Sunday, July 20, 2014

The 9mm AR15 conversion

As I covered in my last post, the 9mm carbine is a nice alternative to the 5.56x45mm standard rifle round. Cost of ammunition, recoil, and noise, are all lower when you switch to 9 mm. Some ranges only let you shoot pistol calibers and will not even allow a rifle caliber on the premises.Penetration, overshoot, and backstops all have to be taken into consideration as well. Whatever your reason, the 9mm carbine just makes sense in a lot of scenarios.
I've been looking into a pistol caliber AR15 for some time, but due to the excessive cost, I've never gotten too serious about them. Just from a glance online, the prices are insane:
1. Bolt, about 200 bucks
2. Barrel, another 150-200 bucks
3. Magazine block, 50-200 bucks
4. Heavy buffer and heavier buffer spring, 50-75 bucks.
And this doesn't cover mags, or even the dedicated upper receivers.

No matter how you look at it, the cost of converting a standard AR lower to 9mm is almost the same price as an entry-level AR15. While you will eventually save that much money by shooting the inexpensive 9mm ammo, it might take you a long time.

Longtime readers of this blog will probably remember that I am
1. A cheap bastard frugal man.
2. Resourceful
As such, I felt it was time to look into caliber conversions on a budget. My ideal weapon conversion would of course, have to be inexpensive, reliable, and perhaps even adaptable to different pistol calibers, such as .45 acp, 40 S&W, and 9mm luger.
I think I have managed to put something together that will accomplish all of the above.





The magazine is from a Sten, and these mags have been used to feed 9mm, 40, and 45, so it's capable of being swapped from one upper to another.


Starting with a normal Anderson lower, I added a few parts.




A standard stripped upper, no forward assist or ejection port door are attached. They're not needed, and I will probably either machine a "featureless" upper down the road, or I'll get an Anderson upper that has no provision for a forward assist or a port door.




The barrel is a given, I started out with a "gunsmith blank" from Green Mountain Rifle Barrel. I have used dozens, if not hundreds of these barrels in different calibers, and have never had a problem with the quality.
The barrel set me back about 30 dollars, then it needed to be chambered and profiled (turned to shape on the lathe)





The "mag block" is a piece of cold roll scrap I had laying around. It takes up the remainder of the room in the magazine well, and has a release lever for keeping the mag in place.




An ejector was attached later, but here's the basic spacer block attached to the lower.



The bolt was a heavily modified Suomi bolt with a floating firing pin installed. This bolt was almost too light in this configuration, so I came up with a quick, easy, and cheap solution that uses the original buffer and recoil spring. I found some 1" round bar stock and cut a section of it to put in front of the buffer. It acts as a weight to slow bolt movement, and also shortens the stroke of the bolt by that amount. We'll see how it runs.





After slapping the gun together, I liked the way it looked with the plastic forearm and carry handle, but figured a free-floating handguard and a cheap red dot sight would look even better.


I think I was right.








The final tally of expenses revealed that I had spent well under what a normal aftermarket kit would run, and I may have actually assembled a kit that can be configured in multiple calibers.

Range report coming soon.

Thursday, July 17, 2014

Powder coating: It's an electrically charged awesome.

One of my biggest hurdles in gun building, believe it or not, has been coating the finished product. While there are a variety of different products on the market, each one has it's own issues for a garage builder like me. Bluing, parkerizing, duracoat, cerakote, spray paint, and a number of others, each with their own inherent benefits and detractions. Most of my guns have been coated with the Krylon touch, but that leaves a lot to be desired. My shop is almost too dirty to do spray coatings like Duracoat in, plus the fumes would get to be an annoyance.

Recently, I was in Harbor Freight, and saw that they had their powder coating set up on sale, and I had a 20% off coupon, so I walked out a happy man. I figured I could afford to lose that much money if it didn't work out, or I couldn't get the hang of it. I already have a sandblasting cabinet, so that part of the equation was covered. All I needed was an oven that could reach 450 degrees.
A quick stop by my local Chinese wholesale mart (also known as Wal Mart) netted me a toaster oven for about 50 bucks that is large enough to cook most of my powder coated parts in.


Powder coating is a pretty cool process, in that it sprays a positively charged cloud of colored powder at an object that has been grounded. The powder is attracted to the part like a magnet, and the powder is held in place via static electricity (more or less). The part is put in an oven and the powder is melted and fused to the part. It requires a very clean surface, and media blasting the part beforehand to get some "tooth" for the coating to adhere to.

