I bought 2 of them. They are excellent mags, well made of good blued steel
Here's my report...
"well i got to try them this weekend. Tried them on a somewhat battered takedown gevarm. brought a well used original factory magazine as well
I found both new magazines to be a very tight fit at first. however with some oil on the magazines and encouragement with a nylon hammer, they both seated well. after about 10 seatings, they went in & out easily by hand and locked firmly in position. To remove it , it was necessary at times to put upwards (gunwards) pressure on the magazine to get the mag release lever to move. This may have been due to the gun's magazine well being dirty as well. The vertical positioning relative to the bolt seemed perfect (as opposed to the stock one, which had a fair bit of horizontal and vertical slop). both mags accepted 21 rounds and looked like they would take 22. i limited tests to 20
Started with the Gevarm bolt set for high velocity ammo cycling ran remington hi velocity hollowpoints through all 3 mags . the stock mag and one of the new mags functioned perfectly both in rapid fire and slow fire . The second new mag gave me stovepipe stoppages . I attributed this to either the mag perhaps being seated a little high so the bolt was dragging on the top of the mag lips a bit on its backwards movement which slowed it enough so that the empty shell wasn't hitting the ejector (left lip) with enough velocity to clear the chamber (my theory), or possibly the left lip is a little too far forward which means that the accelerating empty hasn't reached enough velocity.. so i reset the gevarm bolt to cycle regular velocity ammo (thereby increasing bolt speed) and the problem went away. the gun also functioned perfectly with a box of federal that I had on hand.
so all in all i'm very happy with the functioning of the mags. i'm especially happy with the tight tolerances on the seating which is a lot better than the stock ones which can give feeding issues if they are nudged out of position. ,The spacing adjustment can be fixed by minor stoning on the positioning notch or the feedlips or the fun route ( which i will follow of course

) of running a couple of hundred rounds through the mag to allow some wearing in".
There was a proposition made a few months ago on this board and some of us ordered them. As there is work involved in setting this up I will leave it up to the gentleman ( and he is that - I recommend him highly) who arranged the first order to chime in. All i can say is that i'm a happy customer...