Oldelkhunter: Thanks for explaining the probable cause of my UL woes.
I am not sure that is the reason you had issues with your UL but I have heard repeatedly about the larger calibers and barrel whip. FWIW my Kimber Montana would shoot a beautiful 3 shot group on a cold morning and then would go all over the place if you did not let it completely cool down and it was a 270 WSM. I think the UL has a beefier barrel.