I've been working on a 9mm conversion for the AR15 that is inexpensive and doesn't require any modification to the rifle. Most of the conversion kits out there are very expensive (200 bucks for a bolt, 100-200 for a barrel, 50-200 for a mag adapter, etc) and since I can build a complete AR rifle for less than 400 bucks these days, that just didn't set well with me.
So, I needed a conversion kit, and true to my typical nature, I don't want to spend much money. A starting point would be magazines. The Colt mags are great, but expensive, and are really just Uzi mags with a mag catch milled in, and require an adaptor. After digging around, I found a reasonable solution: Sten mags. They're cheap, hold plenty of ammo, and can even be used with other calibers. The best part? They fit in the magwell quite nicely, and only require a filler piece on the rear of the mag.
I took 3 mags out of the stack of Sten mags that feed my Sten, and dedicated them to this purpose. Since they were rusty, greasy, and altogether cruddy looking, I figured they would be good fodder for this project.

The mag block, fresh out of the mill.


A Sten mag in place with the block. The block is held in place by the AR mag release.


Mocked up right purty.

They are a good fit for the AR pattern rifle. A bit of a bitch to load, but there are plenty of mag loaders on the market that will work with the Sten mag.
Since the rifle was going to get refinished, why not the mags?


Now, these mags were all military surplus that had been dunked in cosmoline and stored for years in a vault in somewhereistan. The oil from the cosmoline had soaked in pretty good, and made life a living hell. I couldn't get all the oils out, no matter how hard I scrubbed. I finally media blasted the mags, then put them in the oven at 450 degrees for 20 minutes.
Turns out, the oil seeped out of all the hidey-holes, and I was finally able to remove it all. I put the mags on a fan to cool, before dunking them in solvent.




After the mags had cooled, were degreased again, and blasted again, I put them in my hi-tech powder coating booth (the box the powder coating rig came in, with a metal hanger stuck through it) and sprayed some Harbor Freight matte black powder on them. That stuff is about 6 bucks for a pound, and it takes about a spoonful to do a mag or three.



Believe it or not, this is the coated mag.


While they're getting powder coated, I turn the oven on to 450 and let it warm up. I then hang the three mags from a rack that came with the oven, and set the timer to 20 minutes.

Within a minute, the powder melts, and gets a very glossy and orange-peel-ish look. After 10 minutes, it's very evenly coated, with a nice gloss. As it cools, it dulls slightly.


Giving the floor plates the same treatment.


The finished, unassembled product. Ignore the water droplets on the floor plates.


Assembled, with a light coat of gun oil spread on with a towel.


Finished, and installed in the blurry gun.


The finish is very, very tough. It does not scratch easily, and solvents won't touch it. The best part? Over 6000 different colors available, and it's very, very cheap.
I don't know how it would hold up on a barrel or a similar object that gets very, very hot, but so far the mags and receivers I have coated have held up well, and still look good despite a few trips to the range and a lot of shooting.

This weekend, we will find out how well my 9mm conversion works; more on that later.

Tuesday, July 8, 2014

A new direction

Well, as if I didn't already have enough on my plate.........

I've decided to hang out a shingle and establish a actual business in manufacturing.
My LLC paperwork is complete, now I will be sending in my paperwork to the BATFE to operate as an 07FFL soon.
Hopefully, this will allow me a little room to blog about some new ideas and projects that I've been wanting to complete, but just haven't been able to address due to legal concerns.

More as I get to it.

Tuesday, April 22, 2014

Projects.......we got 'em. NOW WITH MOAR PKM PICS

For those of you who still come through here from time to time looking for.....well, whatever it is you look for, I thought it worthwhile to put up a picture of a recent project that has finally been (mostly) completed.


Say hello to my little friend.










That is a Soviet-era PKT that I built into a PKM copy. It fires the 7.62x54R cartridge. It was originally solenoid fired and pintle mounted, but is now a shoulder-fired rifle.

- I did a reweld on the receiver, and welded in several blocking features to keep it semiauto only.
- The FCG is all AR15 parts with a Wolf power hammer spring.
- The lower receiver that houses the FCG was machined on my CNC mill from 1" thick steel billet, and has a very nice maple grip from www.red1stocks.com.
- Buttstock is original surplus from www.Desertfoxsales.com
- The barrel originally was much longer, larger diameter, and had three holes drilled into it to demill the barrel. I threaded, plugged, and welded two of the holes, then cut about 8" off the barrel before turning it down on the lathe, then fluting it on the mill. It weighs about 60% what it once did, and looks much better, in my opinion.
- Sights are not installed yet, but will be salvaged from an AK rifle.
- Bipod is from an RPD and mounted in original PKM location. I will likely trim the legs down later.
- I am working on a custom-machined muzzle attachment based on the original flash hider.


