I'm just the inverse - like the Pierce mag extensions and really dislike the Hogue Jr'.s grip so much, removed from both 709 & 740.
Same problem I had on range, plus kept riding up and covering mag release making it difficult to operate. I trimmed, flipped them end to end, but refused to glue to pistol. Really tried to like them, but finally twisted once too often and gave to range officer to give to someone that would appreciate them, cause I sure didn't.Same for me! I found the grip twisting as i shot..