Group Gripper

I installed a Group Gripper in a GI pistol with a GI barrel to correct a barrel alignment problem. It worked amazingly well (probably better than I could have done filing and fitting for a week), but now my barrel seats too far back on the frame, and LRN bullets won't feed. I know how to adjust the barrel face to cure this (per Kuhnhausen), but I was wondering if anybody else used a Group Gripper, and whether there is any adjustment that can be made to the Group Gripper?

UPDATE: I decided to go with the Kuhnhausen technique, Pp. 67-68. I shortened the throat ramp using a file, cutting the angle as low as possible without hitting the lower lug. Then I blended the new angle into the throat without moving the tipping point. The gun now feeds lead and even empty brass. Group Girpper for the win - The lazy man's way to repeatable lockup.

UPDATE #2: Okay, my shooting buddy and I wrung out the gun today, and we had no problem hitting a 6 inch plate at 100 yards consistently. The Group Gripper "just works". Magic for a loose GI gun.