Reader Donald writes:
The one concern I have building [a bolt carrier group] myself is staking the gas key. I have seen a guy on Youtube do it with a $80 dollar tool but was hoping not to have to buy anymore tools for this build. What’s your thought? Can I stake it with common tools like a center punch or should I try and find a gunsmith to do it for a fee?
So, for the uninitiated, two questions here. First, what does it mean to “stake” the gas key, and what does it do? And second, is it a DIY kind of thing? . . .
The AR-15 bolt carrier has a protrusion along the top called a “gas key.” During the firing sequence, this gas key accepts the hot gasses that have been bled from the barrel and redirects them into the piston chamber area of the bolt, causing the bolt to unlock and forcing the bolt carrier group backwards cycling the action. It’s an essential part of the operating system and needs to be flush with the bolt carrier surface in order to keep the gas from escaping before it can pressurize the piston.
The AR-15 BCG was designed in a time when forming things on a lathe was all the rage, and CNC machines were still a distant pipe dream. Which leads to the cylindrical design of all the AR-15 parts. It makes lathe machining easier. This also means that the bolt needs to be rather circular, so something like the gas key would need to be added later.
The gas key is held in place using a pair of screws set into the part. These screws need to stay tight in order to keep the bolt carrier together and keep the spice gas flowing. Unfortunately, one of the problems with using screws on a part that moves back and forth very quickly is that they tend to work themselves free after a while. And once they work themselves free, they can cause malfunctions and other issues in your gun. In other words, bad news.
How do you keep those screws from coming free? The answer is a practice called “staking.”
The idea is that you permanently deform the outer material surrounding the screws to apply increased friction to the screw heads. It allows you to still remove the screws if necessary (with the application of plenty of force) but keeps the screws from working themselves free under normal wear and tear. In theory, at least.
In practice, it doesn’t always work. My pre-1994 DPMS upper receiver has seen some heavy use, and the gas key is starting to work itself loose despite the gas key being staked. It’s gotten to the point where I just give the screws a good torque after every range trip just to be sure. However, if the screws weren’t staked, the wiggle would have been much worse and it would have happened sooner.
The best option is to ask a friendly gunsmith very nicely to help a brother out. The process takes all of five minutes, and since they should be all setup with vices and punches and a large hammer already, it won’t be a burden. Even if they want $40 for the pleasure, I’d lean towards handing over the cash for a professional job. Sure, you could eyeball it with a screwdriver and a large hammer, but (A) you’re going to bash the crap out of your anodizing which will lead to rust and (B) it won’t be as effective. Either buy the $80 tool, or pay a gunsmith.
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$80 tool? When I ran a company arms room, we used a hammer and a center punch. After I left active duty, I got a punch from Home Depot for about $5 that does the same thing, and it works fine. A screwdriver is certainly the wrong tool, but I don’t believe you need to break the bank, either.
“keep the spice gas flowing.”
Not the first “Dune” reference on TTAG and certainly not the last. Nick, I genuinely appreciate them and your unashamed nerdiness. Well-armed and well-provisioned nerds shall inherit the earth.
Walk without rhythm, and you won’t attract the worm.
Dune reference FTW!
My local gunsmith has all the same vices I do… bourbon, cigars, gun porn. He does have a couple of vises I’d like to have.
Red loctite is only good until about 500 F (I thought the same thing until I read the datasheet). True there are epoxies and resins out there that would easily meet the temp requirement, but there’s a potential for having to deal with VOCs during mixing. Punches will give you a lot less cancer.
Guns in Jewish hands made a difference in the Warsaw Ghetto.
So this guy has no law enforcement or military training, has never fired a gun, and has no experience in combat or defense tactics.
As far as I can tell his entire security qualifications consist of being able to breed.
Why is anyone taking his advice on anything? I’ve never been to med school, but I have kids of my own – should I dispense medical advice?
WTF is going on in this country? We really are a bunch of sheep being led to the slaughter.
I’ll gladly listen to advice from security professionals – preferably people who have actually been shot at in their line of work and survived. They can actually tell you what works and what does not.
I came out of retirement in January and went back to work at a California public school system. At all the schools I have worked at, elementary, middle and high schools you could just walk off the street and into the school grounds. No cctv, no locked gates and in many cases no fences. Campus supervisors who are unarmed and mostly middle aged + women. The only armed response is at the high school level. SRO’s are assigned to each high school.
It has been more than 3 months since Sandy Hook, years since STockton and columbine. difi, biden, barry, bloomie etc. are doing nothing to increase school security and their wasting of effort to try and grab guns is losing time and resources that could go to increasing school security.
Any further school massacres at undefended schools will be at least partly their fault.
People, if you do not like it…move. I am sure that there is someone who is like minded out in the west who would be willing to take you in and help you out until you get back on your feet.
