[quote=2-piper]
"...In the final analysis, much of this measuring of chambers is philosophical; time might be better spent analyzing how many angles can dance on the pin-head of HomelessJoe (who is now batting Zero for Four in the non-contribution meaningless-quip department)..." EDM
So to net it out, you're OK with the plan to use 2+3/4" plastic star crimped hulls in this SxS Colt...thanks !!
I personally don't shoot old Damascus guns--or new ones. However, to add more confusion to an already confused and opinionated subject, I drug out my antique ammo collection, and here's what I found:
Parker Bro's brass:
10A shells measure: 2 5/8"--2 14/16"--2 15/16"--3 1/16"--3 1/4". Being brass they, of course, didn't unfold upon firing. Being brass they would be harder than paper to fit in a close-tolerance chamber. The A-size had the same nominal outside dia. as same-gauge paper, and all these shells pre-date 1900.
12A pre-1900 shells measure: 2 9/16"--2 5/8"--2 7/8".
Conclusion--No nineteenth century 12A or 10A brass shells actually measure 2 3/4-inch.
I have a rare ca.1873 Parker Bro's brown paper shell; this would be one of the first paper shot shells commercially made in America (by UMC for PB). The shell measures 2 7/8-inch open.
And here's a surprise: A Robin Hood pre-1915 paper shell, never roll-crimped, new and unfired measures 2 13/16-inch; meanwhile, a once-fired twenty-first-century Federal Gold Medal paper shell (star crimp) measures 2 3/4-inch exactly. By the way, I ran ten flats of the Federal paper through my several "modern" black-barreled Parkers and loved them! And truth be told, I have never measured a chamber (other than watch Lawrence DelGrego ream the chambers, to no apparent avail, on my AAH Pigeon Gun).
Going back to the archives I find that the Bismuth/Eley I lamblasted above measure 2 7/16-inch closed, are marked 2 3/4-inch, and opened to 3-inches at firing. The Kent Matrix "Impact" 2 3/4-inch waterfowl loads were 2 5/16-inch unfired (1/8-inch shorter than the Bismuth/Eley unfired, and 1/4-inch shorter when fired). I am presently blowing off cheap ($5.99 x 25) Federal 2 3/4-inch/70MM "Top Gun" trap loads at clays behind the barn; unfired they are 1/32nd-inch longer than the Kent Impact waterfowl loads, and fired they are 1/32nd-inch under the 2 3/4-inch standard, which they are marked. Point being that measurements are somewhat subjective.
I have lots of old paper shells taken from boxes in my collection (I remove the heavy ammo and bag it in storage to save the boxes). Unfortunately these ca.1880s to 1930s paper shells are unfired and will remain so unless someday I really have nothing to do, and an old gun to do it with (assuming the old ammo might actually go off). However, no two brands have the same unfired length, varying by as much as 1/8-inch. Maybe blowing off some of this old ammo might produce some reliable measurements that could make the 2 3/4-inch controversy just much adoo... Investigation continues.
Caveat: I never recommend ammo or shooting qualities of guns. There has been talk of Bell and Armbrust "proving" the old guns they tested with modern proof loads and over-proof loads. Many people seize on the results in re: guns not their own. I consider the precautions they take, like firing the guns sand-bagged down using strings tied to the triggers while hiding around the corner of a substantial building. Many of my friends shoot their old "wall-hangers." Different strokes...but if I was going to shoot a 19th century Damascus gun I'd take precautions, maybe even have it test-fired with modern 18,000 psi proof loads. But that's just me. EDM
