10FP feeding issue

[wnycollector]

I have a 223 10FP with the stagger feed box mag. The rifle is a fantastic shooter, but it has an annoying habit of not feeding the 3rd round ~50% of the time. It looks like the rear/rim end of the 223 round slides back/down so that the bolt cant pick it up and just rides over it. I'm thinking it's a weak mag spring. Any thoughts would be appreciated.

[tomme boy]

Lift up on the bolt as you cycle it. I have to do that to my 308 or it misses the shells on the left side.

[stangfish]

Tweak the lips on the mag. You can do it.

[wnycollector]

Tweak the lips on the mag. You can do it.

If I decide to tweak, should I bend the right side lip up (allowing the round to move up)?