"...they jam or will not chamber a round..." Needle nosed pliers and tweak the lips open a tick. Takes very little tweaking.
Mind you, it still depends on what make you bought from Midway and/or through Sportsman Guide. Midway shows Promag, well known for being low end stuff. And Auto-Ordnance factory mags that have unreliable availability. Midway gives you 90 days to return stuff that isn't satisfactory
Sportsman Guide lists those and something called Red White & Blue. They say just send it back if you don't like it, but we're not paying for it.