Let’s Be Brief: My Briefcase AR15

My primary firearms instructor told us: “we don’t carry pistols because they are powerful. We carry them because they are convenient.” Ever since hearing those words and reading about short barreled AK47 rifles I’ve been trying to shrink rifles down into a weight and size convenient enough for everyday carry.

My latest attempt is an AR15 chambered in .300 Blackout.

It fits in a briefcase.




I’m going to do a video review after I’ve trained with it more, but here’s the quick run-down.


All of my everyday carry (EDC) rifles are built to engage at short ranges. My definition of “short range” is 150 yards or less, with an expected range of 5 to 40 yards.

I also assume that I am on my own during a self-defense / active shooter incident, although my wife and I logged almost 20 hours of partner-based training last year. We also practice outside of class.

This AR pistol will replace my SBR Mini Draco AK47 as my EDC rifle. I wanted something that was a little lighter than the AK, which weighs in at 8.5 pounds loaded.

I started this project late last December, and wrote about my intentions about three months ago.

I also wanted something a little shorter. I have a 17″ laptop sleeve that breaks up the outline of my AK47. The top of the AK (when folded) sticks out just a little bit, and if i could build a firearm that completely fit inside of the sleeve I’d feel better about opening my bag at work.

As a very low priority goal I wanted to explore a different caliber for the She-Shepherd’s AR pistol (now an SBR) so we could shorten the barrel on her firearm as well.


Length (folded) 17″
Length (unfolded) 24″
Weight (loaded) 6 pounds, 7 ounces
Barrel length 6.75″

My .300 Blackout: Briefcase Edition weighs 6 pounds, 7 ounces. That’s a little over 20% reduction in weight from the AK. I may investigate the MAG Tactical magnesium lower and a carbon fiber tube in the future to see if I can lighten up the build even more.

The 20-round MagPul MOE magazine weighs 15.2 ounces loaded. By comparison, the AK’s 20-round metal tanker mag is 1 pound, 6.6 ounces loaded.

I carry a 30-round spare mag in my backpack, so there is some additional savings there, too.


First firing impressions

Our snow is just now melting and the outdoor range is still off limits until later this month. I’ve only function tested my build and my handloaded .300 Blackout ammunition, and so far everything is good to go. I expect even better results with my precision ammunition instead of the training-oriented M80 pulls I’ve loaded so far.

A lot of people stated that anything less than an 8.2″ barrel on a .300 Blackout would lead to reliability problems, mostly due to gas “dwell time.” My build has been 100% reliable so far, but my testing has been limited.

I only intend to shoot supersonic ammunition, so maybe that’s why I can get away with a 6.75″ barrel without any issues.

We take a basic rifle class a few times a year to build fundamentals. It’s a 350 – 500 round class (depending on the class size and how fast we shoot), and part of the class is a 3-magazine move-and-shoot drill. It’s crippled the rifles of more than one student, and I’m looking forward to testing the Briefcase AR at this class come May.


My briefcase AR15 build is 17″ folded, thanks to a 6.75″ barrel and the Law Tactical folding buffer tube adapter.


  • Palmetto State Armory stripped lower: $49.99
  • Palmetto State Armory stripped upper: $39.99
  • Palmetto State Armory ejection port cover assembly: $5.99
  • Palmetto State Armory forward assist assembly: $12.95
  • Bravo Company charging handle (Mod 3 / large): $46.95
  • AIM Surplus nickle boron bolt carrier group: $99.95
  • Joe Bob Outfitters lower parts kit: $54.95
  • MagPul MOE grip: $18.95
  • Seekins Precision pistol-length gas tube: $16.15
  • Kies adjustable gas block: $33.95
  • Ice Arms 6.75″ stainless steel barrel: $193.50
  • Midwest Industries 7″ SS Gen 1 free float tube: $149.99
  • Kaw Valley Precision linear compensator: $41.95
  • MagPul BAD Lever: $25.95
  • Law Tactical folding adapter: $199.99 (I got mine less due to a writer discount from Brownells, but that’s not a discount everyone can get).
  • AR15 Solutions pistol buffer tube: $24.95
  • Carbine buffer and spring (used from a commercial tube I purchased)
  • Primary Arms MD-07 red dot sight: $79.99
  • Transfer fee for the lower: $20.00

Build total not including magazines or shipping (some was free, some wasn’t):



I’m very happy with this build so far.

I don’t intend to carry it in a briefcase, but this design constraint forced me to make decisions that helped me reach my goals of a shorter, lighter, more convenient rifle.

However, this isn’t the final form. I am still trying to get someone to build me a 6″ barrel or shorter, and I could have reduced the overall length by another 3/4″ by using an A2-style flash hider. Unfortunately the A2’s flutes were almost completely obscured by the Midwest Industries free float handguard and I had to go for the longer, safer Kaw Valley Precision linear comp.

I also think I can trim the weight down even more by going with the magnesium alloy lower from MAG Tactical. I’m not 100% sold on carbon fiber handguards, especially in a situation like mine where the rifle is going to get jostled a lot as an everyday carry item.

Stay tuned, everyone.

