Confused

[Dean Romig]

Rajan, take an exact measurement between the centers of the "firing pins" and post the measurement here. Someone will tell you the frame size. When all else fails this is what will determine your frame size. The 20 on the bottom of the lug could indicate 20 gauge or it could be a 2-frame with the lighter 0 stamp indicating something else entirely. There are several marks on Parker barrel flats and lugs that we do not know the meaning of.

[Bill Murphy]

The gauge of the gun can be determined by inserting shotgun shells of different sizes in the chambers. The largest size shell that is a snug fit is the gauge of your gun. Judging by the weight of your barrels, (3-3), you probably have a 20 gauge.