First step . . .
Local club, find someone ex-military and ask them to take a look at it.
Most anyone who was ex-military and had to learn to field strip/shoot an M1 Carbine should be able to at least point you in the right direction as to what's wrong.
Second step . . .
Take a look for M1 Carbine forum/website they probably will have the military field manuals or a pointer to them. Very useful in T/S the gun.
You may not need a gunsmith to fix the problem, whatever it is.
Third step . . .
If you really need to pay someone to fix it, head up to Four Seasons. See Tom and have him take a look at it.