I have that same Marlin .22 mag except mine is blued and wood stock. It is not particularly well finished and the mag looks like it would have problems feeding as the tip of the bullet is a ways from the chamber. It sort of looks like the cartridge is hanging in the air.
However it has never failed to feed perfectly and it is one of the most accurate rifles I have ever owned. I am not saying most accurate rimfire but most accurate period.
A few years back Wal-Mart cleared out the 10 round mags and I bought 7 or 8 or them at $5.00 each.
It sort of reminds me of the days when a few guys would have a very plain looking 50s or 60s car. On the outside it looked like it probably had a six cylinder with a 3 on the tree. Look under the hood and it had a 427 with all the extras and a Borg Warner 4 speed, positraction etc.
It doesn’t look like much but it really performs.
It is my favorite 22, i do hate the 4 round magazine. Wish I had been smart (like you) and grabbed a few 10 round mags. Maybe next year when the rush is over. :)
Mine is in .22 LR, but also feeds .22 Short from the mag. It was my father-in-law's. He had it stored in his closet for years, and it had been his trusty squirrel rifle. It was bruised and battered and he gave it to me because he knew I'd fix it up and make it into something. And I did:
Like you said...accuracy that compares to much more expensive guns. Fun to shoot with .22 Shorts...quieter than my Gamo .177 pellet rifle.