I've got an Advantage Arms 22lr and it jams like crazy. Every 3rd round or so.
I've changed to a new magazine but same issue.
Is this a common issue? Are their common remedies?
It's on a glock 17

What ammo are you using?

Stay away from greasy "match" ammo, go with something copper plated, or dry lube lead.

Remington copper plated and CCI blazer

Mine runs on remington thunderbolt and golden

how do you lube/service the kit after a range session?

Mine only runs on Remmy Golden Bullet ammo.

This. The old steel lipped mags would feed almost anything, the newer polymer ones really only work well with the Rem Golden bullets. Has to do with the rim thickness or diameter but it interferes with the extractor.

Probably not pulling the spent shell out of the chamber and then trying to fed another one, right?

'xactly! Faulty mag was my gut feeling because I tried all cleaning./lube combinations. Any idea where to get steel-lip mags?

I wish I knew, I bought a new older AA slide and thats what it came with. Bought a couple new polymer spares and I was less then impressed. What was one almost 100% reliable with almost any .22 ammo went to reliable with rem GB and pathetic with everything else unless I used the steel lipped mag it came with. Now, when I hit the shows, I'm always looking for another steel lipped one.

If you are having functioning problems with an Advantage Arms Glock kit I suggest you polish the chamber.  I use a barrel mob with flitz attached to a variable speed drill.  If an unfired cartridge will not fall out of an AA barrel when the muzzle is raised I suggest polishing the chamber.  Mine pistol works better with the pistol well lubed and I like to use Breakfree.  Pay particular attention to the sliding ejector, if this area gets dry and dirty on my pistol I start having jams.  A lot of AA kits need several hundred rounds before they become reliable.  My Glock 17/22/31 kit has probably close to 20,000 rounds and will function with Federal bulk.  My Brothers new 19/23/32 kit would only function reliably with Remington bulk golden bullets.  It may also help to put a drop of breakfree on the recoil spring guide rod.

Good idea, I'll try the polishing. Rounds fit fairly tight in the chamber and need a bit of force to eject.

My 2 cents.

1.Clean the chamber, then clean it again with alcohol.   No Oil in the chamber, it forms carbon.
2. lube the frame tabs that the slide runs on.
3. CCI mini mags or Rem Golden only. Federal Auto Match maybe.