Started working on the second shotgun I got a couple of weeks ago and I'm surprised with this one. It's a pretty plain jane gun except for the gauge. The barrel is marked 17.4 with would be in millimeters and I measure the bore in decimals at 0.677 which comes to a 15 gauge. I have no idea if I can even get wads that size. I can always use tow to load it with but would rather have wads.