I have an Advantage Arms .22LR upper on my Glock 22 frame. When I first got it, it worked great - 100% reliable with most hot ammo (Mini Mags etc.) and also with Wally World Remington Golden Bullet bulk pack.

After a long (6 month) spell buried in the back of my gun safe, I dug it out again. For some reason,it will not reliably cycle any of the previously OK ammo. Even hot ammo like Mini Mags (solid and HP) and Remington Viper. The symptom is that the rounds do not reliably feed out of the magazines; sometimes, they get part way into the chamber, then get stuck, with the result that the cartridge gets bent where the bullet enters the case. Occassionally (perhaps when its getting dirty) I get stovepipes and failure to go fully into battery. However, the feeding problems happen even when the entire weapon is scrupulously clean and lubed with Breakfree CLP. Malfs happen maybe once or twice a magazine, sometimes more frequently.

I'm starting to get the feeling that Jonathan Ciener snuck into my gunsafe and switched the AA upper for one of his ;g .

As the symptoms seemed to point to a magazine problem (e.g. weak mag springs, dirty mag), I cleaned both my mags following the AA instructions (hot, soapy water !). This did not help. The malfs seem equally common with both mags too, which leads me to think they are probably OK.

The cases do not seem to be ejecting with a lot of authority, so I am wondering if this could be a cycling issue. However, I'm at a loss to put my finger on what could be causing such a problem. Does anyone here have any ideas ?

Get some "lead out" and work the chamber over once again.   I've had a similar prob in the past and it came down to a dirty chamber.   I thought it was clean.  

Thanks for the suggestion. I had cleaned the barrel, but confess I didn't inspect the chamber that closely before (it looked clean, but who knows. After a long shooting session yesterday, the chamber was, of course, very dirty - I've scrubbed it out (looks like a mirror now) and will test fire again later in the week. I'll let you know how it goes .

OK, I got the the bottom of this:

It looks like the problem was simply a dirty chamber ! Despite starting with a mirror-clean chamber/bore each shooting session, I was first shooting with Remington Golden Bullet loads (the previously "known good" load), and these were apparently causing a lot of residue to deposit on the chamber walls very quickly - like within 1 mag load. When I cleaned the chamber and switched to MiniMags, I had no problems at all (shot 10 mag loads as fast as I could pull the trigger - no malfs).

Why the Remington ammo, which had previously performed flawlessly, now behaves so badly is unknown. I have about 700 rounds of this ammo left - the only gun I have that it will work in is my NAA Mini Revolver... 700 rounds is probably a lifetime supply .

Thanks to everyone for the constructive advice. I'm glad this was such a simple fix.

Maybe they went with a dirtier powder for the walmart bulk box load because of costs.   I don't know.   I've got 2 of the conversion kits and just ran into your problem recently.   Made me crazy for a while til I figured out what was going on.   I just clean more often.

Now if we could only find someone who can make high cap mags for the thing.

Quoted: Now if we could only find someone who can make high cap mags for the thing.

+1... not an effective defensive weapon without hicaps