Armory Sponsor
Posted: 1/21/2005 3:55:04 PM EDT
|
+1 on the adjustment on the end of the gas tube - under the barrel set to single shot. If it's a new weapon have a close look at the gas system to make sure there's not something buggered up in it - a metal sliver or the like somewhere critical. You can take the handguards off and rest the thing on a sand bag to watch the "moving" parts. |
|
What is happening is that the round is partially being extracted after it fires and the case expands. After the case expands then it is being rammed back into the chamber by the bolt which for some reason does not have enough rearward force to fully extract and eject the round. Does this happen with the gas system closed or on its first setting? If so three things can be wrong: 1. The piston head is slightly too small in diameter, consequently too much gas blows by it. 2. There is a gas leak around the gas block or gas tube near the piston head. This may just be missing the cross pin where the gas tube meets the gas block. Which is an easy fix with a piece of wire coat hanger. Or the gas tube threads may be stripped. This happens when people attempt to unscreww the gas tube without removing the cross pin first. 3. The most unlikely is that the bleed hole in the barrel may need to be enlarged. Supposedly Century guns with new barrrels were assembled with barrels that only had a pilot hole and were never drilled to their proper diameter. Whether this is true or not is really irrelevant. Some guns need to have their gas bleeds drilled slightly larger. This is relatively easy to check and repair. My advise is to go to FAL files those guys can tell you the proper diameter size for the piston head (a cheap and easy replacement) or the proper size for the bleed hole (I can't remember). They will also tell the complete procedure for these repairs so you won't make the gun worse than when you started. This is a pain in the ass but nothing serious. |
|
Your gas piston should measure .430 the gas port on like an 18" barrel can be taken opened up to .116 this would be about right for that length of barrel. It sounds like you have a Inch gas plug the grove should be facing up, if it is not then you ar ein single shot mode. set the gas regulator to about 5 but first back it off and run a pipe cleaner down that hole that is to the rear of the front sight post. Look through the barrel to make sure it goes all the way through, or just use a piece of wire. This is the gas port, drilling it out I would do as a last resort, it should be at an angle like 45 degrees. If you decide to open it up put a piece of wooden dowel in the barrel, start with the smallest size drill bit like .106 and work you r way up to about .116 but no more then .118. One last thing make sure that your gas piston free falls through the gas tube, take it out and turn it around, it should be snug. If it moves laterally then it might be undersized. THen Take the spring off and put it in the correct way let it slide down to the bolt carrier area. Watch it and make sure it is moving striaght through and not to one side or the other, if it is then it maybe getting bound up as it moves rearward. If it is not moving striaght then your barrel could be out of time or th egas piston could be bent. I also have heard some people saying something about a 2 piece century gas piston, this I don't think would be right, allthough I have not seen one. |
|
The gas plug must have the groove on the outside of the plug facing up when installed. I should have mentioned in my last post that the handguards must be removed to do the following checks. Don't forget to check the cross pin where the gas tube attaches to the gas block. The failure to have this pin installed will cause sufficient gas leakage to prevent proper opperation. The gas tube must be screwed tightly into the gas block. CAUTION as I said in my last post the gas tube threads will be damaged if you attempt to turn the gas tube with the cross pin in place. Some early Century guns had a two piece gas piston that would bend and disable the gun I've had my gun about 3 1/2 years and it had a good one piece gas piston so I'm guessing yours is too but it is worth checking. One non-gas system related item. does your bolt carrier ride freely in the upper receiver? Spend time at FAL FILES thats where I learned all of this. Don't lose hope . My FAL is a Century built on a Heese receiver. Many would say that it is the worst FAL but there are alot of us with them that work fine. This one has been perfect and has run great since the day I bought it , and with a little work your's will too. Century FALs rarely have anything major wrong with them. Usually its something minor like a missing cross pin. The only things I've done to it are change the hammer, trigger and sear with FSE components (best $50. I spent, the trigger is outstanding now) and replaced the bolt holdopen pin (the Brit and Austrailians grind these off. another cheap and easy fix found on FAL FILES). The cheapest thing I did to the gun that improved my accuracy with it was to measure the apature of the rear sight with a drill bit. I then cleaned the sight and soldered the apature closed. I then drilled a smaller apature with a drill bit one or two sizes smaller. Surprisingly this has held up for the last coule of years. The original apature size is great for fast work on the battlefield but I found it too large for precise range work (not that the any FAL is accurate enough for real precise work). |
The gas tube can be a little loose and it will be fine. If the gas tube will rotate about 1/16th of an inch left and right, but go no further, then the pin is there and you have no worries. |
Armory Sponsor