The last couple of times I've had the FS2000 at the range I've had double feeds, ie, the spent case is partially into the ejection chute and the new round is jambed by the empty and the barrel trunion.  I'm using surplus SA80 and D&H magazines.  The switch doesn't appear to be damaged when compared to a new spare I have.  Ammo is M855.  It takes a screwdrive up thru the mag well hooking the unfired case extractor groove to clear the stopage.  Any useful suggestions would be welcome.
Thanks

Those SA80 magazines were an issue with the SA80 unless they are HK so I would see if these double feeds result with other magazines.

With the ejection system of the FS2000, I wasn't sure what to call my problem, hence the description.  I was sure so high speed, low drag armchair operator would set me straight.  Thanks for trying.

Without firing the gun, if you rack it a few times does it properly eject down the ejection tube?

If so, then the problem is your gas piston...probably your piston rings aren't in the proper offset or one or more of them is shot.

If not, and you're sure that your switch is in good condition.  Contact FN customer service.

After a complete cleaning and a call to FNH customer service I returned to the range today with brand new Center Industries magazines.  After confiriming zero and firing 25 aimmed rounds I shot 3 strings on 10 rounds each as fast as I could pull the trigger.  I had no jambs or malfuctions during to entire session.  I can only conclude that the mags I had been using where somehow defective.  I will try them in other 5.56 x 45 rifles to see if they are truly defective or if the FS2000 must use a higher quality, read newer, magazine due to it's unique charging cycle.
I would also like to thank Bob Ailes of FN for his prompt attention to my problem, his helpful suggestions and his offer of an RGA to ship the gun back to FN.  FN is second to none when it comes to customer service

Good to see you got that fixed.

Honestly, the only mag I had trouble with in my FS was the one it came with. All my other mags run Magpul followers, and have been unremarkable unless they're full of sand or something.