About the Author:

Short Barrel Shepherd Short Barrel Shepherd is a regular guy and works to make Web sites and mobile apps easier for people to use. He spends his free time attending fight-focused firearm, knife, and combatives training, motorcycling, writing, and playing games. His daily carry is a Glock 19 pistol and an AR15 .300 Blackout pistol in a backpack.

16 Comments on "Let’s Be Brief: My Briefcase AR15"

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  1. FiftyCalAl says:

    I am considering doing a Blackout shorty, but the same reason I prefer the 5.56 platform over a 9mm is keeping me in check on this – the internal wall penetration factor. A 5.56 will break apart quickly in Sheetrock compared to buckshot or pistol ammo, and certainly as compared to the penetration of a .30 projo. Did you consider 5.56? What is the shortest direct impingement action barrel length to insure functionality with 5.56? Thoughts? Thanks!

  2. nDjinn says:

    If you have $360 + more money for internal organizers/pockets checkout the Arc’teryx Khard. I have one and it’s about the best most modular pack I have had in years. It was designed somewhat to hold the HK MP7. You could easily put a folding AR pistol in one. I use if for my “run around Alaska” pack for my personal stuff. Camera and lenses, small first aid, snacks, tablet, and softshell. Mine is in charcoal, they also have coyote and multicam. The Khard is a 30L pack, there is a 50L Khyber for $500.

  3. Stephen says:

    It appears you have room for a 30 round magazine in the case. What caused you to choose 20 rounds vs 30 rounds?

    As I write this, I realize you don’t use the briefcase for EDC. So was the 20 round chosen because that is what you use when carrying in your backpack?

  4. Stephen says:

    You’ve inspired me. I’ve spent the last few weeks researching parts for a build like yours. I want to dump some thoughts and ask some questions to get feedback from you and anyone else coming across this page:

    1) I wanted a 6″ barrel, but that means having one cut from a shop. GrimReaperTactical.com and HoustonArmory.com both offer this, but I have not heard back from either on pricing. I’m assuming the cost of a quality barrel to be cut to a custom length is going to cost more than the 6.75″ Ice Arms barrel.

    2) I wanted 1:7 twist for potentially shooting larger-than-220 grain subsonic bullets. But custom ordering is the only solution to that without going for a longer length barrel. 1 & 2 could be solved if I decide that getting a custom made barrel is cost effective and worth the time and effort.

    3) Handguards: (almost) nobody makes shorter than 7″ handguards. The only one I could find was YHM’s Micro (YHM-9809A:Mini) which is 4.15″ and too short for what i want. I am thinking either getting the NSR 7 and hoping the muzzle blast doesn’t have adverse effects on it, or cutting down the NSR or KMR handguard to the length I need.

    4) muzzle device: The shortest one I have found is the Carlson Mini Comp (CC440). It is technically a compensator, but unscientific reviewers say it does help with the flash a bit. For shortness it is the best I’ve found. Anyone have one that is this short or shorter that specifically tries to address flash signature?

    5) Shorter than 6.75″ barrels seems to lose a lot of performance and gain in complexity of getting the parts and tuning the action. I used QuickLOAD to create estimations of the velocity, ft.-lbs. and powder burn rate of various barrel lengths shooting supersonic rounds. See the chart here: http://imgur.com/wJMgITK — The numbers may be off as this is my first foray into using QuickLOAD, but it gives a general idea. The cost of going from 6.75″ to 6″ is a loss of 83 ft.-lbs., loss of 85FPS, and a loss of 1.27% powder burn. I could live with those numbers, but then I have to look at the dollar cost of a custom cut barrel and custom cut handguard. Going below 6″ means that you are getting close to hitting the gas block with the muzzle device and would require potentially more custom work. But the biggest drawback of going from 6.75” to 5” barrel comes in the lost energy. From 6.75″ to 5″ you lose 217 ft.-lbs. of energy, loss of 229 FPS, and a loss of 4.14% burn rate. The burn rate being somewhat important if you want to reduce the flash signature (not to sound too mall ninja, but I’d be mostly concerned about interfering with my follow-up shots under dim lighting conditions).

    6) Buffer Tube: The KAK Industries Super Sig SB-15 Pistol Buffer Tube (plus the Sig SB-15 arm brace) seems like a good fit for your project. Still legally a pistol, but adds some length that when folded is not a loss for the project goal, but gives a gain in ability to control and usability when extended. The only drawback for me is that I want to use 7075 aluminum components for everything in this build, and because KAK doesn’t specify on their website, I assume it is made from 6061. I’ve emailed KAK and hope to hear back on this. – and in preparing this comment I did more research on this and found Phase 5 makes the Hex-2-C Pistol Buffer Tube which is made of 7075-T7 and provides (as far as I can tell) all the benefits of the KAK. 🙂 Either way, I’ll post back here after I’ve heard from KAK.

    I’ve also just found http://amalgamatedti.com/arms.html — Titanium stuff. Very expensive, but a curious concept.

    • Short Barrel Shepherd Short Barrel Shepherd says:

      Hi there, you covered a lot of material here, so I will try to answer as much as I can. Please forgive me if I forget to address anything, and respond with questions if you’d like.

