Very interesting stuff here. So can someone define the frame sizes as they correlate to our commonly used 0,1,1 1/2,2 etc.?

Hard to tell from the example I showed since only 20 and only a few 12g guns are listed.

I just checked my photos of the other page from that same book and it is the same deal. All 20g guns with only two 12g labeled the same way. As 2-3/8 frame size.
They were making a lot of 0 frame 20s that week.

In the days of hand written frame sizes in actual frame size columns (around 1928), I was able to confirm in the research for my article on the Hayes Prototype Trojan that sizes written as 1/2 were actually 1-1/2. But this earlier frame size oddity does not make much sense at all.

Chuck,
Are you able to maybe take a tally of what you see by way of those fractional number markings and how they correlate to the bore size. However, we are talking about 1881 as compared to 1913. So no doubt there may have been some differences.

Dave, Dean and Bill clarified that in earlier posts. Charts on page 45 in the Serialization Book and page 527 in The Parker Story correlates the inches width of bolsters to frame size. The 2 1/2 at the factory was a #3 frame stamped on the gun, and so on. Brian, it makes sense if we realize that the later books use the sizes actually stamped on the gun and the earlier books identify frames in inches and fractions of inches.

Once again..... look at the chart in the ID & Ser. book on page 45 re: Column F 'width across the bolsters' for frame size 2 is 2 3/" as I spoke of in my earlier post.

Ok. I see now. So now chuck can add frame size to letters.

Its a curious thing that we generally measure the distance between firing pins centers in discovering the frame size but rarely, if ever, refer to other dimensions of the gun. Possibly there is a difference in this measurement between a 1-frame 16 and a 0-frame 16.... I sispect so without looking at the chart again.

Also, why would they mark an 0 frame as 0 but the others as the bolster measurements?
And... they were marking the locking lugs with the common 0, 1, 1-1/2, 2 etc... So why would they record them differently in the book?

By process of elimination, I don't believe the numbers are DAH, as guns of that period were almost always close to 3" and more. I also don't think it's loads, because they were usually 2 3/4 Dram Equivalent or greater.
I have to believe Dean is correct. I only have one 12 bore hammer gun, and it is a 1 frame, measuring 2 1/4" across the breach face. The column which shows, what I assume are gun weights, matches guns one would assume were heavier, i.e. 12 30" 12, 32" 10, 30 ", 10, 32". It would make sense that a 10 bore with 32" barrels, would be heavier, and logic would suggest they were on larger framed receivers.

I think I will save this discussion to my files. Right now I'm going to warm up a 2 1/4"gun at the skeet field......:)

I have an interesting thought. You could start a new thread.and have members measure across the balls and submit it along with the serial no and the frame size if so marked. Then someone with the serialization books could take the serial no match it to the ones in the book and see if that measurement corresponds to the no's in the book. Soon you would build a data base and confirm deans theory. Then you could possible use that information to determine frame size on guns that are not marked. Just a thought