5.56 Timeline

The USAF take-down GAU-5A survival gun

Picture from USA Military Channel https://www.youtube.com/watch?v=k9ENCaRlYOM

Not that long ago, the Air Force adopted a new break down rifle for the survival kit of pilots. They decided to recycle the designation GAU-5A for this new weapon configuration.

The original GAU-5A was the Colt Model 610. Here is a picture from RetroBlackRifle.com

Many of old carbines were later rebuilt into other configurations, the GAU-5A/A, GAU-5A/B, GAU-5B/A, GAU-5P, GUU-5P, etc. There is a fair chance there are a few of these floating around in their original configuration, and others have likely been rebuilt into M4 carbines.

But this isn’t about that cool old gun.

The new GAU-5A is a retrofit to a standard M4. This break down setup was picked because they could jam it in their current survival kit along with four full thirty round magazines.

To make the lower smaller, they remove the sling loop from the M4 stock, and install a FAB Defense folding pistol grip. Part number AGF-43S. I looked around for price and most places had it out of stock. $43.99 was the price I found for a black one, 36.49 for other colors.

This break down rifle uses a shorter barrel. From what I can find, it is reported that a Bravo Company 12.5″ barrel is being used. I’m guessing the model at this page: https://www.bravocompanyusa.com/BCM-Standard-12-5-Carbine-Barrel-Stripped-NFA-p/bcm-brl-s-12%20std.htm Flash hider appears to be a standard A2. The stripped barrel is for sale for $239. You would still need a low profile gas block, flash hider, and crush washer.

A low profile gas block is used, and for the take down system a custom different length gas tube is used. That is provided with the take down kit.

The take down kit is a retrofit for standard AR15 uppers and barrels. It is made by Cry Havoc Tactical. This “QRP Kit” sells for $349 shipped. They also make a model for .308 ARs. This kit lets you use most standard aftermarket free float hand guards. Link here: http://cryhavoctac.com/qrb-kit.html

The chosen hand guard is a 10.5 inch long Midwest Industries “MI-G3ML10-BLK”. Due to the quick change barrel kit, this hand guard is pushed out longer than if it was mounted normally. It runs $169 dollars from MidWest Industries website. https://www.midwestindustriesinc.com/product-p/mi-g3ml10-blk.htm

For sights, this little survival carbine uses the Magpul MBUS PRO LR. It appears to be using the version adjustable for distance. This would let the shooter roughly adjust from 200-600 meters. To buy a new set would run you about $200 dollars.

With the exception of a full auto lower, if a person wanted to make a “clone” of one of these guns, all the parts would be easy to source and readily available.

When this weapon was first announced, I recall the gun forums and the like generally responded negatively to the announcement of this weapon. All sorts of alternatives were suggested, most of them ridiculous.

This new gun is an interesting oddity. But I don’t imagine it will get much of a fan following. I doubt it will ever be considered classic like the original GAU-5A.

My AK, an Arsenal SLR106FR

I posted a picture of my rifle the other day, and someone asked for more information, so here it is:

Given the choice between the AK or the AR I would take the AR every time. But as a gun nut, I would very much love to over every gun out there. Ever one. But having limited money and space I have to be selective with what I buy. Yet, for me, I find owning an AK worth while. Not only is it fun and an iconic weapon, the AK family of weapons is so very common in the world I feel it is well worth keeping a level of proficiency with it. So I like having one to training and plink with.

While 7.62×39 and 5.45×39 are good cartridges, I decided to buy one in 5.56×45, so I can use the ammo I already stockpile for my AR15s.

There are a handful of options in 5.56 AKs. Since I purchased mine, there have been a couple newer rifles to the market. If you talk to the hard core AK nuts their views on the 5.56 AKs are very diverse. I went with an Arsenal SLR106FR. Some would say it is the best 5.56 AK, others would say it is the worst. I choose it because it is one of more common options and the Circle 10 mags tend to be excellent.

When I purchased mine, there were a large number of SLR106F models for sale cheap. The F model is the full sized rifle, but no size optics rail. I found the model I wanted for sale (at a honestly overpriced price) from gomoose02 on Gunbroker. Gomoose02 aka Brothers Firearms Shop misrepresented the rifle I received and charged over MSRP because of their false claims. Like I dummy, I fell for it. But despite this, the rifle has worked out ok for me. Of all my dealings on Gunbroker, only twice were there major issues, and in both times the seller outright lied on their ads and in their communications.

