Are the takedown pins stiff without the upper on it? Are they stiff all the way through or are they just stiff at the ends when they hit the detents? If it is just at the detents, you can remove the springs and cut a couple of coils off the spring and then replace. Take off a little and test it, then if needed take a little more and test again. Makes the takedown pins a lot easier to move.
It is far more important to be able to hit the target than it is to haggle over who makes a weapon or who pulls a trigger.
— Dwight D. Eisenhower