      1) I would not deal with Houston Armory or Grim Reaper Tactical. GRT has a very negative reputation for taking money and not delivering anything. My personal experience with Houston Armory is that they never would take my money in the first place. I just checked my notes, and the last I heard from them was January 1, 2014. Not sure what happened to Bill over there, but I was ready to buy.

      ICE Arms does not have a great reputation for their 5.56 stuff, but dozens of SBS readers have purchased .300 barrels from them and I have yet to read or hear any complaints. I’d say buy a 6.75″ barrel that exists vs try to get a 6.0″ that doesn’t. I even contracted with a local manufacturer of custom AR15 parts and they flaked on me.

      If you’re going to go custom, the spendy but reliable company is Lothar Walther. This may also address your second point. I can’t own a suppressor here in Minnesota, so twist rate for bigger projectiles isn’t something I considered.

      3) I looked at a UTG Pro super short handguard before going with the Midwest Industries tube. The Simple Threaded Devices muzzle attachment I have is the perfect length to both clear the tube and not stick out too far.

      4) I’m not sure how long that comp you referenced is, but the STD is 1.67″ long, which is about an additional 1.050″ length to your barrel when threaded down tight. See more about it here on Amazon: http://goo.gl/efiwXt

      I did a night training class with the STD and did not notice any adverse muzzle flash.

      Let us know what you come up with!


      • Stephen says:

        1) Thanks for the heads up on HA and GRT. Did not know that. Bill from HA got back to me after about 5 days, that was yesterday. I replied and am waiting on his next reply. His price range is $250-450. He also recommended sending the parts for the upper and they would put it together and tune it. I don’t know if the price range includes that service or not. — After what you’ve said, I’m likely going to go Ice Arms, but I thought I’d relay the info for anyone curious about them.

        I’m glad to hear there is a lack of complaints regarding Ice Arms’ 300 BLK barrels. I was skeptical, but apparently Green Mountain supplies Ice Arms barrels. And GM has a generally positive reputation. That combined with your using the 6.75″ barrel without issues makes me feel comfortable using the same.

        4) The Carlson Mini Comp is 1.302” overall. Based on your numbers (0.62” removed from the total length) the added length should be 0.682”. I think I’m going to give it a shot and see what I think. The biggest draw for me is the lack of added length. I really wanted to go with the AAC Blackout T51, but it adds 1.875″ to the overall length. Which when you’re dealing with a 6.75″ barrel adding 1.875″ seems like a LOT of length. I also was aiming for a platform I could run suppressed, but I’m giving that a lower priority due to lack of 1:7 twist but primarily due to a lack of short length quick detach muzzle devices.

        It may be many months down the road. But I’ll give you an update when I get it together. I’m shooting for a higher end build and my funds right now are not supportive of such an endeavour. My goal is to get everything mapped out, researched to death with data, and then start buying parts.

      • Stephen says:

        A quick followup: I spoke with KAK about their extended pistol buffer tube and confirmed it is made with 6061 aluminum.

    • Matt says:

      Odin Works makes a 5.5″ free-float K-Mod handguard.

  5. Tim says:

    I wouldn’t worry about CF hand guards. They use the stuff on cars, bikes, aircraft, etc. Unless you hit your pistol with a hammer regularly, CF would be plenty tough.

  6. Will says:

    You mention some gun failures here: “…part of the class is a 3-magazine move-and-shoot drill. It’s crippled the rifles of more than one student…”

    What was it about this drill in particular that was problematic to the rifles in use? Any common reasons for failure?

    • Short Barrel Shepherd Short Barrel Shepherd says:

      Hi Will! I think the 3-mag drill exposes problems with over- and under-lubricated rifles, incorrectly adjusted or assembled parts like gas blocks, optics, and muzzle devices, and problems with barrels. It also betrays weak accessories like sling mounts or optics risers. Most of the problems are on AR pattern rifles, there are just so many moving parts and options compared to other rifles that I think it increases the chance of things going wrong. The 3-mag drill may be the first time people have fired their rifles continuously without stopping, adjusting, shooting again, etc. While ~100 rounds isn’t a lot, the movement and concentration of fire seems to do a lot of rifles in.

  7. Big Dave says:

    Hi, Shep. Nice article. I appreciate your complete parts list. I too used Kies adjustable gas blocks until they went out of business. Now that Sryac has a UBER light piston kit (16 click adjustments!), I will be using that on my short barrel build. I only believe in pistons for such short barrels, especially if shooting suppressed.
    You are seriously short changing yourself by over looking carbon fiber hand guards. There are so many excellent brands. They are unbelievably rugged and tough. I will not use any other type now. They protect from heat and cool faster. I like AP customs.
    I too will be using the Gen3 Law Tactical. I love the concept, but they are all steel now, and are quite the little bricks. They add a significant amount of weight that must be parred in other areas. For instance: ATI Omni Hybrid Upper and Lower and an AP Customs hand guard. Hopefully Syrac will come out with a low mass carrier. I am trying to adapt one from Adams Arms/Voodoo Tactical to work with the Syrac piston kit.
    Just food for thought.

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