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Posted By: terc Ithaca chamber lengths - 09/12/21 11:36 PM
Hi all,
Since there isn't an Ithaca collectors forum this seems like a good place for my question. I see a lot of small bore Ithaca Flues guns, in almost new, unmolested condition, with 2 3/4" chambers. From what I read they should be 2 1/2". This seems to be much more prevalent in Ithaca guns than other brands. Could these longer chambers actually come from from Ithaca this way or is it mostly aftermarket alterations ?
Thanks, Dave
Posted By: FallCreekFan Re: Ithaca chamber lengths - 09/13/21 12:53 AM
Yes, they should be 2 1/2” (actually 2 9/16”).
Ithaca starts listing 2 3/4” chambers in their 1934 catalogs.
Posted By: Researcher Re: Ithaca chamber lengths - 09/13/21 01:10 AM
While Ithaca would chamber for longer shells if the customer requested, normally the 16-gauge was chambered for 2 9/16 inch shells and the 20- and 28-gauge for 2 1/2 inch shells. When the 20-gauge progressive burning powder, high velocity, 20-gauge 1 ounce loads hit the market in 1922, Western Cartridge Co., Peters Cartridge Co. and Remington Arms Co., Inc. put up their versions in a 2 3/4 inch case. So, Ithaca may have begun chambering their 20-gauge guns for the 2 3/4 inch shells before the catalogue text caught up. Winchester like the others put their 1 ounce high velocity 20-gauge loads in a 2 3/4 inch case, but with all their 20-gauge Model 12s in the hands of sportsmen made for 2 1/2 inch shells, they also stuffed the load in a 2 1/2 inch shell.
Posted By: Recoil Rob Re: Ithaca chamber lengths - 09/13/21 01:05 PM
I had a very late Flues 20, 1925, s/n 3961xx, seemed like it was built on a heavier frame than the early wands, it was 2-3/4, I have no reason to think it was not original. It weighed about 1/2 pound more than an early 20 I had.
Posted By: Researcher Re: Ithaca chamber lengths - 09/13/21 02:36 PM
By the mid-1920s, Ithaca had beefed up their Flues doubles quite a bit. In the 1912 through at least 1915 Ithaca catalogues they give their smallbore weights as --

16-ga 5 3/4 to 6 1/4
20-ga 5 1/4 to 5 3/4
28-ga 4 3/4 to 5 1/4

In the July 1919, Ithaca catalogue --

16-ga 5 lbs. 14 ozs. to 6 1/2
20-ga 5 1/2 to 6
28-ga 5 to 5 1/2

In the December 1, 1919, Ithaca catalogue --

16-ga 6 to 6 3/4
20-ga 5 3/4 to 6
28-ga 5 1/4 to 5 3/4

In the 1925 Ithaca catalogue --

16-ga 6 1/4 to 6 3/4
20-ga 6 to 6 1/2
28-ga 5 3/4 to 6 1/4
Posted By: ed good Re: Ithaca chamber lengths - 09/13/21 09:21 PM
it is sad that the increases in powder pressures, resulting from the deveopment of better ways to kill each other is one of the negative results of ww1...

apparently this change in powder technology carried over to post ww1 shotgun loads as well...resulting in preww1, light guns, such as many ithacas to develop mechanical and reliablity issue that were unknowm prior to ww1 and before the new higher pressure powders came into common use for factory ammo...

and this is why so many fine side lock guns also suddenly started to show fatigue issues...

like the wise man said...an ole hoss can only take so much abuse, before it breaks down an quits on you...
Posted By: Drew Hause Re: Ithaca chamber lengths - 09/13/21 10:58 PM
Fortunately we have numbers to prove that ed is incorrect.

DuPont Ballistic Table that was published in Parker Brothers' “The Small Bore Shotgun” c. 1920
http://parkerguns.org/pages/PDF%20Documents/Small%20Bore%20Shotgun.pdf
It is clear that this table converts Long Tons to PSI simply by multiplying by 2240; NOT using Burrard’s conversion
“All powders referred to on these pages are of the bulk nitro kind ranging from 12 (“New Schultze”, New “E.C. Improved No. 2”) to 13 1/3 (original DuPont Bulk) grains per dram…”
DuPont Bulk was introduced in 1893
"New Schultze" and "E.C. Improved" in 1903
Dense Smokeless powder pressures were higher. "Infallible" was introduced by Laflin & Rand in 1900

[Linked Image from photos.smugmug.com]

Numbers require adding 10 - 14% for modern piezo transducer pressures.
12 gauge
3 Dr. Eq. 1 1/8 oz. = 8,110 psi
3 1/4 Dr. Eq. 1 1/8 oz. = 8,960 psi
3 1/2 Dr. Eq. 1 1/4 oz. = 9,900 psi
16 gauge
2 3/4 Dr. Eq. 7/8 oz. = 7,035 psi
3 Dr. Eq. 1 oz. = 8,980 psi
20 gauge
2 1/2 Dr. Eq. 7/8 oz. = 12,655 psi

Very similar to modern pressures when adding 10-14%, and the 20g far exceeds the SAAMI recommended max. of 11,500 psi

If ed has post-WWI pressure data documenting higher pressures he is invited to post the information.
Posted By: Shotgunjones Re: Ithaca chamber lengths - 09/13/21 11:04 PM
Originally Posted by ed good
it is sad that the increases in powder pressures, resulting from the deveopment of better ways to kill each other is one of the negative results of ww1...