I will try to put some more pics up later, including some pics taken during the build process.




Friday, March 21, 2014

Another round of....you guessed it.....guess that barrel!

In lieu of useful, informative content, I challenge my readers to a much easier game of "Guess That Barrel".

This one should be pretty easy, but it it's not, I'll give you a hint.

This one is on the bucket list of almost every gunny, and it's an iconic American piece of machinery.


Thursday, February 20, 2014

Guess that barrel?

Not dead yet, just too busy for blog.

How about a game of "Guess That Project", using a pic of a barrel I machined?

Tuesday, December 17, 2013

Another Uzi how-to video.




Here's another DIY video, showing the average builder how to convert a SMG uzi bolt to a semiauto closed bolt.
Enjoy.

Friday, December 13, 2013

Machineguns are awesome.


Well, my semester finals are officially over, thus giving me back some free time once again.

I've got some updating to do and some new projects to document, as well as some parts reviews to do, so hopefully I'll have the engines running here again soon.

What did you do over your Thanksgiving weekend?

Me?

I had an 07FFL SOT come by the house with a Suomi kit built into a post 86 MG.

There is no doubt in my mind that it was likely one of my favorite machineguns I've ever shot. Shooting my semiauto Suomis is just dull and depressing now.

Here is a collage of the different machineguns the FFL brought with him, a H&K 51k, a H&K 53k, an M16, and the Suomi he built.









Thursday, November 14, 2013

Machine tools, going automated through the power of Computer Numeric Control

Been away from this for a while mainly due to school and work. I haven't had much spare time, and what time I've had has been spent on other things.

Anyways,
I've read a couple of posts from my good friend The Silicone Graybeard over the last few months that originally spawned this, but haven't had time to finish it.
I've had a lot of folks pick my brain along the way about what kind of tools they need to build their own firearms, and I've often said the same thing to a lot of them, "It's not what tools are in your toolbox, it's what you do with the ones you've got in conjunction with the most important tool of all, the one in your head. Anything beyond that just makes the job faster."
I bought a large lathe and a medium-sized mill instead of relying on lots of files and hard labor, but back when I started this blog, I didn't have a mill, I barely had a lathe, and I didn't have much experience. What I did have was the desire to build a .50 BMG rifle inexpensively, which I did do most of without the large mill and lathe.
Now that I've been doing this for a couple years (I think I started blogging about the .50 in late 2010), I've had the opportunity to pick up a number of different tools and improve some of the ones I already have. Here of late, I decided to upgrade my milling machine to CNC control. This will do the same thing that most any milling machine can do, but it will do it under computer direction and control. It also means that I can design something on my PC, then send it to the computer and let it make the part while I work on other things.
I looked at the cost of doing this, and figured it would be worth the trouble.

For those of you interested, the electronic hardware necessary to do this was about 150 dollars per axis, and the mill has three axis, X, Y, and Z. X is the longest traveling axis on my machine, and has about a foot and a half of travel, good enough to do large projects. Y is the back-and-forth axis, and has about eight inches of total travel. Z is the up-and-down axis that the cutting tool is attached to. This axis has about 5 inches of travel.
Both X and Y axis have acme thread screws that permit movement when the mill is new from the factory. Acme thread is very useful for high torque and high force applications, in part because the thread has a square appearance, rather than angled like the typical nut and bolt threads that you see.
Better than the Acme threads are what's known as "ball screws" and "ball nuts". Instead of having threads that mate to other threads, the "ball screw" has threads that are squared like Acme thread, but have a radius at the base of the thread leade. The "ball nuts" contain a number of small individual ball bearings, and the bearings will circulate inside the nut itself. These bearings fit in the radius of the screw leade, and allow for smooth travel, with very little backlash. I changed my mill over to ball screws for the CNC application. The upside of ball screws, as previously mentioned, is smooth travel and very little resistance to movement. The downside is that the screws offer little resistance to movement, so unless something is used to lock the screws in place, such as a engaged motor, you can literally push the mill table around by hand.

