Conversion magazines

I Don't know about the current Marvels.
My early Marvel was horribly unreliable-it was the magazines. - I tried a Kimber conversion magazine.-Much better, but not perfect (staggered rounds in the mag didn't rise reliably). - Tried AA conversion magazines-100% reliable- & didn't actuate the slide stop (I heard some do). - The AA mags were a little tight in one lower; a flat file easily fixed that. -I like the AA magazines - use them for the Marvel and AA.

A test: 
Taking all safety precautions, I took my best Marvel steel magazine, loaded 5 rounds and quickly cycled them thru the pistol-without firing them-ejected rounds falling onto carpet. - Repeated with Kimber magazine. - Repeated with AA magazine. - all w/ same Marvel/lower.
Results - grades:

Marvel steel mag: "F"  The rounds/bullets were very beat up-nicks lead scraped off - looked terrible-. Sold 3 for $25.

Kimber magazine: "C"- almost couldn't tell the cycled rounds from new ones. -But there was the occasional problem of rounds hanging up in               the mag.

AA magazine: "B+" - 100% reliable - some rounds very slightly dinged from chambering-not bad at all. -- -had to file down to fall free from 1             lower.
2¢-YMMV --- -Russ

Pro Mags (plastic) A+ never had one fail.

- Dave

Never had any issues with any of the plastic magazines that came with my Nelson. I vaguely remember reading some article or post about why plastic mags are a better choice for 22LR than the steel ones, but can't remember any details.

2 year old lock back Marvel on OLD Colt frame...I never had any issues until the compensator was almost completely plugged.
I have 1 Marvel, 4 Kimber plastic, & 6 GSG aluminum.  They all work fine FOR ME.