How was this resolved? Never was, I got leave bad feedback for them, and in return they leave bad feedback for me. When you buy from Gunbroker, you pretty much have to accept that if the seller screws you, Gunbroker will do nothing. They have to screw a whole bunch of people before Gunbroker will consider banning them.

Anyways, back to the rifle.

The model I purchased came from the factory with a quad rail. Out of the box it came with a 5 round mag. In the photo below, I threw in an old Trijicon Reflex. gomoose02 was kind enough to throw in another mag. IIRC it was a promag. It was a mag designed for a different AK, and someone hacked it up to fit in the SLR106. It would malfunction every time I tried to use it. I threw it out.

Once I got some Bulgarian Circle 10 5.56 mags, the rifle functioned well.

Like the majorities of AK rifles I have used, this has crooked sights. An adjustment for windage had to be made on the front sight.

One of my favorite things about the SLR106FR is the ability to fold the stock. The AK100 style folding stock locks up like the proverbial bank vault. When it is open it is just like having a fixed stock. Then you can easily fold it by pressing the button on the left rear of the receiver to make the weapon more compact.

In use, the 16 inch barreled AK is similar length to a 16 inch barreled AR15. It is longer if you are using one of the more modern muzzle devices like the muzzle break it comes with.

But as I said, it is nice to be able to fold that stock for storage and transportation.

The Magna-Matic AKFST sight tool is a little pricey compared to other options, but it is better than those other alternatives.

Often with guns I am a little torn between leaving them stock, or heavily customizing them. Part of me would love to order a Zenitco quad rail, railed top cover, etc. But I keep in mind that I mainly keep this gun to maintain familiarity with the standard AK rifle. Also I can’t afford that other stuff right now.

I did pick up a couple of accessories. Surefire makes a silencer mount that attaches to the 24mm Russian threads on the rifle. These always seemed to be out of stock everywhere. Then, on an almost random chance, I came across one on sale on Gunbroker. So, I now have the ability to mount my Surefire silencer on my AK.

This installs with shims between the muzzle and the mount.

My only complaint is that these three tines ring like a tuning fork when I shoot or when I bump the rifle. If Surefire ever makes a closed tine version, or better yet a Warcomp version I will spring to purchase it.

Russian muzzle threads on the AK are not exactly known for being perfect. There can be concerns about the suppressor being concentric to the bore. Fortunately I am using a .30 cal suppressor on this .223 cal rifle, pretty much eliminating any concern about baffle strikes.

Not that long ago I picked up a Russian Scope, a 1P29 Tulip. It is a cool scope, but not right for me. I’m currently trying to sell it. I tempted to just slap an ACOG on this rifle. You can read my write up on the Tulip here:

It is a fun gun. I don’t much care for the canted sights, but I can live with that. My biggest complaint would be that the Arsenal 2 stage trigger in it feels very slow to me. When I do something like practicing quickly engaging a target with multiple rounds, it feels like an eternity from when I release the trigger to when I can fire again. It might all be in my head, but it seems me that that the trigger in this gun makes it really slow for rapid fire. Someday, I might swap out this trigger for an alternative, if I do, I’ll write about it.

WTF quote of the day

This gem bought to you by AR15.com, a giant forum that sometimes talks about guns.

The 5.56 round is practically harmless unless it fragments. Reliable fragmentation velocity is about 2600 fps.
Your barrel has a muzzle velocity under 1900 fps, which means its effective range is zero meters. You could shoot someone with it point blank in the chest and they’d likely be fine, unless you happened to get lucky and strike the spinal cord. If you had used an 11″ barrel, you would probably OK for 30 yards or less…or if you had used a .300 blackout, you’d be fine with that barrel length.

AR15.com User Pebble LINK

At least the first person to respond to him responded with laughter.

Let me share a failed gun project

I can’t say exactly when I came up with the idea of this, but I recall a couple of things spurring it on.

