Fit is hard to put into words, but fit is fit
I have seen fore end wood that ran hard against the barrels at the back end, meaning one had to push hard on the fore end tip to get things closed up. That strained the wood, as well as whatever fixed the wood to the iron. In operation, it probably wasn't doing the knuckle and pin any good, either.
If the wood bears hard on the barrels at the tip, the same thing will happen, but there is not as much leverage involved in getting things to go together. Anyone out there had a loop pop off?
I just acquired a gun that has the rub marks you describe, but the forearm fits beautifully. I have to think it was originally fit very close and, knowing that some movement will always occur, so too will some rub. No harm, no foul.
As to a strictly metal to metal fit, you see that a lot in trap and skeet guns and heaven knows how much use they get without failure.
