Tweak,
Sorry I didn't get my idea across.
I wasn't disputing the torque value you gave for the barrel extension. I was Refering to the torque of the barrel nut assembly to the upper receiver.
31-35 fp torque didn't seem like a lot and as I understand it, the whack will cause the barrel nut assembly to turn in the receiver (please let me know if I have "assumed" here). That's why I figured light taps would be best, at least initially.
BTW, that 31-35 ft lb was for the torque wrench used in combination with the combination wrench. I don't have the conversion formula handy so I don't know what the actual torque value for the receiver is.
Anyway, to answer your question it's a Colt M-4 new from the factory (or so I'm told).
I fixed the FSB today. I held the rifle across my thighs while seated as Tweak recommended. This allowed for immediate feedback as to just how hard I was tapping the FSB. When I reached the "charliehorse imminent" level of force, I moved the rifle closer to my hip. A couple more whacks, slightly harder than before, and the FSB appears almost perfectly verticle. The front sight post is still about 1/16 -1/32" slightly right of "perfect".
I was reluctant to use additional force to move the FSB the last fraction of an inch. I'm going to the range tommorow and see how it shoots and go from there.
Minuteman419,
I didn't have to hit the FSB all that hard and the plastic faced hammer didn't even leave a scratch. I did hit the FSB below the "ears". Less leverage but I was afraid of bending or breaking it.
Thanks for all of the helpfull advise.