If you do any AR building, you know how it is when you have spare parts. Anything can be the impetus to do a new build. I mean, if I have a spare grip, I may as well build another rifle right? Well, this time I actually had a spare lower, so I definitely had to do something with that. Since I ended up with a Bad Attitude Department lower and a complete KAK Industry WW III upper, I’m calling this one the BAD KAK WW III build.

A Bad Attitude to Start With

I’ve ordered a number of custom lowers from Bad Attitude Department. When I got my XCOM lower for my sci-fi build I ended up getting two lowers. I got those in the raw and ended up moly coating them. I did one in FDE for the main XCOM X-9 build, and did the other in SOCOM black for some later project. I kept stumbling across the black lower in my parts bin as I was doing other work, and decided to see what I could put together.

I had a lower parts kit from B. King Firearms, a spare buffer tube that I think was a take off from a PSA lower and a KAK enhanced buffer and flat coil spring that I had been waiting to use on a project. I have a bunch of spare grips, but the cool carbon fiber fiber finish A2 Echo grip from MEAN Arms seemed like a good fit for this one. Initially I had a CAR stock on the build left over from a retro build. I swapped that out to a regular M4 stock later, since this was going to be a more modern build.

Where To Buy

bad attitude custom lower

The KAK WW III Upper

When it came to the upper half of the rifle, I was a little more pressed for parts. Everything I had was set up for either SBRs or pistols. Since I didn’t plan on SBR’ing or bracing this build, I started looking around for what kind of carbine configuration I wanted to do. Since I’m a fan of light and short builds, even if they aren’t SBRs, I was looking in that direction. As luck would have it, right around the time I was checking out my options, I got an email from KAK Industry with a sale on what they were calling their WW III Midlength Lightweight upper.

KAK’s WW III offerings usually have pretty good discounts, as they tend to be built from things they have an excess of stock on. That works for me, as they’re all first quality parts. So as long as there’s a configuration you like, it’s a win-win. You get a good deal, and they get to move something they have an abundance of.

Now, I generally tend to put together my own uppers. I don’t have anything against factory builds, but I like building, and can usually pick exactly what parts I want if I do it myself. I didn’t have an exact plan in mind for this build though, and the WW III checked off the boxes I was looking for.

The WW III used a KAK flattop upper with forward assist and brass deflector. It was fitted with a 5.56mm 14.5-inch government profile barrel that was a contract overrun from, you guessed it, the U.S. government. KAK had one of their new HK flash hiders pinned and welded on to bring it to 16 inches, so no worries on barrel length. Not having to take it and get it pinned and welded myself saved some cash too. KAK used a midlength gas system, which I’m a fan of. It used a 9.8-inch M-LOK KAK rail. I typically go with longer rails, but the price was right on the upper, and it was a little different than my other builds. It shaves off some weight too, which isn’t a bad thing. The sale price was just $225. I added in a KAK Bolt Carrier group and with the pin and weld option my total was $$305.

Since I was ordering the upper and bolt carrier group anyway, I added a KAK extended charging handle as well. Their Big Latch charging handles are my favorite, and I’ve used them on a fair number of builds now. They aren’t fancy, basically a GI charging handle with an extended latch, but they work for me. There’s enough of an extension to make charging easy, even with optics mounted, but not so much as to hang up on anything. It’s a clean, simple design. They’re also quite affordable at only $24, which is why I have a bunch of them.

I felt like calling this one a build was a stretch since, when my KAK parts arrived, I simply slapped the upper on my lower, popped the charging handle and BCG in, and was done. Since the WW III top half is all KAK, and the lower is from Bad Attitude Department, I’m calling it the BAD KAK WW III build.

Where To Buy

kak industry complete upper

The BAD KAK WW IIII

So, for an easy build that started with some spare parts and ended with grabbing an on sale upper, I’m pretty happy with the results. The gun looks clean to my eye, and handles great. It’s light at only 5.15 pounds, about like an M1 carbine. That’s about perfect as far as I’m concerned. 

I had just gotten one of the new Swamp Fox Raider prism sights around the time of the build and decided to check it out on the KAK rifle. I wasn’t planning on running irons on this build anyway, so the prism sight is a good choice. Even if the battery dies (unlikely with a 35,000 hour runtime and a shake awake feature) and you lose the illumination, you still have the etched reticle to shoot with. Adding the Raider bumped my weight up to 6.10 pounds which was still pretty good. 

I have a ton of AR mags. GI surplus, Brownells aluminum, various generations of Magpul and a few other odds and ends. I have been working with Amend2 mags over the summer though and have had very good results with them so I snagged their translucent Mod C mag to use with the build. I know Magpul just released their T Mag, and I’ll get some to mess with eventually, but I had the Amend2 already and knew it worked. I had a couple black Mod 3 Amend2 mags as well that I set aside for use with the WW III.

Range Time

Taking the WW III to the range was uneventful, just how I like it. The KAK upper ran everything I put through it without issue. Being that I’ve used a lot of KAK parts in my previous builds, I wasn’t surprised, even though I hadn’t used one of their complete uppers before. 

