Hello, just received my MPX SBR and Octane 45HD I have been waiting on. Original plan was to order the shorter 4.5" barrel once I received the gun so the octane would be under the handguard. After reading on the forums it looks like that is not the best way to go and I have researched what others have done and who to send the 8" to and have it cut down. Took the new toy to the shop today to remove the barrel. The first screw/nut came loose without a hitch. The second just spins as others have stated in other threads. I did not want to post in some of the other older threads because I didn't want it to get lost in the shuffle and see if someone has figured out a better way yet that I have not read about. I tried applying heat to loosen the loc-tite with no luck. Put a large flat blade screwdriver in the hand guard groove to apply pressure with no luck before and after heat. Even tried my mini impact with pressure on the blown out rail slot. This is a **** poor design I must say. Anyone have any other ideas before I call Sig tomorrow? I am seriously bent at the moment as I have not shot a round through this thing. Thanks for allowing me to vent.