recent purchase of 1937, M12, 12 ga. . seems to be all there, needs some tlc. wish to restore it. most all machines have their little quirks, anyone have experience with this, what parts to look hard at etc.. what parts wear out , or should always be replaced. i have a poyer book, and a govt. breakdown manual on the way. any other good books ?, etc.. any info would be appreciated, of any sort, pertaining to this model . thank you