i believe the curve has to do with reliable feeding of the .22LR round in 25 round quantities, kind of like how AR mags dont curve as much as the AK mags, its dictated by the round in the mag
Bullspit. Pistol mags are not curved, nor are pistol style mags that fit in rifles.
The "Teardrop" ruger 10/22 magazine is not curved either and it holds 50 rounds. Same with the drum mag.