Barrel flat - frame size stamps

[B. Dudley]

Barrels will be marked with the frame size on the bottom of the bolting lug. With the exception of very early hammer guns and barrels that may have had their stamping filed off for some reason.
Determining frame size of the frame itself would require measuring certain areas of the frame. Firstly the firing pin spacing. And for some frame sizes, the height of the standing breech is also an important area to look at.

[Bill Graham]

Originally Posted by Brian Dudley

Barrels will be marked with the frame size on the bottom of the bolting lug. With the exception of very early hammer guns and barrels that may have had their stamping filed off for some reason.

What would be measured on a barrel with no frame size stamp present, and what would those measurements need to be for it to interface correctly with a 1 1/2 frame?
Thank you.

[Bill Murphy]

TPS page 527? has a chart with all the measurements.