Hello all! I am asking for some help on this new shotgun I purchased. I just recently purchased a Colt 1878 double barrel shotgun. The serial number puts it at 1883 for production. It's a 10 gauge with 32in barrels. What I am curious of is what are the chambers? I really can't find anything to tell the size. I would figure 3in but I would like to be certain. Any help would be greatly appreciated. Thanks!!!!