happy to have gotte it this far and I have some work on my form 4&1 suppressor&sbr that is in line first. Also running low on ammo so financially, working on the Key is on the backburner