There was a thread on a gun forum about discrete ways to move firearms to and from the range. One person was talking about packing their firearms in a bucket. They could put the ammo, paper targets, the firearm, and anything else they needed in an innocent looking bucket and head to the range. I thought that was a really cool idea. I also was enthralled with Polish mini-Beryl and the SIG 552 Commando at that time.

Polish Beryl
Polish Beryl
SIG 552 Picture from https://weaponslover.tumblr.com/post/170539763905

I started to really like the idea of a very short barreled 5.56 that had a folding stock. Back when I was doing thing, the side folding options for the AR were pretty rare and or unreliable. And pistols braces were not a thing, so it was not something that could easily be done.

So did I want?

  • A very compact 5.56 weapon system
  • A right side folding stock
  • Ability to mount optics
  • Ability to mount a silencer
  • Right side folding stock

How did I justify it?

Well, first, I wanted it. That was enough justification. As for performance out of a short barrel. All sorts of groups around the world have fielded very short barreled rifles, From the AK74SU, G36C, Mini-Beryl, etc. There are many sub 9 inch barreled 5.56 and similar weapons out there doing serious work. Are they ideal? No, but they do get the job done. I wanted something that could be small, and discretely packed away.

I looked at options. The SIG 552 was nearly unavailable, and if one could be found it was stupidly expensive. In hind sight, had I just sprung for one, I would probably still have it and it would be a cherished part of my collection.

I saw that there were 5.56 AK rifles available. I also saw that we had all sorts of new options for upgrading AKs. Railed top covers, quad rail hand guards, etc.

This AK for example has a right side folding stock, railed top cover, and other cool upgrade.
This Krinkov by Kreb’s Customs was somewhat similar to what I wanted.

I saw people were making aftermarket right side folding stocks. Why a right side stock? Because the right side is the RIGHT side. Only godless commies or euro weenies would make a stock that folds to the left.

Aftermarket right side folding stock on an AK
Aftermarket right side folding stock on an MP5

I look at the option of buying a SIG 556P, going though the SBR process, then installing a Samson quad rail and an ACE side folding stock. But I was hearing a good bit of bad reviews on the SIG 556 line.

After some thought and researched, I looked into options like it being 7.62×39 or 5.45×39. I finally settled that I would use the AK platform. I would, over time, have a Kreb’s quad rail. I’d use a Tango Down front grip, and have a light mounted on the left side. The barrel would be slightly extended and threaded for use for a silencer. I’d have something like SIG diopter sights installed. At this time it was not uncommon to have HK diopters welded to an AK. Down the road, I might add a M16 mag well and use AR mags. I also liked the idea of using a rail mount on the AK rail to add my favorite optic, the ACOG.

What could go wrong?

I picked up an Arsenal SLR106UR rifle.

I decided I’d settle for a left side folding stock, as this style folding stock is pretty great. When open, it is like having a fixed stock.

I went with the rifle, as I read all these people say you could cut down the barrel and it would just work. I wanted to have the barrel cut down a little long, and threaded for mounting a modern western silencer like my Surefire 556K.

I had a local dealer SBR it. When I chopped the barrel it didn’t run right afterwards. I ended up having to send it off to have the gas port worked on.

The Arsenal finish was especially bad. It seemed to come off when I looked at wrong.

I tried a few different front hand guards.


An Ultimak worked, but got very hot fast. It would burn my fingers.

A bought a rarer set of machined delrin hand guards. I was going to run this bottom with the Ultimak top, but I realized it would take massive amounts of fitting to get this to work, so I got rid of them with out ever using them.

Eventually I ended up using the Kreb’s quad rail I planned to get from the beginning.

I had issues with excessive windage preventing zeroing. Reliability was just not there. It looked cool and was fun to play with, but it felt heavy for the size and just not very good.

I tried different different set ups, never got anywhere near the performance I would consider acceptable.

I had even picked up two different AR15 magwells for the AK. Either would have required modifications to the receiver, but had that work been done, I would have been able to switch between using AK mags or M16 mags. Had it been working well, I would have had that modification done.

In the end, I parted out the accessories and sold the gun at a loss. Put a lot of time and effort trying to get an end result with out realizing that what I was starting with was never really going to do what I wanted.

