If they're getting caught on the bottom side of the receiver under the feed ramp, you'll have to put a spacer plate in the front portion of the magazine or modify the feed ramp (notch and chamfer, or just chamfer the bottom side of the notch if it's already notched) to keep them from getting caught.
If it's a matter of the rounds nose-diving instead of hitting the feed ramp and feeding, then play with the lips of the magazine(s) or adjust the fit of the bottom metal (the latter is probably a GS endeavor) until you get the rounds at the right ride height to properly feed. Typically with the bolt out of the receiver and a loaded magazine inserted, you should be able to look from behind through the action bore and Juuuust see the primer of the top loaded round, or close to it. If you see well into the primer or barely see the rim, you're more likely to have issues.