First I had to 'tweak' the left action bar slightly
outwards so that it would reliably engage the action bar lock. Once I got it together I noticed that, after I cocked it (empty) and was looking down the sights, the fore stock would occasionally move rearwards, opening the action. This was mostly because I was using the fore stock to pull the gun into my shoulder a little but it's not a good thing. Using a pair of pliers I put about a 1-2mm bend just aft of the notch where the bolt sits in the action bar did the trick. Remember to always #### the gun before diss-assembly or else the hammer will end up hanging in the mag well... not that that ever happens to me!
Brass cleaning rod to give perspective
Second, I put an upward bulge in the followers of both my aftermarket mags to help with feeding (I read about this in a thread here that I can no longer find). The poly-mag that they currently come with feeds reliably, but the metal aftermarket mags I have both fail to feed if they aren't anything but perfectly seated home. Simply disassembling the mags and using a robertson screwdriver (I'm high tech like that) as a punch inside the follower I was able to tap a ~3mm bulge into the top. This tilts the shells up a little more and allows reliable feeding regardless of where the mag is seated. I went a little at a time and used some fired shells (with the crimp portion cut off) to test the cycling.
DA poly mag in the back, both on a flat surface.
Side view of 'the bump'. I used a number 3 Robertson screwdriver but would have preferred something of a slightly larger diameter to reduce the possibility of punching all the way through the follower
Top view of 'the bump'
Third I took a flat file to the Mag release. The edge of the release that actually contacts the magazine was quite sharp and was scraping the metal mags to the point where it would sometimes cause 'fish hooks' on the metal. I simply used a metal file parallel to the back of the mag housing to flatten it out a little so that it no longer digs into the mags yet still reliably holds them. Of course, this operation was a little at a time; file, test, file, test, so I didn't ruin the whole damned mechanism. All of these things took me no more than 15 minutes, once I had figured out the causes of the individual issues.
Not a great pic but you can see the flattened edge here
Demo of how I filed
Beyond that, as others have said, clean the #### out of the thing to get rid of the packing grease and treat it like what it is; a tank! What I mean is don't baby it at the range, rack it with authority and you will avoid feed issues that some experience.
I read in the same thread that I got the mag tip from that some use a dremel, file or some such on the bottom edge of the chamber to remove the sharp edge and thereby improve feeding. I did notice while cycling spent shells through it that the bottom of the chamber does shave a tiny amount of plastic off of some shells, but it doesn't get in the chamber and as long as you are wearing your big-boy pants when you rack it, it won't be an issue.
Oh yeah, stock up on 00 buck and cheap slugs, cause its fun as hell to shoot!
