Posted on Leave a comment

Frankengun II

Had a customer bring in another cobbled together rifle. Supposedly built and used by a friend who later sold it to the customer. His first “Red Flag” should have been when the “friend” sold him the rifle without the bolt carrier group. Apparently the gold colored bolt carrier group was more important to the friend than to my customer.

Yes, those are red anodized parts that you see. The customer initially wanted me to find a red bolt carrier group to match those parts. While there are red bolt carriers on the market they are intended for “gamer” guns looking to have the least amount reciprocating mass in order to reduce recoil. Unfortunately this makes the rifle very ammunition sensitive. The use of an adjustable gas block is almost mandatory to keep the gun from self-destructing in short order. All of these factors combine to make the gun less than 100% reliable when it starts to get dirty. Since the customer was considering this rifle for self-defense, and training for duty use, he accepted my recommendation for a standard bolt carrier group.

As you can tell from the above images it did not take long for the problems with this build to become evident. The stock is clocked about 10-15 degrees.

The gold line is the lip of the receiver extension. (AKA buffer tube) It should be to the left of the buffer retainer. This style extension uses that lip and the buffer retainer to keep from unscrewing from the receiver, if installed correctly.

Here you can see a several issues. First is the lack of staking to hold the castle nut in place. Since the aluminum endplate would not have staked well it’s better that they didn’t try. Because the gold color of the buffer tube can be seen through the staking slot it tells me a few things. One that the slot goes all the way through, which means that any staking would not be supported. The slot should be cut at an angle and be only 1/2 -1/3 the depth of the castle nut. Second is that there is nothing between the aluminum tube and the steel castle nut. So this rifle would be susceptible to galvanic corrosion. Think of it as being “rust welded” together. Without any sort of lubrication for the castle nut, the torque reading would also be suspect, if they used a torque wrench at all.

Hard to tell from this view, but this endplate not only has a QD socket it has loops on both sides for clip on sling attachment. It does not look like it was used with a sling very much since it still looks nice. The steel attachment hardware most slings use would have really chewed this up quickly.

Staying with lower receiver. The legs of the hammer spring are under the pin for the trigger and are digging into the floor of the fire control group pocket. The trigger pin has slots cut into it just for the hammer spring legs. That’s what hold the trigger pin from walking out of the receiver.

Speaking of pins walking out. This build unnecessarily used “anti-walk” pins with a standard mil-spec trigger. The brilliance of the standard trigger and pins is that it can be disassembled in the field without tools should it be necessary. Popped primers can end up in the weirdest places. This rifle will need a very small, and easily lost, allen wrench to remove.

This is personal preference, but I would have put long serrations on the top if possible. It was not very comfortable to actuate the safety configured this way.

That’s the end of the issues that were found with the lower. The magazine latch was one turn out from optimum, but that’s an easy fix. All of the issues with this rifle were found upon initial check-in, it never made it to the bench for a more in depth inspection.

The upper receiver had issues of it’s own. Let’s take a look at those.

While this is a good linear compensator, it doesn’t have much room around it. That will be an issue with some of the following pictures. This handguard is one of the few on the market that is over 16 inches long, so it covers the wrench flats over this muzzle device.

It’s hard to see but gas block is pressed up against the inside of the handguard. That defeats the purpose of the handguard being free-floating.

While the gas block may be rotated on the barrel. It’s more like that the handguard moved against the gas block and possibly the gas tube. I could not find any sort of anti-rotation feature on this handguard.

Another view of the tilt in the handguard and the rather unusual placement of the off-set foldable rear sight. I assume the builder kept what ever optic was on here along with the BCG. But I can’t figure out why it was placed in such a way as to partially block the ejection port and it’s door.

Now most of the above problems would be easy to fix if I could get the handguard off. That’s where the real problems start.

These are close ups of the screws used to attach the panels using the built in M-lok slots. That in and of itself would not be a problem if I could be certain that they were torqued properly. Since this is a metal handguard and they used metal accessories the screws should only be torqued to 35 in-lbs. The screws in the last 3 pictures are not square leading me to think that they have been severely over torqued. In one of the pictures there is evidence of an accessory having been over torqued and then removed. Others show that the picatinny rail has not been installed flat to the handguard. Because of the possibility of these screws not coming out easily, I built some extra time into my estimate.

Some of these sockets are badly damaged, making the removal of an over torqued fastener even harder.

