Useful Tools: Brownells' AR-15/M-16 Carrier Key Staking Tool

Black Friday resulted in quite a few firearms-related purchases for me.  I'd be lying if I said otherwise.  Sometimes, though, what seemed like a great deal in the moment turns out to be a little less awesome when it arrives courtesy of your friendly common carrier.

So it was in the case of a complete AR bolt carrier group that I purchased.  While the price induced me to buy, when it arrived it became quickly apparent that the staking for the carrier gas key lacked something.  And by something, I mean correct execution.  To illustrate, below is a side by side of the gas key that I bought on Black Friday on the left, and a Colt factory gas key on the right:

Clearly, the amount of material displaced in the staking process varies greatly between the two.  Having been through an AR armorer course, I can tell you that the Colt BCG illustrates the correct staking.  So what to do?  Obviously, I desired to correct the issue, because having your gas key come loose while shooting sits pretty high on the list of "crappy things that result in weapon failure."

Enter the Brownells AR-15/M16 Carrier Key Staking Tool, available for $69.99 from Brownells, incidentally where I have purchased almost every AR armorer tool I possess.  The tool embodies simplicity.  It consists of a body with five hardened screws.  Four of these screws provide the staking capability, and the other stabilizes the carrier during the process.

You simply insert the carrier as seen here:

Adjust the tension on the front screw (I kept it just past hand tight), then turn each of the staking screws 1/2 turn at a time until you achieve your desired results.  Once you feel that the screws are properly staked, back them out, release the tensioning screw, and remove your carrier.  You should achieve results similar to this:

Now, I realize that $69.99 tips the scale on the pricey side for those of you who build ARs as a hobby.  But for an armorer who conducts periodic inspections and repairs, this tool will take the guesswork out of staking repaired keys.  It really works just as simply as I described.  I couldn't even figure out how to stretch this article any further - it only took me five minutes to stake the key, and it was my first time using it!

Even though the staking screws are hardened, breakage always remains a possibility.  If you were to break a screw, fear not, Brownells covers you with four packs of replacement screws for $9.99.

So if you serve as an armorer, or just want the ability to stake your hobby guns, check it out on Brownells site.  You won't be disappointed.

Useful Tools: Black Rifle Disease Engineering's Gas Block Dimple and Drilling Jigs

My Black Rifle Disease Engineering (BRDE) gear.  From L to R, drill bits and reamer, Dimpling Jig, and Drilling Jig.

I've always enjoyed building my own rifles.  If I had any machining skill, I'd probably do my own machining, but as it is, I'm confined to assembling my rifles from the machining skills of others.  Of course, I have my personal preferences in parts and layout.  For example, I believe that gas blocks should be pinned for long term durability, not simply attached by set screws.  Obviously this can be a problem, as most gas blocks don't come with the ability to be pinned.

Enter Black Rifle Disease Engineering.  Owned by Jake Carlson, a registered professional engineer, BRDE designs and builds a wide range of barrel dimpling and gas block drilling jigs to fit many of the gas blocks on the market today.  I use the 1A PRO dimpling jig, designed for the Bravo Company Manufacturing gas block I put on this build.  It will also fit other gas blocks with a .460" center to center set screw design, including VLTOR, Rainier, Fortis, Midwest Industries, SLR, Radical, Odin, and CMMG.

The design of this jig is simple, but incredibly effective.  Two screws on the top help locate and hold the jig.  One screw (the blued one) properly aligns the jig by centering itself in the gas port.  The white screw provides additional holding power without marring your barrel through the use of a nylon tip.  The two holes underneath the jig guide the included 11/64" jobber drill bit.  The flat sides of the jig allow you to mount it directly into your vice for security while you drill.

Dimpling Jig on the barrel

Using the 1A or PRO is simple.  Slide the jig onto the barrel, blue screw towards the chamber.  Keep an eye on the gas port, and as the jig covers the port, gently work the blue screw with your fingers until you feel it engage the port.  Due to the tapered end of the screw, it will self-center, and there's no reason to go crazy tight.  Hand tight, plus maybe a quarter to half turn with the hex wrench should set it in place.  When you're confident the jig has centered, tighten down the secondary screw.

Dimpling Jig in the vise

Flip the barrel and jig over and place them into your vice.  I started drilling with the dimple nearest the chamber.  I used regular gun oil as lube for the drill bit - one or two drops should be plenty.  From here, patience - patience, patience, and more patience.  Remember, you're not trying to drill a hole in the barrel, you're just trying to get a divot deep enough for the head of the set screw to rest in.  You get bonus points if it turns out nice and concentric, but don't keep drilling just to get a perfect circle, no one will see it anyway.... Apply steady, even pressure and check your work often.  Remember, we're talking max depths of around 1/16" here.

Dimpling complete

 A note from Jake on nitrided parts:

Melonite or Nitride treated barrels and gas blocks have a very hard surface. Standard HSS drill bits that are included with out tools are not hard enough to cut this surface. If you are dimpling or drilling for pinning, you will need hard tooling. I have had mixed luck using cobalt drills. In this application, I recommend using carbide drills. They are substantially higher cost but in the end will save much frustration. We try to keep the #31, 11/64" and 3/16" carbide drills in stock.

Drilling Jig ready to go

When you're happy with the dimples, it's time to move on to the drilling jig.  My jig is the 2A PRO drilling jig.  First, install the gas block on the barrel, properly aligned, and tightened down.  Slide the jig over the gas block and tighten the bottom set screw.  Once again, one to two drops of gun oil for bit lubrication.  Slow and steady wins the race.  You'll find the beginning and end of the drilling the most difficult, as the bit tries to bite into the angle of the block, and again as the bit exits the block and attempts to align with the hole in the opposite side of the jig.  Clean the bit frequently and apply oil as you feel necessary.

Gas block drilled

The barrel after dimpling and drilling

After you've drilled the block, several options exist for securing it, and BRDE has parts for every option.  First, you can go with my choice and tap in a taper pin.  To do that, you'll have to take the extra step of reaming for the pin.  While simple, reaming does take more time and careful effort, since you'll have to ream, check pin fit, ream, check fit, and repeat until you're satisfied with the fit.  A dowel pin is your second option, and a coiled roll pin your third.  I used a taper pin for this build, but I'm seriously considering the coiled roll pin for the next. 

Fitting the taper pin

Installing the taper pin

I hope this has been useful for you.  If you like to build, and want to add that next level of security to your gas block attachment, don't forget to check out BRDE on the web, or on Instagram!