Couldn’t the Rambo wannabes find a more remote place to play SEAL Team 6 member?
Someday, future honest and brave, historians will look back on this era saying the people at one time had a chance to keep their liberties and the historical documents that were later burned up in piles with the banned books.
Kimber makes seven round mags.
Typical racist remark by two-cheeseburgers Moore. I don’t care WHAT the race is of the person – or Government – who is trying to do harm to me or my family; I WILL protect myself.
This war will never end. There will ALWAYS be some group of people that think they know better than the masses, and willing to force it onto them.
“Those who expect to reap the blessings of freedom must, like men, undergo the fatigue of supporting it.” -Thomas Paine
“The condition upon which God hath given liberty to man is eternal vigilance; which condition if he break, servitude is at once the consequence of his crime and the punishment of his guilt.” -John Philpot Curran
A-freaking-men. Freedom isn’t free. You have to claw and fight for it eternally. If you look away, even for a bit, you can lose it all. America got fat and happy for a while and let the gov have their way. Now we’re fighting to prevent things getting to the point of no return.
Greater men than most of us framed the governing body of the nation and the states for moral men to protect the rights of the people. I can count the number of “moral” men on capitol hill on one hand and have five digits left.
I believe Nick is the stats guy in the fold. I would ask him to produce a map of the US with red dots marking spots where all this gun violence is taking place using the FBI data. Dots should vary in size by the numbers. It should be interesting and I’d love to see that presentation. Chicago’s dot could cover IL.
one Russian buried an axe in another for supposedly cheating at chess
Completely understandable.
Josh Earnest? Is this for real? A government mouth-piece, whose name translates to Fool Sincerely? A perfect name for a stand-up comic, but not a spokesperson. Goes double for a Fedgov spokesperson.
There is, definitely, a long-standing policy in this country to disarm the poor, especially the urban poor, and there is most certainly a history of racists attempting to disarm the non-white, though I’m not sure there are recent, overt examples of that.
But there seems to be an assumption in Moore’s head that gun folks are in favor of such discrimination. Are we? I don’t think so. I’m personally in favor of everyone who wants a weapon having one, with the exception of those with a violent criminal history or the seriously mentally disturbed.
THE CRIMINALS ALREADY HAVE GUNS. Making guns unavailable to the poor only renders them defenseless to bullies.
Fact: the more you resort to manhood insults in arguments the higher likelihood you have to suffer from micropenis. The More You Know.
Well I’ve seen unstaked gas key screws back out from regular use. Sounds like 16V is too good for such a “primitive” thing as staking the gas screws, but for the rest of us it is a simple and effective solution to keep them from backing out, and I fail to see the downside of it.
Bolt cutter will create a nice stake, just don’t rush.
CDC ,,. The bullet Flu thru his skull,. sick and tired of people.
I really wish people would stop with the archaic practice of staking. If you want to do it, fine but stop telling noobs it is necessary. 56 inch of torque and red loctite is far better than bashing metal together.
I read these comments and some buffoon always has to chime in on his uninformed ‘properly staking’ advice. Go to young manufacturing to see more.
Red or blue Loctite or the expensive green bearing seal Loctite will lock those screws in as good as or better than staking will. Staking is not foolproof anyway. I put some green Japanese thread locking compound on the Allen head shoulder bolts, ran them in at 55 inch pounds using a Utica torque wrench, and put I two small dimple marks per screw using a Klein all metal awl on one gun and just used the green Japan made thread locking compound on another gun. The staked key actually started to leak. The impact from staking likely broke the Japanese version of Loc Tite free. The mating surfaces were lightly coated with Permatex 80008 #1 or slow drying #2 gasket dressing sealer. My father was a diehard original gray goo Permatex fan. After many many hours spent scraping Permatex off of gasket surfaces, I prefer Hylomar blue now. It is some sort of a super magical non-silicon blue goo sh** that Rolls Royce uses on their jet engines and it just works like a dream. It doesn’t EVER harden but it won’t blow out either. You clean it up with brake parts cleaner and a rag. Even after 4 or 5 or 10 years stuck to a water pump gasket, it just wipes off. Cylinder heads? Yes! Exhaust manifolds? Maybe not, I never tried it. Gas keys? No problems. So I am okay with either Permatex or Hylomar. Those surfaces are small enough it’s not that much scraping, say compared to a timing chain cover or both the heads on a V8. My dad had an old Colt 600 series. Those gas keys were staked on with a simple hammer & a punch. I put some of that green Jap thread lock on a large fan blade center nut. It took a lot of beating on a big wrench with a bigger hammer to get that sucker backed off again. It was bad enough, I’d rather risk it unscrewing itself and taking out the radiator. It’s fine for gas key bolts! They ain’t coming out!