Need Help with old S&W 916 12ga pump

[john in jax]

I got a used S&W 916 and it was having 1 or 2 failure to feed issues every mag. Most of the time the shells weren't popping out of the mag. I bought, cut down and installed a new Wolff mag spring and now it cycles great through every shell but the last one. The last shell consistently jams up against the front of the lifter rather than popping up on top of it.

Any hints, tips?

Thanks in advance
John