Gas Piston Installation | Adams Arms Conversion Kit

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It has been awhile since we posted a how to install the Adams Arms gas piston system instructional and it is nice to hear the variances of how different people do the install. This video posted on Vimeo by Andrew Walker (featuring Mike) can be viewed here. Below is a video transcription for those of you who would rather read than watch of the gas piston installation.


We are basically using just standard, household automotive tools for installing the Adams Arms gas piston retrofit system.

  • Brass, plastic mallet type hammer
  • Good ol’ Huskey Allen key set
  • A couple of punches to remove the front sight block
  • Wrench for removing the muzzle break

As always we want to make sure our weapon is clear of any rounds in the chamber. We want to take the upper receiver from the lower receiver. Remove the carrier bolt and charging handle. We are going to go ahead and remove the front sight. There we go. You are going to either want to use a receiver block, one that grabs the outer edges of the receiver, or a receiver block insert. This is mainly to remove the muzzle break. Sometimes, if you keep the weapon assembled you can actually put it in between your legs and use your legs at a fulcrm to pop the break off. They should be on there snug, but not to tight to where they come off semi easy. Using the block and the vise helps a lot. Now what we want to do is remove the muzzle break; “lefty loosy righty tighty.” That didn’t take much force. Go ahead and remove it.


Now, everyone’s washer set up is going to be a little different. Usually the standard washer set up is one crush washer that’s Milspec, these are peel washer that comes with the sure fire breaks but not everyone is going to have those. Then, what we will want to do is lightly tap on the front sight block just to break it loose; I’m using my plastic end. There we go, the gas tube comes out with the front sight block and remove the retainer. I would recommend cleaning the gas hole area a little bit. Next thing you want to do, is re-remove the upper assembly from the block and the Adams Arms’ kit is going to come with a guide for the upper receiver, it is doweled on both sides. It is designed to go inside the receiver where the gas tube came out of. The kit does come with a rod assembly to help push it in. I want to use a little bit of grease that will help install it into the upper receiver. You want to turn the barrel assembly upside down; barrel downward. I usually take some tweezers, grab the assembly, lay it in there lube down. Then we want to use the guide rod; take your time on this, don’t want to beat everything up. It will be a little finicky until it lines up, so you are going to have to mess with it a bit. On the rod there is a flat end, and a rounded end, you want to use the rounded end so it will sit inside the collar. You also want to make sure that the gas tube opening is semi clean to help with installation. This is the most difficult part of the installation and you have to take your time with it too. There is your operating rod guide installed in the upper receiver. You will see it is set in below flush.




Next thing we want to do is disassemble the bolt and carrier assembly. You want to break the gas key, pull it lose. It is going to be staked so it needs a little bit of force. Go ahead and remove those; these are the old screws you don’t need them afterwards. The kit is supplied with new screws. There is the gas key removed, go ahead and wipe it back down. We want to take the new gas key and install it on the carrier. It does have a post on it where the gas key tube opening was at. It is going to be reinforcement basically. You are going to set into that hole right there, and then your other two opening should line up with the openings on the Adams Arms kit. You are going to have to tap it into place a little bit; nothing too severe. Then you will see everything lined up and it will sit into place; holes are lined up. There are two new Allen bolts that are included into the kit; one longer one shorter. The longer one is going to go to the front, the shorter one is going to go to the rear. It is not necessary, but I always put Loctite on anything with a bolt, you never know if it is going to come loose. Go ahead and start off with the smaller one, put a little dab of some blue Loctite on it. Let it fall into the hole and we are going to go ahead and tighten that up. Don’t want to torque it yet. Same thing with the longer one, let it also fall into place. It is recessed at the rear so it will fit correctly. You will kind of notice as you torque it down if the carrier here and the gas key placement is up a little bit it will set it back into place correctly.


The next thing we have, is our existing bolt. Adams Arms has a spring operated bolt assembly, basically your spring is going to slide over the end of the bolt itself. What this does is if there is any, it will prevent any carrier tilt and it will simulate the DI systems gas pressure pushing back on the bolt and carrier assembly. No one else has this, it is proprietary to the Adams Arms kit. The spring is included in the kit and will go on as such. We do recommend removing the gas rings unless you plan on running your weapon on full auto the gas rings are not needed. Nothing else on the bolt has to be modified. Go ahead and insert the spring, and go ahead and slide it right back into the carrier. It is going to have some tension on it now, so make sure to hold that in place and put in your retainer. Not going anywhere. Go ahead and reassemble the bolt assembly, firing pin in, retainer back in. That is how it should move and operate once the spring is installed correctly.