The Swamp Fox Raider worked out well. I had previously tested it on an SBR and was pleased with it. The glass was clear, and the reticle showed crisply. It was quite usable even without the illumination on. With the red reticle turned on it made picking up the sight fast, and there was plenty of adjustment to make it visible even in bright sunlight. I had been shooting steel at 300 yards with the SBR and the Swamp Fox, which impressed me since I don’t do a lot of longer range shooting. I figured if it did that with a 12.5-inch barrel then it should be at least as good with KAK’s 14.5-inch tube. 

I sighted in with 62-grain Fiocchi Range Dynamics .223 loads, and used those Winchester Target & Practice 62-grain FMJ for my initial break-in and some of my typical plinking. After confirming my POA, I stepped out the 300-yard gong again with Hornady Frontier 75-grain BTHPs and PPU Matchline .223 75-grain HP BT loads. As I suspected, I was able to consistently ding the gong with little effort. I could have benched it and shot some groups, but as any of you who’ve read my other pieces probably know, I only do that when pressured by my editor. Steel and dynamic targets are much more fun.

The WW III is quick to shoulder. The light weight and compact overall length made transitioning between targets fast and smooth. It’s a pleasant rifle to shoot. Despite the lighter weight, the heavy KAK buffer and midlength gas system made it a smooth shooter. Not that 5.56mm is a thumper by any means, but some builds do shoot flatter than others. 

The Flektarn Connection

I was fairly happy with my grip and stock set up, but then I saw the limited drop of German Flektarn camo pattern stocks from B5 Systems. Since my XCOM lower had pseudo German markings I figured Flektarn would be a perfect fit. I fooled around and missed the initial drop and was kicking myself, but recently found a set from Shooters Choice in South Carolina. They even had a good price on it and pretty fast shipping. They still had some listed at least of this writing, too.

I picked up a Flektarn pattern sling from Edgar Sherman Design off of Ebay along with a surplus German HK spring clip for the front of the sling. The B5 set consisted of a Bravo stock, Type 23 grip and a vertical foregrip. B5’s stuff is always solid. It made for a unique but practical upgrade for the build.

Round Up

For a build that started off as a hodgepodge of what’s in my parts bin, the KAK-centric WW III build turned out pretty well. It’s a simple, clean carbine. The lightweight and slim profile make it handle great. Reliability was perfect, and accuracy was quite acceptable for anything I’ll be doing, which is mostly plinking. I have a couple “serious” rifles if I ever really need one, so most of my builds are just for fun, and the BAD KAK WW III definitely checks the fun box. 

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15 COMMENTS

  1. I hope to build an AR pattern rifle some day.

    The real question that is eating at me is what caliber. Do I go with an AR-15 design chambered in 5.56x45mm NATO? Or some other cartridge (e.g. .300 AAC Blackout or 6.5mm Grendel)? Or do I make an AR-10 design? And then do I chamber it in .308 Winchester or .243 Winchester?

    • I love my .243. But it is a bolt gun with a low round count annually. A lot of references say that the .243 will wear out a barrel about every 2 thousand rounds.

      If I was doing an AR10 it would be in .308.

    • .243 Win LR308s absolutely rock. Have one and love it. Bit chunky though if I spend a few hundro it wouldn’t be to build another rifle but to put this one on a diet!

      For the barrel do yourself a favor, 22 or 24″ 1:7 or 1:8 twist with Rifle+3 gas and fluting. That’s what my next one will be.

    • Make it a 5.56mm. It’s the most common caliber by 1000x. It’s also the least expensive ammo by 3x or more. Mags are the cheapest in 5.56 and are everywhere. The last thing you want in a SHTF situation is a pistol chambered in 8mm Nambu and an AR15 in ANY caliber other than 5.56.

      • Slapshot,

        The last thing you want in a SHTF situation is a pistol chambered in 8mm Nambu …”

        I may actually want my pistol chambered in 8mm Nambu if I am in Japan!

    • grasshopper forget complicating matters with other calibers, your first AR should be a 5.56. The AR-308 can be a costly, finicky beast as many newbes have discovered.

      Begin with a stripped Aero lower and their stripped M4E1 upper. Or use the easier to assemble retail packaged AndersonManufacturingdotcom closed lower receiver with the Aero M4E1 stripped upper.

      Stock assemblies for a first timer should be the easier to install and reliable cycling A1 or A2 rifle length like those from Fulton Armory. First build IMO should be a Carbine with a barrel from Criterion or the FN 20-100046 M4 currently on sale for $207 at Optics Planet. BCG should be on the level of a nitrite Angstadt, etc. If you are intending to use iron sights keep it in mind front iron sights on a float handguard are usually off so it’s either a barrel gas block attached front sight which for a 16″ Carbine barrel gas port requires a 7 1/4″ length float hand guard or use the more stable Aero Enhanced M4E1 upper receiver and their stable float hand guards that covers the gas block.

      • Debbie W.,

        I have heard from multiple sources that building an AR-10 can be difficult (in the finicky sense as you aptly described it).

  2. I’ve no idea who owned this 03A3 before I got it but they must have never cleaned it. Mercy the barrel was copper fouled.

    • LoL 😂

      I’ve done that, come across some parts while looking for something else then end up building a rifle around those parts.

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