...apparently this change in powder technology..

No such thing occurred, ed.

The change in powder technology was the development of progressive powders.

They develop higher velocity without an increase in pressure.
Posted By: Carl46 Re: Ithaca chamber lengths - 09/13/21 11:22 PM
Shot loads have increased since the 1920 numbers cited. The max load for 20 gauge was 7/8 0z., not the ounce or more we see now. The greater recoil would create a demand for heavier guns.
Posted By: ed good Re: Ithaca chamber lengths - 09/13/21 11:33 PM
so then, why did ithaca beef up the flues guns shortly after ww1? and then eventually replace them with the heavier nid in 1926?
Posted By: Drew Hause Re: Ithaca chamber lengths - 09/13/21 11:37 PM
What SGJ said

From the 1928 edition of “Smokeless Shotgun Powders” by Wallace Coxe, ballistic engineer of the Burnside Laboratory of the E.I. du Pont de Nemours & Co. “DuPont Oval can be loaded with 1 3/8 ounces of shot in a 12-gauge shotgun to develop the same velocity and pressure as obtained with a load of 3 1/2 drams of DuPont Bulk Smokeless Powder or 28 grains of Ballistite and 1 1/4 ounces of shot. The relation naturally holds with other charges, but as DuPont Oval is used principally for maximum loads the comparison is more striking as it shows the possibility of using a heavy load with DuPont Oval that would be an abnormal load were it used with DuPont Bulk Smokeless, Ballistite, or other existing old-style types of shotgun powders.”
Coxe reported 3 1/2 Dram Eq. 1 1/4 oz. loads (the standard c. 1900 Live Bird load):
NOTE: pressures were measured by crushers (LUP) and modern transducer measurement pressures would be 10 – 14% higher
DuPont Bulk smokeless powder - 11,700 psi
Schultze Bulk smokeless powder - 11,800 psi
28 grains of Ballistite Dense smokeless powder - 12,600 psi
Note all 3 are greater than the SAAMI 12g 2 3/4” recommended maximum pressure of 11,500 psi.
40 grains of DuPont Oval Progressive Burning powder - 9,400 psi
Posted By: L. Brown Re: Ithaca chamber lengths - 09/14/21 07:01 PM
Originally Posted by Drew Hause
Fortunately we have numbers to prove that ed is incorrect.

DuPont Ballistic Table that was published in Parker Brothers' “The Small Bore Shotgun” c. 1920
http://parkerguns.org/pages/PDF%20Documents/Small%20Bore%20Shotgun.pdf
It is clear that this table converts Long Tons to PSI simply by multiplying by 2240; NOT using Burrard’s conversion
“All powders referred to on these pages are of the bulk nitro kind ranging from 12 (“New Schultze”, New “E.C. Improved No. 2”) to 13 1/3 (original DuPont Bulk) grains per dram…”
DuPont Bulk was introduced in 1893
"New Schultze" and "E.C. Improved" in 1903
Dense Smokeless powder pressures were higher. "Infallible" was introduced by Laflin & Rand in 1900

[Linked Image from photos.smugmug.com]

Numbers require adding 10 - 14% for modern piezo transducer pressures.
12 gauge
3 Dr. Eq. 1 1/8 oz. = 8,110 psi
3 1/4 Dr. Eq. 1 1/8 oz. = 8,960 psi
3 1/2 Dr. Eq. 1 1/4 oz. = 9,900 psi
16 gauge
2 3/4 Dr. Eq. 7/8 oz. = 7,035 psi
3 Dr. Eq. 1 oz. = 8,980 psi
20 gauge
2 1/2 Dr. Eq. 7/8 oz. = 12,655 psi

Very similar to modern pressures when adding 10-14%, and the 20g far exceeds the SAAMI recommended max. of 11,500 psi

If ed has post-WWI pressure data documenting higher pressures he is invited to post the information.
Posted By: L. Brown Re: Ithaca chamber lengths - 09/14/21 07:06 PM
Very similar to modern pressures when adding 10-14%, and the 20g far exceeds the SAAMI recommended max. of 11,500 psi

[/quote]
As usual, Doc Drew, excellent historical information. However, you slipped on the current SAAMI recommended max pressure. Current max avg pressure figure for the 20ga is 12,000 psi. So the vintage loads were actually higher than the current standard . . . but not by quite as much as you indicated..
Posted By: bsteele Re: Ithaca chamber lengths - 09/14/21 08:13 PM
I had a 1912 20ga flues in otherwise 95+% condition that had 2-15/16” chambers. Also a 30” 20ga flues with 2-15/16” chambers, but it’s condition was much lower and I can’t be as sure it wasn't modified. I know of one other very high grade 20ga flues with almost 3” chambers.

Also, the high condition gun had a “2nd” marked on the barrel lug with no obvious variation from a standard gun other than the chamber length.
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