Having found these issue just by looking the rifle at the dining room table I knew that the entire rifle would have to be completely stripped down and rebuilt to ensure that all the proper assembly procedures were followed. That would be the only way to make sure that things like the barrel nut and gas block screws were torqued correctly. Most of the time I could just remove the handguard with the accessories attached, but remember how little room there was between the muzzle device and the handguard. Just remove the muzzle devise first then right, no go. The handguard is 16.5″ long and so is the barrel. That means I can’t get to the wrench flats. Because of the recipe of parts that were used I would have to peel all the layers off like an onion.

There were issues with the design of the handguard. The M-lok slots on the bottom were unsupported, because of the overly long ventilation cuts on either side of them. I found one of the slots showing evidence of bending, most likely from having had a vertical foregrip installed at one time.

I did an estimate for the work including new handguard, bolt carrier group, endplate and other parts to get it up to a standard that I would feel comfortable with letting it leave my shop. After doing the math, it was almost the same price as if I were to build him a brand new upper with all new parts, and make the few changes to the lower.

Unfortunately the customer had not budgeted for this, and chose to pick up his rifle with out any work being performed. I do not have any after pictures or performance improvements to show you for this project.

So buyer beware, if that rifle seems to good to be true, get it checked out by someone. Hopefully this article, and the other Franken Gun article, give you some useful information to evaluate that used AR you have your eye on.

Posted on Leave a comment

The “Frankengun.”

This is an AR pistol that a customer picked up at a gun show. He brought it to me to look over and address any issues that it may have. While it may look fine at first glance, I would not be doing this article if it was.

The first thing that I noticed was that the castle nut was not staked. While it is not absolutely necessary to stake the castle nut, it costs nothing and doesn’t take long to do. If the person doing the assembly doesn’t care to take the time to do this simple step what else did they skip?

Well apparently using a proper 3/4″ inch wrench to attach the flash hider was just too much. Not exactly sure what they used. Pliers of some sort is my guess. Channel locks or locking pliers most likely.

For those of you not familiar with this platform, the gas tube should NOT go down towards the barrel.

No clearance for the gas tube. Not a problem for the person doing the initial assembly, just use a rabid beaver to chew a hole in the handguard.

What goes down must go up……………….eventually. There are supposed to some bends in a gas tube. This is NOT one of them.

These are what I was able to find by just doing a quick inspection on the outside. It didn’t get any better once I opened it up.

By the looks of the buffer, that beaver was not full after chewing on the handguard. These marks are the result of the buffer hitting the retainer during firing. The buffer should only touch the retainer when the upper and bolt carrier are not in place. The bolt carrier should push the buffer off of the retainer when closed. There are a couple of ways to check for that this. With both the takedown and pivot pin pulled out the upper should be pushed away from the lower by the buffer. Another way is to remove the charging handle, replace the bolt carrier, close the upper and you should be able to see the buffer move. I tried both of these tests and it passed. So here is another short cut taken by the builder. They took a chewed up buffer that they didn’t want and put it in a gun that they were getting rid of. Are you starting to notice a trend that started with the lack of staking on the castle nut.

This is the back of the bolt carrier. There doesn’t appear to be any obvious burrs or deformations that would cause the marks seen on the buffer.

Staying with the bolt carrier, I checked the screws holding the gas key on using the reverse torque test. Proper forward torque should be approximately 55 in-lbs. The reverse test starts at 25 in-lbs. One of the screws came loose at that range. The next step is 35 in-lbs. The other one failed here. The staking here was also almost nonexistent. If your gun shows signs of being undergassed, and you see carbon built up at the front edge of the gas key then have it checked out.

You can see by the shiny spots that this gas key was starting to move on the carrier. There’s a little carbon built up around the gas port but it has not made it to the sides of the key, so there were no outward signs that this was coming lose. This issue was caught before it became a real problem. Lose screws have a way of becoming broken screws.

Results of the first few passes on a diamond plate to “deck” the gas key. If I had just simply tightened the screws back down it may have still leaked in the future.

Finished “decking” the gas key. We are limited to fixing only this piece because of the way the carrier is machined. I use a bearing retaining compound to fill in any remaining imperfections in the mating surfaces.

These pictures show the retaining compound squishing out, and the new “OCKS” used to secure the gas key. (Optimized Carrier Key Screw from Michiguns Ltd. http://www.m-guns.com)

Using a MOACKS Plain also from Michiguns Ltd. to properly stake the gas key screws.