The Z axis is now an odd concoction that uses a rotating ball nut inside a timing pulley to lift the quill up and down. It works, though it is as ugly as a burlap sack of rusty nails.

I have a CAD program for designing my parts, and CAM program for taking the drawings from a simple image to a toolpath via a genre of computer language known as "G code". This code tells the computer what you want it to do, from cutting speeds, rapid movement speeds, cutter spindle speed, turning on coolant pumps, changing tools, etc.

ViaCad is what I draw and model my parts in, and MeshCam is what I use for converting those drawings to tool paths.

We have all at one time or another, seen a AR 15 lower receiver. On this blog, I have previously outlined how to manually machine a 0% lower forging into a finished receiver. Well, I now am able to clamp a forging into the mill and have the machine make all the critical measurements and cuts.
Observe:

Cutting the top deck on the lower forging.

Cutting the magazine release slot.

Cutting the pistol grip area
Cutting out the magazine well

Cutting the bolt hold open slot on the top deck.

Cutting the FCG pocket

Cutting the front take down pin area.




It took a little while to get to this point. I've broken a few end mills and ruined a couple of forgings getting this far, but the end result is very nice to behold.


So, that's a sample of what a CNC milling machine can do. It has made life much easier when it comes to building simple things like AR15 lowers, and has also made it easier to do much more complex things as well.

Monday, September 16, 2013

A reader's Suomi M31 build.....

A reader sent me pics of his M31 Suomi that he built using the pics, instructions, and drawings found on my site. I also machined his bolt, firing pin, and striker for him a while back.
I thought this was a fine example of a home-built firearm. He spent a lot of time working on the fit and finish. It shows, since the receiver is a sleeved reweld.
According to him, it runs 100% and is smooth as butter.

R.T., two thumbs up from this redneck on your build, and thanks a ton for sharing it.

Monday, August 12, 2013

How to build your own Uzi from a parts kit. Now a motion picture.

No sooner than I got the last parts in that I needed to finish my Uzi,  than a new kit arrived on my doorstep. This kit is a German/European kit, and is in great shape. It also came with what is known as a "center repair section" from the good folks at Global Machine and Tool. The repair section speeds up the build process by a factor of 10 compared to piecing together a bunch of demilled receiver chunks. You take some measurements, square off your front and rear receiver pieces, weld them on the ends of the repair section, (making sure your blocking bar is welded in as well), and then weld in a couple of small semi-auto pieces like a feed ramp and a stock mounting block, then rivet in an ejector, and you're done.
An inexperienced builder could finish an Uzi in a matter of hours if they used the GM&T repair piece.

Anyway, here's the video. I'm about as much of a film artist as I am a gunsmith, which is to say, not much.
Enjoy.

Sunday, August 4, 2013

Modifying the Uzi bolt to semi auto

Continuing one with our Uzi project......
The SMG bolt must be modified in such a way that it can no longer be used as a fully automatic bolt, and can only be used to fire semi automatically. One shot per pull of the trigger, and all that.
This is probably the hardest part of building an Uzi, and requires the use of a milling machine. A drill press and a cutoff wheel could be used, but would also require abundant use of a file to get everything spot on.
Semiautomatic bolts can be purchased, however, in lieu of machining your own. I'm a real tightwad when it comes to stuff like that, and I own a number of machine tools, so I just forgo spending the money on the finished parts, and instead spend my money on screwing up one or two parts before finally lucking out and getting one right, in effect wasting twice the time and money that could have been spent on simply purchasing an off-the-shelf part.

Starting with pics from a previous post, we took our annealed bolts and drilled a hole in the rear of the bolt, all the way through to where the fixed firing pin was. This allows for a floating firing pin to be used.
We also drilled a 1/4" hole in the upper right corner of the bolt. This is to save us a little time on the mill, down the road.





Next, the sear "feet" on the front of the bolt are welded up. This is so the original sear will no longer control movement of the bolt. I laid a ton of weld on these areas, just so I knew that I wouldn't have to go back and add more after machining the welds down flat with surrounding areas. Hence the "gob-welded" look.
On the left, an un-modified bolt, in the middle, a welded bolt, and lastly, a bolt with the welds milled and sanded smooth.


Next, we will be revisiting that hole drilled in the upper right corner of the bolt. This hole is there so we can mill out a slot on the right side of the bolt and the bolt can now clear the blocking bar in the receiver. I milled this out with a 1/4" end mill, then started filing to get it to clear the bar by a few thou.