I’m not saying a “Krinkov” style AK is bad, it just wasn’t what I wanted to begin with. It wasn’t as light or compact as I wanted. Mounting a suppressor didn’t work out. Optics mounting never worked out the way I wanted. It just kept slipping father and farther away from my initial goal.

Don’t make the mistake I did. Don’t sick money into a nebulous project with out knowing if you can get the result you want in the end.

I did learn that I like the idea of a 5.56 AK. So the only AK I own is a 5.56 AK.

Anyways, thought I’d share that gun project of mine that didn’t work out. At least I learned from it.

Or maybe not.

still folds to the wrong side

Remington Model 7188

The Remington 7188 was a variant of the M1100 pattern shotgun but produced for combat operations. Unlike the average sporting use shotgun, the 7188 was made to be full auto with a cyclic rate of 480 rounds a minute and was gas operated unlike the 11-48.

Production began around 1967 and the guns were sent to Vietnam where they were most famously used by the Navy SEALS. Several autobiographies mention the use of the 7188 and the user’s opinion on it. Like most people, it didn’t take long for the end users to stop being impressed with the amount of lead that could be slung compared to the amount of time it took to reload the shotgun once fired empty.

At least a few were fitted with the “duck bill spreader”, A type of muzzle device , or choke that dispersed the shot in a horizontal pattern rather than cone shaped from the muzzle. Reportedly the duck bill used with #4 buck was the magic combination to put a man down near instantly.

First developed specifically for use by US Navy SEALs in Vietnam, the first example of the Remington 7188, the Mk 1, appeared in 1967, and was perhaps the most destructive close combat weapon produced to that date. Developed from the Remington 1100, the Model 7188 was a fully-automatic version of that weapon, with some other modifications requested by the SEALs. Though these weapons were never large in number, the Mk 1 version was the most common of them; it had a perforated barrel shroud, extended tubular magazine, bayonet mount, and adjustable rifle sights. The Mk 2 was identical, but used a ventilated barrel rib and front bead sight of a standard shotgun. The Mk 3 was also identical to the Mk 1 but did not have the perforated barrel shroud. The Mk 4 was a Mk 3 with standard shotgun-style sights. The Mk 5 was also similar to the Mk 1, but did not have an extended magazine, and also did not have the perforated barrel shroud. The Mk 6 was identical to the Mk 5, but had standard shotgun-style sights.

While the SEALs liked the fantastic destructive power of the Model 7188 (especially with the custom loads they tended to use), they found the Model 7188 had one big problem: it was highly-sensitive to dirt and fouling, and this made it quite unsuited for general use in Vietnam. In addition, the enormous recoil of a full-auto burst (even at the low cyclic rate of the Model 7188) was difficult to control, and even with an extended magazine, the ammunition supply was thought to be too small by many SEALs. There were never more than a couple of dozen of each Mark of the Model 7188 made, and they were withdrawn from service within a few years, a weapon experiment that ultimately failed. Some were converted back to semiautomatic fire; though this essentially turned them back into Remington 1100s (albeit, with unique markings and an unusual selector lever), they were designated Model 7180s.

Mk 1

It had an extended magazine, perforated barrel shroud, bayonet mount and adjustable rifle sights. This is the most common version.

Mk 2

This was identical to the Mk 1, but had a ventilated barrel rib and front bead sights of a standard shotgun.

Mk 3

It was identical to the Mk 1, but lacked the perforated barrel shroud.

Mk 4

This was a Mk 3 with standard shotgun sights.

Mk 5

This was a Mk 1 with no perforated barrel ribs and lacked an extended magazine.

Mk 6

This was a Mk 5 with standard shotgun sights.

The shotgun has a lot of appeal to some people but the truth is it has very distinct and limited roles, even more so when in an environment like the jungles of Vietnam. Full auto shotgun even less useful. The 7188 was an interesting footnote in a time of “space age” advancement in weapons technology and theory. Of course some people never let any idea go to waste and so we see fullauto shotguns still coming out from time to time. Either way you come down on the shotgun as infantry weapon argument, I think we can all agree that a limited 8 round magazine with reload speed comparable to a Colt peacemaker is not something you would want to be stuck with if going against 20 people with AKs.