(Mother Of All Carrier Key Stakers)

The OCKS give a place for the metal that is displaced by the staking a place to go and keep the screws secure. The burrs that caught the fibers from the rag were eventually removed.

Original extractor spring and insert. Since there were other suspect parts in this gun it just made sense from a reliability standpoint to replace it.

In the image to the right the original extractor spring and insert is on the right, the Sprinco 4-Coil spring and insert are on the left. https://www.sprinco.com/

Next I checked the gas rings, they seemed fine and were reinstalled

This is the ejector after polishing. Didn’t take a before picture, but it had a pronounced projection from the machining. It would have eventually scraped brass from the bottom of the case. That could have ended up down the bore that the ejector is in causing poor performance or even a malfunction if the case is not pushed clear of port fast enough.

Original ejector spring on the right, new on the left. The original may have been fine, but for few dollars a new one cost, it was better to replace it. With the ejector and spring out I checked the headspace and it passed.

The next check I performed was to see if it actually has a 5.56 NATO chamber and throat. This gauge from Michiguns Ltd.checks for that.

To start I “Sharpied” the end, to show if there was any interference.

The gauge is then pushed lightly into the chamber. It should fall out if the throat is the proper size. Go figure it got stuck in this one.

The white line in the ink is where the gauge made contact with the throat. This barrel did pass the “plunk” test with some factory ammunition so I didn’t try to fix this.

If you look at the feed ramps in these photos you will see that the center locking lug protrudes into the feed ramps cut into the upper receiver. This can cause malfunctions by catching either the bullet tip or the edge of the case as it’s trying to feed into the chamber. There are also some machining marks still visible.

The major work on the right side is done, and the left is almost done.

Here the ramps are all finished. Nothing to snag on.

Judging by the carbon ring it appears that the gas block was slightly misaligned.

The barrel is not dimpled so there was no place for the set screws to index in.

Using a jig I added a dimple. The picture is before I reblued the surface.

New gas block and tube installed.

New gas tube on top. Original on the bottom. Muzzle end would be on the left.

Closer look at the chewed up flash suppressor. In this image you can see that the crush washer has been installed backwards. The muzzle device was not tightened to specs either.

This is why I couldn’t see the crush washer with the handguard installed. Speaking of the handguard. The following images may be disturbing, if you care about how your firearm is assembled.

This is the bottom of the handguard. Not really sure why they went after this area. Probably the mildest definition of a mistake. It gets worse from here.

You were warned.

After looking at this closer. It appears that this handguard is for a blowback operated platform since it doesn’t have channel for a gas tube. That didn’t deter someone from making one. Not sure how long it took to make this disaster, but it had to go. Now that the upper and barrel are fully disassembled it is time to start bring this thing back to life.

The gas block was previously installed. Here is the new Midwest Industries Pistol Blast Diverter.

https://www.midwestindustriesinc.com/MI-AR-15-Blast-Diverter-5-56-2-23-p/mi-pbd.htm

Installing the new handguard. A Midwest Industries 10.5″ Slim Line Handguard.

https://www.midwestindustriesinc.com/MI-SLH10-5-p/mi-slh10.5.htm

Back up Iron sights reinstalled.

Completed upper with Holosun Red Dot installed. This is much better.

Next was to address the lower receiver. For the most part there were no major issues found. Just the buffer and the non-staked castle nut.

The roll pin for the trigger guard was a little above the surface of the ears. That was a quick fix.

The hammer and trigger springs were okay, so they were reinstalled.

Added a set screw for the take down pin retaining spring and detent. This will keep the spring from coming out unexpectedly, should the endplate be removed.

Torqueing the castle nut to 40 ft=lbs.

Castle nut staked in 2 places, as per the manual.

Here’s the completed rifle getting a final cleaning before being returned.

Added a Blue Force Gear Sling and Midwest Industries Swivels.

Business end of the Blast Diverter.

Streamlight Pro-Tac Rail Mount HL-X with Laser. 1000 Lumen light with built in laser.

https://www.streamlight.com/products/detail/index/protac-rail-mount-hl-x-laser

The finished product. Short, light, reliable, what else could you ask for.

Posted on Leave a comment

First Customer Build: The Upper

Back for the second half of the build.

The stripped upper on a bench block preparing to install the forward assist.

