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Brigg

K-S03 mag fed APS shotgun

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So, I havent posted much about custom work since the last single shot pistol I made early last year, But I havent been sitting on my hands doing nothing. Aside from making that GBB Colt DOE smg, I've been  working on a few different designs. Some of them successful, some not, but Ive learned quite a lot about design from them.

 

So this thread is about my latest prototype, which i am calling the K-S03. As implied, it is the third prototype Ive done since the single shot pistol. K-01 was a gbb pistol that I haven't finished yet, and K-02 is a bolt action single shot APS shotgun. There was a double barrelled design in that period as well, but it never got to a functioning stage. I might try it again eventually though.

 

This is the K-02, the previous build. the pictures are all horrible because my phone takes bad pictures. Its a single shot, hammer fired, bolt action design that I built mostly to figure out how to extract and eject shells, which it does very well. Its just kinda oversized for a single shot weapon. I didnt bother posting a thread about it because I felt it was a bit unimpressive.But, it was a necessary step in making more complicated designs like the K-s03.

 

post-80387-0-09411900-1493489083_thumb.jpg

 

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K-S03 though is a magazine fed bolt action weapon. And while it has some similarity to the K-02, there are no common parts. Plus my machining improved drastically in the time between the two. The look has been described as "The *bramston pickle* child of an fg-42 and a sten"

 

post-80387-0-54466300-1493489492_thumb.jpg

 

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The magazine is of the rock and lock type and goes in on the left side of the receiver.The capacity, for now is 3 rounds per mag but once i start making more mags i want to bump it up to 4 or 5.

 

The system itself is rather simple. Its striker fired and cock-on-close, with the trigger simply tipping the sear, and a cross bolt safety that block the sear from dropping entirely. The stock is a quick detatch type, but later i may make other options like one with just a sling swivel, or a folding stock. The main functional bits are contained in the receiver tube so that it can be dropped into a wooden rifle type stock potentially.

 

Here it is disassembled. Not very many parts, though i left the trigger in place cause the safety is annoying to remove.

 

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That plug in the back is a buffer that prevents the bolt from going too far back. It has a 180 degree locking system that im really happy with (push in, twist 180 degrees to lock in place, reverse to remove)

 

It seems to work quite well with only a few hiccups, most with brand new shells which i guess might have stiff valves from never being used.

 

Here are some video of it being fired:

 

 

And this one from a different angle:

 

 

I think with some 5 round mags it may be even more usable on a field then the cam879, due to its significantlt faster reloading and more compact shape.

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I didnt bother posting a thread about it because I felt it was a bit unimpressive

 

Oh yeah, nothing interesting, just a bolt-action shotgun machined from scratch. Dime a dozen. See them every day.

 

Incredible work, and I really like the aesthetic of your second prototype- it's like a stubby Sterling with a handguard. Just looking at the design, if you added an action spring, couldn't you make it a straight-pull fairly easily?

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Yes, but itd be a pain to insert the magazine then because the bolt has to be open for that. Theres too much tension from the follower spring to insert it against the side of the bolt.

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I had thought about that originally, but my mags are much smaller for the capacity. Mostly because Im not trying to replicate anything real, so I dont need as big a mag with as long a follower spring.

 

When I get the 5 shot mags made, theyll only be a bit longer then the current one.

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That's gorgeous and if its as modular as you say with the drop into a rifle stock comment. could be an awesome mech for doing interesting shotgun builds that haven't been done yet this may sound dumb but would it be fairly simple to make pump action?

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That's gorgeous and if its as modular as you say with the drop into a rifle stock comment. could be an awesome mech for doing interesting shotgun builds that haven't been done yet this may sound dumb but would it be fairly simple to make pump action?

As a conversion you need the action arms from the pump to cam the bolt handle open and then push the bolt back, and then the reverse. It's doable but finicky, much easier if you designed it that way from the ground up.

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Given the fact that you're righthanded, wouldn't it make sense to make the gun "lefthanded"? If you feed it from the right and extract&cycle it from the left, you can operate the bolt with your support hand, instead of your trigger hand.

 

Other than that, *fruitcage* cool as all hell.

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I shoot lefthanded, but if i filmed it that way all you would see is my forearm and shoulder.

 

Either way i didnt see any reason to change the side of the bolt handle, thats how 99% of bolt actions are after all.

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I shoot lefthanded, but if i filmed it that way all you would see is my forearm and shoulder.

 

Either way i didnt see any reason to change the side of the bolt handle, thats how 99% of bolt actions are after all.

Would you consider requests? :) I need one.

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In between other projects, i took the ks03 out from the closet its been sitting in and did a couple of small improvements.

 

For starters, i hooded the front sight which makes the sight picture a bit nicer, i made a new, longer bolt handle thts easier to operate, and most significantly, i ditched the foregrip, added a bottom rail, and mounted a grenade launcher. Since i had intended to do  launcher at some point, this idea had been in the works since i first designed it. i just never did it.

 

Of course, i didnt make the launcher myself this time. I didnt really want to put the time into that, so it just a madbull one. It does the job though.

 

cVa4p6Ml.jpg

 

I still want to get back to the automatic gas powered aps at some point. But theres just so many other ideas in my head.

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While this isnt strictly related to *just* this build, i figured this is the best thread for it.

 

My main problem with repeating Aps builds so far has been magazines. My original mags for this bolt action one were complicated machined ones made from slotted together channel. They didnt feed well since the aluminum aps shell rims would bind to the feed lips, and the shells had a tendency to flip themselves up and fling themselves out. I tried Saiga mags as well, but they seemed overly large, and expensive. plus the ones available to me are crappy promag ones that dont feed at all.

 

So, i put some more time into it, and came up with a new magazine design, made out of heavy gauge steel.

 

wUCWVcJl.jpg

 

These are what i came up with. they hold four rounds still, but i can make one in a couple of hours, rather then a couple days. And more importantly, i can make them all functionally identical. They also feed really smooth.

 

So, now for my next aps based projects, ill be using this style of magazine. I will also likely go and retrofit the ks03 to take these new ones.

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