The cap or threaded metal ring that secures the forearm to the action bars may be the issue. Remington used to have a special tool for it. I take needle nose pliers and wrap black electrical tape on the ends of the pliers to preclude scratching and dinging the area up. It is a slow process but it will work.
"Without a rifle you are nothing, worthless, you are waiting for death, any minute, any second."
-- Aron Bielski