We are going to go ahead and take the Adams Arms block. Make sure your adjuster settings are to the front, and then also make sure the bolts are loosened up. I prefer to remove them completely. What we want to do first, is Adams Arms does supply a new collar for the M4 handguards. This is the old collar with the hole in it and this is the new collar with the cut out for the kit. You will install it in the same way the standard collar came on and then install the block. Might have to shake it back and forth to get it into position and obviously you want to have that some what lined up. You want to eye ball your block to the receiver. If you are going to use a continuous rail you can also use your detachable handle as a guide also, but eye balling it is usually going to be pretty close. You will notice if it is not lined up that the plug will be a little tight falling in and out, that way you will know if it is a little off center. Then, what we want to do is I normally put red Loctite, the hot stuff, on gas block bolts because it does get kind of hot. Drop two in and we don’t want to torque them down just yet just want to get them snug. Keep in mind as you are tightening these down, there is a possibility the block could rotate on you so keep an eye on it.


Next thing you want to do, is make sure the guard retainer is somewhat lined up, and you also want to make sure your delta ring openings are lined up with the gas hole. There we go, make sure all debris is here. Go ahead and take a look at it; make sure everything is moving freely. This is your plunger assembly. Basically it is going to go in at the 9 o’clock position. It will not let you put it in any other positions. Go and push that in, depress the button, rotate it to the 12 o’clock. Everything looks like it is working correctly, check side alignment again. What we are going to do now is test fit the carrier and bolt assembly with the charging handle. What I am doing is putting the carrier assembly into the upper receiver and I am going to disconnect the plug. You can tell there is a little bit of tension on it. You want to kind of get a feel for it. Push the carrier all the way forward and that is where it contacts, so on this particular model we have about a quarter inch of movement. That is what we are going for and if it is hitting up against that too much you just want to back the block out a little bit. That is going to be your difference in barrel variations, where your cuts are at so we want to keep the carrier depressed forward and see if it feels good and not smacking up against it. You want to rotate it and there is barely any movement there. Loosen this up a little bit because I felt just a little bit of play in there, don’t have to loosen it up a lot. This will take up any slack, then depress the carrier forward again, put the plug in and rotate it to the 12 o’clock position and there is just ever so slightly movement there, but it is touching the carrier. Really important, you want to make sure it isn’t slamming up against the carrier. That way you don’t have any issues with the system. Like we said it is designed to basically push the carrier not smack it. Any time you want to loosen anything or torque it down you want to make sure it is still lined up and it looks like it is still lined up; it looks like we are good.


What we want to do now is install the M4 handguards. You are going to notice that these are included in the kit and is already recessed out for our piston kit, but you can run rail systems with this kit. If you want to use the delta ring, there are a few manufacturers out there: Daniel’s Defense, Troy MRF system will fit as a drop in also. You can use complete rail systems that are continuous; Daniel’s Defense also makes some kits and Samson definitely makes a lot of kits for us, and their kits will work with our piston system. Arms SIR system will also work. There is a complete listing on the website that will tell you which ones will work and which will not. You can use other ones with some modifications. I personally used Midwest Industries on my rifle length and basically drilled out part of the upper rail and it works great, took about an hour. You can do that with other rails also, but that is the nice unique part of the kit, not only are you stuck with the handguards but if you want to run a rail you can run just about anything out there to a degree with some modification or no modification. On this kit right here, we have a Troy Industries MRF system that works great with the Adams Arms. You can see where it has the clearance in there for the kit and everything. To show some variance we have a Noveske MUR upper that also works with the system. Any Milspec receiver will work with our system.


Now, what we are going to do is install the handguards that are supplied with the kit. We are going to have to go head and put in our carrier assembly because for all intensive purposes we are done. Now, keep in mind with this spring loaded carrier we want to run the battery home and then depress it in. Looks like everything is working correctly. We don’t have any excessive friction or anything that is noticed in there. We are going to use our handy de-ring compression tool to go head and help with the install of the handguards. Make sure on the top that you are using one that is already dremeled out and recessed. Now what we want to do again is take our operating rod, I usually put my rifle like this and it usually just falls right into place. One thing is also you want to make sure the delta ring is lined up. We want to install the gas block and now what we want to do is re-install the muzzle break. We want to make sure we put all the timing shims back on correctly. Re-install the muzzle break and torque it down, making sure it is lined up and we are good! Lubrication wise our instructions say you can run it dry obviously we have a mechanical item here metal on metal so there are a couple of areas I would recommend you put lubricant on. I normally will put it on the top of the carrier there and then right up here, this will guide on the upper receiver. Just a thin coat of TW25 will work great. Anywhere you see wear obviously you want to run a little bit of lubricant just a smidge. Remember to depress the carrier, lock it down make sure you have good action and that’s really all you need!


Hopefully you found this tutorial helpful in your own gas piston installation.

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