my bushy 16" did a pretty weird thing apparently..........noticed it while cleaning the gun

apparently somehow, the carrier key, instead of slipping over the gas tube that protrudes into the upper receiver, hit the tube and they bent each other

i was able to file on and fix the carrier key, but the gas tube i couldnt get to, the tube is not really bent, but it was "cut into" at the end by the carrier key, gun still works, but questions are:

why and how did this happen?
will this affect the functioning of the rifle?
how can i fix it or prevent future happenings?

thanks

You may have bent the gas tube when cleaning, the key may have become loose, or a double feed may have bent the tube.

All three are a guess, but as long as the key was tight to the carrier, then something bent the tube, and only you would know the answer to that question.

nope, i didnt bend the tube while cleaning, the tube, as far as the straightness is not bent, what happened, is while the carrier key and tube are supposed to fit one inside the other, apparently this time they didnt line up and hit each other instead, clear cuts into each, they obviously hit each other...........carrier was tight

Sounds like the tube may have been out of alingment from the start, and when it got hot, it moved some more.

The one thing that I will do on a new key is to clean up the  opening to remove any burs (use slightly greater angle counter sink) and the opening shape edge (if you do get deflection, it's less likely to do some damage to the tube).  Then pull the hand guards (allows you to bend the tube to the correct location/center) and test the tube to key on a very slow lock.  If needed, I will slightly bend the stock tube to make sure that it is feeding dead center in the key. It helps to pull the bolt to be able to see the tube enter the key, and feed the carrier with my finger to see the relationship of the two, due to slop/movement of the carrier in the upper.

Best bet is to order a new gas tube for when the old one takes a dive or just replace the damaged one. Since the gas tube is fairly cheap, and I haven't seen the amount of damage to your tube, you may want to just replace the tube since fishing the broken end out of the key could be a real bitch and turn the rifle into a single shot at a less that ideal time.

Hope this helps in some way,

Dano

If the carrier key was tight and the tube was not bent, there are only 2 other possibilities

1) Double feed like Dano said and it pushed the tube to one side and it got hit...although this scenario's highly suspect.  An event like this you would know about and remember.

2) I would check to see if the barrel nut is on tight.  If the barrel nut has come loose, it could pull the tube off center enough...maybe.  This is a dangerous scenario so make sure it is still tight. That means removing the handguards.  There is no other way to properly assess this.

though everything was going so fast, the gun did have a failure of some sort, i cleared it before even looking, it may have very well been a double feed and it forced the bolt carrier to the side.  tube was and still is straight and dead center.  we were having a south texas arfcom shoot, bunch of class 3's and us po' boys were bump firing.  i'll probably order a gas tube and carrier key to change out later and just run with what i've got now.

thanks yall

now if i can just figure out the problem with my ar-10 armalite, that bastard runs great clean as a whistle and dripping with clp, then about 60 rounds later it starts to go to shit, its a whore about being dirty at all

The ar-10 is a easy one, the chamber is tight as hell.  Once the chamber starts to foul, it's bind city.  The easy solution is to chamber polish to loosen up the chamber a touch.  This will allow the rifle to run, even if it starts to foul.

trying to buy a new gas tube from bushmaster, still not really up to par on my AR knowledge but im getting better.

standard gas tube would be for a 20" so i suppose i need a gas tube for a CAR?  carbine AR?  the 16" tube, yes?

also, what is it gonna take to install this thing, can i do it?  i have lots and lots of tools, but no AR specific tools.

thanks

Unless your barrel is the dissipator model you need a car length gas tube. The tube is pinned to your front sight base.

1.) You need to take a small drift punch and tap out the roll pin holding it in.

2.)This is where it gets interesting, hopefully you can slide the tube back toward the receiver, then pull the tube out of the front sight base. On my gun I had to loosen the sight base first, slide the sight forward rather than slide the gas tube back into the receiver.

3.) removing the front sight means you need to pop out the two pins that hold the sight to the barrel. I would squirt a little oil on the pins and let it soak. You need to look at the pins holding the front sight on and see which end is smaller. The pins are tapered so they will only pop out one direction. I don't remember off hand.

Leave the front sight on the barrel, just punch out the little roll pin that holds the tube, put a few drops of CLP of the tube/housing hole and give it a few minutes to soak in, then pull the tube.  

Since the old tube is history, if it doesn't pull straight out, grab the tube with a set of pliers and use a hammer on the side of the pliers to drift it out.  Just remember to grab the tube a couple of inches down from the front sight in case you squeeze the tube and snap it off.