Completed upper with the tags for the parts used. The customer is left handed and may run the charging handle from the right side. In that case the use of the FCD Low Drag Forward Assist means less chance of scraped knuckles during a malfunction clearance drill.

A view showing how minimalist this forward assist is.

Before and after of the feed ramps on the Criterion Barrel.

Initial dry fit of the barrel to the receiver. Went back and opened up the right edge of the right ramp. The left ramp was okay. Don’t really want to take the anodizing off the ramps in the receiver as that makes them prone to being damaged.

Prepping the bolt to check headspace. This fixture makes it easy to remove the pin holding in the ejector. The ejector can give a false feel during the headspace check.

Stipped bolt ready to check headspace.

My headspace gauges are on the bottom of the picture. Since this picture I have added a proper 5.56mm headspace gauge. The barrel did pass the .223 Remington GO gauge. It also passed by not closing on the 5.56mm max gauge.

Nicely dimpled by Criterion

SLR Jig to add a second dimple. Why? Because your gas block can’t be too secure.

After the jig.

Cold blued he spot for appearance and corrosion protection.

Used Loctite 620 Bearing Retainer to bed the barrel to the receiver. The bearing retainer will swell slightly, filling any excess space, and lock the the two together improving the rifles consistancy.

Barrel and receiver hand tight. Waiting for the bearing retainer to set up.

Gas Block

Installing the Sionics Mid-Length gas tube.

Just enough of a second dimple for the set screw to dig into.

Original set screw.

The knurled set screw I actually used. In addition to the knurling I also used VC-3 to insure the screws don’t loosen.

Torquing the barrel nut on the Midwest Industries Slim Line Combat Rail to 40 foot-pounds. This is the 15 inch version. I really like that the barrel nut for this line of handguards doesn’t need to be timed to the gas tube.

Torquing gas block set screws to 30 inch-pounds.

Fully assembled gas system.

Testing that the BCG not impeded by the gas tube. It passed with no interference from the gas tube. This will maximize gas tube and gas key life.

Customers choice for a muzzle device.

Hand tight to the crush washer.

Tightened till the marks aligned.

Almost finished. Most of the hard stuff is on.

Even though its probably not needed. I still used the rail alignment fixture to make sure the rails are straight.

Torque tab installed. Keeps the handguard from coming off and prevents over-tightening of the screws.

Setting the torque.

Following instructions.

Assembly complete. only a few more parts to add.

Starting top see what the final product will look like.

This is one of the last parts.

First assembly. Hope the customer likes it. Just have to add a few accessories.

Its not loaded. Just waiting on BUIS from Midwest Industries.

Posted on Leave a comment

First Customer Build: The Lower.

This is how a build starts, with just a stripped receiver. For this build I will be using a receiver with my company engraved on it.

Started with the Low profile Magazine Catch from Forward Controls Design (FCD).

Paired it with a Enhanced Magazine Release also from FCD.

More FCD parts. This time their Augmented Bolt Catch/Release. The pads are a little bit bigger and slightly angled to manipulation more positive.

Next up were the take down and pivot pins. These pins from FCD are .040 longer than normal and made of better steel. It may not seem like much, but that extra length is appreciated when all you have are your knuckles to knock those pins through.

Here you can see the set screw used to capture the spring for the take down pin and the VC-3 from Vibratite. The screw keeps the spring from getting launched into the great beyond, should the customer chose to change the end plate and not realize there is a spring there. The VC-3 is used to keep the receiver extension from possibly rotating during castle nut torquing, or during hard use. It’s not as “rigid” a connection as Locktite type products would be, in that you can still adjust the parts after it has set up.

The receiver extension ready to be installed. I used a castle nut from FCD, which has more and deeper notches allowing for more secure staking. Grease is used in order to get the proper torque value and to prevent galling between the dissimilar metals. The end plate is from Midwest Industries and has a QD socket in it. I like to include this version in my builds so that the option to attach a sling at the rear of the receiver is already there.

Just waiting for the VC-3 to set up overnight, and the packaging for the parts.

Receiver Extension fixture used to torque the castle nut.

Mark from spring loaded center punch.

First stake finished.

Start of the second stake.

Second stake finished, as per the manual. Don’t have to worry if this will come apart under hard use.

Bravo Company Manufacturing (BCM) Trigger Guard. The button head screw for the front is an idea I got from a builder page on Facebook. I think it looks good enough to make it a standard for polymer trigger guards.

Checking the springs on the ALG Defense QMS Trigger.