Here is more of the bolt with appropriate areas filed and sanded flat.


Now, we need to machine a large chunk out of the bottom right side of the bolt, so the semi auto sear has a place to ride. I thought I got a pic of this entire process, but it seems I only got a half-way-through pic.


After a couple of failed attempts to machine the striker (mainly because my milling machine is in pieces at the moment, getting some upgrades), I ordered a striker for the gun.

Since I'm building a carbine, the gun must have a 16" barrel, and have an overall length of 26" with the stock collapsed. In order to facilitate that, I had to make sure my barrel was long enough. I turned my barrel out of a 11" barrel blank, and machined a barrel extension 7.5" long that I welded on to the 11" barrel to make it a permanently-legal carbine barrel. Since I think the Uzi carbines look ridiculous with the "ant-eater snout" barrels, I used a piece of 6061 aluminum tube to make a fake suppressor, so the Uzi wouldn't look quite so dorky.
Here is the finished, raw metal Uzi, with the fake can on it. I intend to do a little machine work on the can to make it resemble a real suppressor, more than it does now.

I'll have pics up in a few weeks of the finished product, and hopefully a range report.

For the purposes of 922r, I have the following parts to replace the original imports.

Receiver -US
Barrel - US
Mounting Blocks (trunnions) - IMPORT
Bolt - IMPORT
Trigger housing -  IMPORT
Trigger - IMPORT
Sear - IMPORT
Disconnector - IMPORT
Buttstock - IMPORT
Forearm/handguard - US
Magazine body - IMPORT
Floorplate - IMPORT
Follower - IMPORT

That brings me to 10 import parts, which means I am legal and ready to go. I'm waiting on the striker and forearm/handguards to arrive.
There was once a letter from the BATFE that the Uzi had an operating rod that was subject to 922r, but they have since changed their opinion and said that the Uzi did not have an op rod, which is altogether correct.

More on this project as I get to it.........

Thursday, August 1, 2013

Converting the Uzi fire control group to semi auto.

Back on the Uzi carbine I'm building........

I ended the last installment of this project with two receiver sections that had been welded together out of four sections. Before I could go much further, I had to weld a blocking bar in place on the receiver, which is shown in the pictures below.
Once the blocking bar was in place and burned in, I took another receiver section from a demilled Uzi receiver I got from Apex gun parts. The receivers they sell aren't good for much, but they do have the necessary center section with the ejection port.
Here is the receiver in one piece. There is still a little grinding and sanding left to do on the welded areas, but for now, it's legally a firearm.


There was a small amount of burn through on the welds that hold the blocking bar in place, these were ground out with a Dremel tool.



Another shot of the quasi-finished receiver.



Now, as with any semi-auto that is built from what was originally a machinegun, you have to modify everything that once enabled the weapon to fire in fully automatic mode. The blocking bar welded in previously keeps a unmodified bolt from being inserted in the weapon, and I have to heavily modify the bolt for it to function in semi auto only.
The next item on the list is the lower, or grip area. A block is welded in place to keep the selector switch from going into the full auto notch. This is just a piece of 1/8" thick scrap metal I burned in and ground down. Nothing special, but it works.
 Here you can see that the selector is in semi auto mode, and is unable to be pushed forward into full auto.

 The selector in semi. You can see that the L shaped link cannot go any farther forward as it is blocked by the welded in metal.

Next, I put the trigger group back in.
Before I put the group back in, I ground the right hand side sear off, so it would no longer control the bolt movement. When I modified the bolts to semi (More on that in another post), I welded up the old sear trip areas, so even IF an unmodified lower were put in the gun (which it can't, more on that in a second), it would be useless as there are no sear surfaces left on the bolt.
 If you look closely, you can see the sear tab on the right side is missing altogether. The left sear tab remains, as that is how the striker will be controlled.

After these modifications were complete, I narrowed the notch at the front of the lower, and welded up the slot in the receiver to match. This way, the slot that the lower's front tab rests in cannot accept a full auto, unmodified lower. It can only accept my highly modified lower.
To top this off, I will also weld up the hole in the receiver where the right side sear hole is. This should show anyone who is paying attention that I have no intentions of ever converting this gun to fire fully automatic.

Next up is the bolt modifications and striker, but that will be the topic of another post.

I hope this, and all of my other building posts, are educational and fun, and inspire some of you out there to build your own legal Uzi carbine or pistol.