All right, been following this forum for a while, and the story begins like this.
I bought a century CETME about a year and a half ago from a gun shop as a consignment for $400 out the door with one mag, no sling, plastic furniture and the standard century compensator. I looked it over, not knowing how to check the bolt gap off the top of my head. I had fired one once before and new the basics of it. I looked it over good and the chamber and bolt was dry and the action was gritty but didn't have any wear marks.
And so i took it to the range, loaded some PMC .308 and fired. First round went off and ejected fine and hit in the 10 ring at 25 yards (all I had to work with). The second round didn't go off and had a dented primer. I chambered it again and it fired. It did this a couple of times, so I chalked it up to not being clean or lubed and I didn't have a cleaning kit with me and so I called it a day.
Cleaning it I found the the bolt carrier was not ground down, and there was no wear marks on the inside of the receiver. The firing pin extended past the bolt so that looked fine. So I cleaned it well making sure to hit the flutes as best I could and went back another day. It worked better but still had FTF ever 3-4 rounds with dented primers.
So the next thing I did was polish the coating off the the inside of the receiver with a dremel and buffing wheel, reading that sometimes the friction slows the carrier on the rebound and causes it to not fully seat in the chamber. Again, it works better, but on average of once to twice to a mag it does the same thing with multiple mags (trying to reduce variables)
So now I decided to hit this from a couple of angles. I ordered a new hammer spring from military gun supply, a new G-3 recoil spring and firing pin from RTG. However, in trying to remove the pin from the recoil rod I bend it. So I order a stripped assembly from Apex, and received a full recoil assembly. In trying to assemble it I take the stock apart and around the large stock screw there is a cut piece of aluminum tubing, with the marking still on it. Has anyone seen this before???
Anyhow, I put the new parts in and check and recheck the bolt and cocking tube gap, .018 and .033 recpectfully with standard rollers. I then put some blue loctite on the cocking tube pin since it moved pretty easily. Let me tell you, it charges one hell of a lot more nicely now. Much smoother. The only other thing I need to get is a cleaning kit from E&L. I put a full mag through it yesterday with no problems, first time ever.
Just figured I'd put something up to show the lengths I've gone to in order to get this to run right. I'm gonna put a lot more rounds down range before I call it completely good, but I feel better now. I've added a low profile UTG mount and a primary arms M4 with the spacer removed too. But has anyone seen the aluminum tubing around the screw that goes into the recoil buffer???