I need help from the experts here in MO. Went to my favorite LGS and the guys there know I look for Marlins so they showed me an 1894 carbine microgroove 357 magnum. It has gold trigger, 19XXXXXX making it a 1981 birth year. All looks good except they noticed that the chamber looks too big for a .357 so they dropped a 357 round in it and the round went in about an inch inside the chamber! I asked them if they had slugged the rifle, they said not yet. They just got it and was about to put it out on the rack. Not sure what it is so I turn to the experts here. Any comments appreciated. I did not see any sign of rebarreling, no bad screws all seems intact. It's puzzling. Help!!! I want to buy it but need to make sure first.