Trigger and disconnector installed. The grease is on the sear surface. You may also notice how the bolt catch tilts away from the receiver a bit more than normal.

A lot of work since the last picture. Forgot to take pictures a long the way. The hammer has been installed and being tested against the block. For parts longevity avoid dropping the hammer without some sort of cushion. If you let the hammer fall full force against the receiver wall or the bolt catch it can damage them over time. You can use your thumb, foam ear plug, or a purpose built block like I have here, just slow the hammer down some how. This only applies when bolt carrier group is not there to take the blow. Such as this picture when both halves are not attached or when the receivers are “shotguned”. Most AR rifles should not be damaged by dry firing in an assembled condition, like used for reinforcing marksmanship fundamentals.

The pistol grip is also from BCM it is the MOD 0 version since the end user has small hands. This will manipulating the controls a little easier.

The safety you see here is not the permanent one its just a place holder until the ambidextrous one comes in.

After the addition of the Magpul CTR stock the lower is finished. I will cover the build up of the upper receiver in another post.

Posted on Leave a comment

Worked on an AK

This is what it looked like when I started. Pretty simple, had a few internal upgrades and an aftermarket muzzle-brake.

The customer wanted me to add a side mount for a scope.

Had to break out the power tools to modify some screws to make it work.

The middle is the original, right is from the store, left is filed down to fit the holes in the mount.

Mount finished. Didn’t use the middle hole because of interference with internal parts.

Added a Magpul AKM forend.

Added a Magpul Stock

Here’s the finished rifle with red-dot and sling. QD sockets, sling and cheek riser are on back-order. Much like most projects it;s a work in progress.

Posted on Leave a comment

Testing

This is a “Liberty Training Rifle” I set up for my wife to use for an AppleseedProject.com shoot. It’s a standard Ruger 10/22 that’s had a few modifications done to it.

First thing I changed was the sights. It now has “Tech Sights”. Giving it a longer sight radius, along with having a sight picture very similar to an AR style rifle. These sights also adjust in a way that is more predictable, than using a hammer on the factory sights. Here’s the link: https://www.tech-sights.com/

Next up was the stock. The one I chose was the RM4 by Adaptive Tactical. This stock allows for the length of pull to be easily adjusted and has a pistol grip that feels similar to an AR. The “Muddy Girl” camo pattern also helps it stand apart from the other rifles on the line. Here’s the link: https://adaptivetactical.com/

There have been some internal changes made to make the rifle easier to use. The bolt lock has been modified, allowing it to be released with just a slight pull. Additionally the magazine release has been changed to a paddle style, for easier and faster magazine changes. The extractor has been upgraded, with one from Power Custom (http://powercustom.com/) for reliability. A jig was used to add a hole at the rear of the receiver, allowing the barrel to be cleaned from the chamber end without the need for removal. So far there has been no trigger work.

Other accessories added, are a cuff style sling and 10 round stick style magazines.

She used Armageddon Gear (https://www.armageddongear.com/) items to eliminate shooter input from influencing group size. I am also an Armageddon Dealer if you are interested in what you see here.

The Dillon Precision (https://www.dillonprecision.com/) shooting mat came in handy since the range was damp from the frost coming out of the ground and snow melting.

Well that’s the background info, here’s the meat of the story.

Since you can’t reload for .22 rimfire the only way to shoot small groups is to test what that firearm likes. First up were some CCI Stingers. This rifle definitely did not like those. I think the bolt velocity was too high, in that the bolt is hitting the rear of the receiver before the bullet leaves the muzzle opening up the group size. Not good for what she wants to do with this rifle.

We moved on to trying different loads from Winchester. One was a 36 grain hollow point that comes in a 555 round bulk box. This was much better than the Stingers, it actually grouped. This is rated as a high velocity round instead of Hyper Velocity like the Stingers. I would say the groups were fair, but still workable for training.

Next up was Winchester Super X 40 Grain round nose. These grouped really well in her rifle (and mine as well). If she had to shoot an AQT (Appleseed Qualification Test) right now this is what she would use.

Lastly we tried some Federal ammo. It too grouped fair, similar to the first Winchester’s we tried. These were the last groups for this day. She didn’t think that this was a good representation of what this ammo could do since her concentration was starting to go. We decided that she should retest this one next time.

This is not a reflection of the quality of the ammunition we tried. This is just what we observed with this particular rifle, on one day, with the ammunition we already had.