Joined: January 05 2017 Location: United States Posts: 189
Posted: March 16 2017 at 2:42pm | IP Logged
This is a polymer clay magazine well block that adapts an AR-15 to use STEN magazines. This version is made from Sculpey III polymer clay and steel. I will be making a CAD drawing to post as well with my intention being that this can be 3D printed and built at home. I just ordered a 3D printer so I won't be able to test this for a few weeks.
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backbencher
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Joined: February 26 2013 Location: United States Posts: 4151
Posted: March 16 2017 at 11:37pm | IP Logged
It would seem simple enough to cast & bake. I was thinking of using a pair of threaded steel rods interlocked as the ejector. Bake it in the clay, then cut the tops down to fit. Think that might work?
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PappaSunrise
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Joined: January 05 2017 Location: United States Posts: 189
Posted: March 17 2017 at 12:56am | IP Logged
It might but having the flat stock seems pretty dang sturdy.
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backbencher
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Posted: March 17 2017 at 8:50am | IP Logged
That's true. Also seems like a bit more fab time for the Dremel.
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PappaSunrise
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Joined: January 05 2017 Location: United States Posts: 189
Posted: March 17 2017 at 12:05pm | IP Logged
I'm almost done with the CAD drawing. It will just use a 1/8x.5" piece of steel for the ejector and a 1/4x3/8" steel piece for the latch.
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backbencher
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Joined: February 26 2013 Location: United States Posts: 4151
Posted: March 17 2017 at 1:14pm | IP Logged
If you can, it would be helpful if you also publish it as a .pdf
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PappaSunrise
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Joined: January 05 2017 Location: United States Posts: 189
Posted: March 19 2017 at 10:30pm | IP Logged
Put 150 rounds into my 5 gallon sand bucket and barely see any wear on the block. I used the opportunity to test about 15 different STEN magazines that I converted back to 32 rounds from 20 rounds. All worked flawlessly. I then decided to pour a handful of sand into the open upper receiver to test reliability. I did not have one single malfunction the entire test session. I then spent an hour cleaning the damn gun of all the sand and powder residue from my dirty reloads.
Also I noticed a flaw with the New Frontier 9mm bolt, the "gas key" bolts are not staked, or even loctited. They loosened up after only 150 rounds. After completely cleaning the rifle I reinstalled the bolts with red loctite and tightened them as much as possible without stripping them, hopefully that will do it.
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backbencher
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Joined: February 26 2013 Location: United States Posts: 4151
Posted: March 20 2017 at 7:08am | IP Logged
If not, you can stake them w/ a punch & hammer.
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PappaSunrise
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Joined: January 05 2017 Location: United States Posts: 189
Posted: March 20 2017 at 7:25am | IP Logged
I should have checked them first but I foolishly assumed they red loctited them. Not a big deal, it still ran like a greased top. I'm very happy with this upper. I saved about $300 by building my own barrel and magblock and assembling everything myself, I'd highly recommend it. Now I'll need to hit the range to test for accuracy.
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Paraquat
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Joined: March 14 2013 Posts: 893
Posted: March 20 2017 at 7:40am | IP Logged
Love it.
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bbstacker
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Joined: January 01 2014 Location: United States Posts: 6
Posted: March 20 2017 at 8:42am | IP Logged
Are you using any kind of depth stop for the magazine? I made one of those a while ago and had to flatten the dimples on the mags to get the correct depth to feed right. Bad idea I discovered. Mag can go in way too deep and stop the bolt. Ended up milling a "D" shaped notch on either side of the inside of the mag well to act as stops. All good then. No mods to magazines needed.
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PappaSunrise
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Joined: January 05 2017 Location: United States Posts: 189
Posted: March 20 2017 at 12:04pm | IP Logged
I actually thought milling a small flat on the magwell would be perfect, however I just barely flattened the dimples on the mags just enough to allow them to catch, having the flats on the magwell would be perfect though, but I didn't feel like permanently altering the lower if I didn't need to.
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