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How do I replace a gas tube cover? ESTIMATED COMPLETION TIME: 15-20 minutes 1) BE SURE THE RIFLE IS UNLOADED!!!!! 2) Gather the necessary tools. You'll need a hammer, a punch or strong thin nail, a vice or something solid with a strong thin lip (I use an ammo box), possibly small files, and plenty of patience. Oh, and OSHA reccomends safety glasses, gloves, a safety harness... 3) Remove the GTC from the rifle. Rotate the lever located on the right side of the rear sight to a 45 degree angle. If the lever is hard to move, you may have to pry it with a piece of PLASTIC or some other non-scratching rigid material. You'll notice the gas tube will get pretty loose. Lift up on the rear of the gas tube, allowing the front to pivot in it's socket. You may have to slightly change the angle of the locking arm to allow the tube to come completely free. Take caution to not move or jostle this lever again until the gas tube is replaced in the rifle. If the arm continues upward, it will release a smaller piston that is backed with a spring stout enough to send the connecting rod flying across the room with enough force to put a nice lump on someone's head. (Although I wouldn't know...) When the rear of the tube is free of the rear sight, pull straight back and the tube will come free. Also keep in mind that there is a plunger inside the tube that will want to fall out, so be ready for it.
4) Locate the retaining pin. Depending on the rifle, this is the second most difficult step in the procedure. Look closely. Closer. Closer still. See it? It is located on either side of the end cap at the rearmost portion of the tube. Sometimes it's so hard to find because during assembly the ends of pins were smashed rivetlike into a bevel on the cap. Then, the heads of the pin were milled flush with the sides of the cap. If necessary, take a sharp tipped pencil and trace the edges of the pin's head for better visibility. 5) Position and secure the GTC. Choose well lit area and a comfortable working angle which allows room the pin room to move as you're driving it out. If you want to keep the wooden hand guard, use extreme caution in securing, especially if you are using a vice. I've split the wood in two once before... I prefer working vertically for this job. 6) Ready... Steady... Choose a punch that is approx half to one third the diameter of the retaining pin. Although they look nice and big, these pins are actually the same diameter as a wire coat hanger. I like to use a largish punch to start the job then replace it with a smaller punch in the next step. Line up the punch dead center on the pin. Tap the pin firmly a few times to ensure the GTC is secured properly. The last thing we want is to hit one end sternly and have the other end come flying up at your face. If the GTC is secure and you hit hard enough, you'll notice the flange on the pin start to curl upward as the pin has gone a little deeper into the hole. 7) GO! Carefully begin a series of light to moderate hammer blows and punch repositioning. Work slowly, as mistakes will most likely cause scratches in the bluing on the end cap. If you have a flange on the retaining pin, it is going to have to fit down the hole right along with your punch so frequent repositioning of the punches location and angle may be necessary. The idea is to have the pin's flange roll right up and assume the same diameter as the pin. You may have to switch to a smaller punch the deeper the pin goes. If your new GTC cover doesn't come with a new pin, be sure not to lose the original pin as it falls out of the other end. 8) The 'ol switcheroo. Now it's just a simple matter of removing the end cap and the cover falls right off. Surprisingly grungy under there, yes? Take a moment and clean off all the crud and old cosmoline you can't ordinarily access. Adding the new hand guard may take some minor fitting depending on what kind of rifle you have and what kind of new part you're adding. The steel vented GTC's will definitely require filing to fit the tongue in the groove under either end cap. 9) Inserting the pin. Whether or not you have a new pin to replace the mangled old one, you may want to consider how permanent you want this new cover to be. If you want it to be interchangeable, go to the hardware store and buy a properly sized roll pin and use it to replace the old one. If you want it to be permanent, but want the luxury of easily changing your mind down the road, file the mangled end off the old pin (while out of the end cap) until it's flush with the end caps when fully inserted. The permanent route will require you to fully insert the old or replacement pin, then pound it flat again. After you're finished fitting the pin, you're going to have to file off any burrs or protrusions so the tube fits cleanly into the receiver channel. 10) Batten the hatches. Give your work a once over, possibly refinishing any scratched bluing. A neat little trick I use if I put any small scratches in the finish is to take a black marker and touch up the raw metal. Of course, using some of the spray on bluing is probably best, especially if you filed a lot of the finish off. Now, reinsert the plunger in the tube, reinsert the tube in the rifle, lock it down, grab a beer and admire your handy work because you're finished. MPG (1.6 MB) VIDEO: This is a simple video demonstrating the principles involved in removing the gas tube cover. It may not be exactly how you remove yours, but it shows the steps involved. ADDITIONAL COMMENTS: "One suggestion that came up from other forum contributors
that 'got my gas tube retaining pin to move' was the advice of using the
standard pin punch that comes in the SKS tool kit; it made a BIG difference.
That puppy doesn't mushroom or bend as did the other punches I ruined trying to
get the job done. It's wide enough, tapering at the end to the smaller
diameter you need, to have more strength than the usual punches that tend to
have an inch or so of the same diameter on the skinny end. That punch is
hard carbon steel, it sparked when I whacked it with the hammer to get that pin
loose. It made all the difference." - FRANK H |
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Your rifle and
the gas tube locking lever.
Rotate the arm to
unlock the gas tube.
Pivot the gas tube
up far enough to clear the sight.