How many rounds have you put through this gun?
If less than 300 keep shooting it before sending it back.

Do you have more than one magazine?
If so is it failing to feed or stove piping with both? If just one magazine is problematic will the second one feed without problem.

Have you cleaned the magazine then lightly greased the spring?
You should also check for burs on the follower or the inside of the magazine body, pay careful attention to any areas that has a cut out or recess area also look for rub spots on the interior of the magazine body.

Try a different type of ammo, I would first try a round nose FMJ round and see how that goes, then if that works try some hollow point styles, I have seen a few styles of HP's with a plastic insert in the cavity to facilitate feeding.

Hope this helps,

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Thank you
Penmon AKA Jim