Newbie FAL...multiple issues...
I decided to take my CAI(ugh...I know, I know) FAL out monday for a little practice. I loaded up 3 magazines and barely got through 1. The gun repeatedly stovepiped, and failed to fully seat the round. It luckily is the "good" CAI with the correct feed ramp. I never had this problem before the new magazines, and new DSA Scope mount. I did notice it would feed single rounds better than from the magazine. If I pop the slide release, it would pull a round from the magazine and chamber it 2/3 of the way. I also can't figure out how to clean/adjust the gas system It has a grenade? launcher site on the front that I can not figure out how to remove. Do I have to have the wrench to adjust the preasure?
The gas adjustment can be made with a tip of a bullet (or a dull pry tool/screw driver or by hand). The ribbed collar behind the front sight turns. Towards the front sight is more gas to the gas piston. Turning it back reduces the gas to the gas piston by bleeding more gas. There's an angle on the front of it and the bleed hole is in the rear of the sight base. The angled front part of the gas regulator covers and uncovers the bleed hole. In front of the front sight the gas plug has a button on it. Depress the button and rotate the gas plug to remove it. It has a bit of spring pressure behind it from the spring loaded gas piston.
Here are some instructions. Disregard the letters and numbers.
FAL GAS SETTING, FIELD STRIPPING, AND CLEANING
It may also be worth taking the recoil spring out and cleaning out the tube and spring. Mine had cosmoline down in there and caused the recoil spring to be sluggish at times. If your gun worked fine before the dsa scope mount and mags, I'd see if using the old mags or removing the scope mount causes the jamming to stop. Then you can track down why its happening. Like Allesennogwat also mentioned, properly adjust the gas system.
I finally did get the gas tube to turn, it was on 3 I turned it to 5. I'll have to try it at the range and see. I know there is an exact science I'll look up the correct way to set the gas port. I included the picture to get a better idea as to why I can't use the pictures from the the link above. Is the picture I included a range estimator or a grenade launcher sight? Thanks for the help guys!