Steve: same thing happened to me with my 16g 0E after shooting recreational skeet all summer and not breaking down the barrels. I foolishly put a small dab of STOS on the lug, and during the Arizona hell season it solidified into epoxy
I used a 1/2 clothes pin as Bro. David suggested and cautiously tapped it between the FE and barrels. With some effort the barrels eventually separated.
It does help to rest the butt on your thigh while rotating the latch and pulling on the FE.