Chamber Length
- Thread starter BigG
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Funny you should bring this up, as I just bought a 1930 16ga A-5 with 2 9/16" chambers today. The little research I did (a couple hours ago) indicated that late-WWII was roughly the cutoff (at least with respect to 16ga Browning A-5s), although some 2 3/4" chambered models date back to at least 1939.
One of the fuzzier recesses of my mind recalls reading a magazine article (probably in The Double Gun Journal) that contained the sort of information you are looking for. If I get a chance a little later, I'll dig through my back-issues and see if I can find it.
One of the fuzzier recesses of my mind recalls reading a magazine article (probably in The Double Gun Journal) that contained the sort of information you are looking for. If I get a chance a little later, I'll dig through my back-issues and see if I can find it.
I don't believe there was one year when chamber length was standarized although I'd venture a guess and state that any post WWII guns would be 2-3/4".
You can still get different chamber lengths in European guns. I've seen 2" and 2-1/2" 12 gauges out of Europe and it's always worth having a chamber length gauge if you are thinking about buying a British made shotgun. Many of them have 2-1/2" chambers that were either shot with 2-3/4" shells or had their chambers, ahem, lengthened by gunsmiths who didn't understand what they were doing.
Paul
You can still get different chamber lengths in European guns. I've seen 2" and 2-1/2" 12 gauges out of Europe and it's always worth having a chamber length gauge if you are thinking about buying a British made shotgun. Many of them have 2-1/2" chambers that were either shot with 2-3/4" shells or had their chambers, ahem, lengthened by gunsmiths who didn't understand what they were doing.
Paul
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Dave McCracken
Moderator In Memoriam
Some US makers changed up by 1930, some not until 1940. Note that not all makers told the truth about when also. With loads available then, a SLIGHTLY short chamber oft gave tighter patterns, and ones that were marked 2 3/4" were in fact often short by a hair. Stevens comes to mind, and Ithaca's wonderful SBT.
Brian Dale
Member
I Had No Idea ...
Remington Model 11 (same design as the A-5) in 12 ga., Mfd. 1915. The kind with the teeny, almost triangular safety button inside the triggerguard, immediately in front of the trigger. The one you pull back toward the trigger to engage. Yep, I wrote engage - to put the gun ON safe, you pull back on the tiny stud right in front of the trigger (I understand that many of you knew this already, but it's fun to marvel about it). In retrospect, I suppose it reinforced Dad's lessons about trigger awareness, back when I was a teenager hunting the cornfields. Not so many lawyers in 1915.
I read your posts, got a chopstick and gave it a good, square corner at the tip with some sandpaper. Felt the end of the chamber; marked it with a pencil and Great Lands, Mildred! Right at 2 5/8". I haven't shot it very much in the past few years, but I sure shot it a lot before that. And I can promise you that it hasn't had anything other than modern, 2 3/4" shells through it since 1974. Maybe some paper AA hulls in the '70s, but mostly plastic, with modern wad designs.
Every Day. Especially around here, I learn somethin' every - single - day.
How hard is it to get suitable shells, or to size them properly once I start reloading?
Remington Model 11 (same design as the A-5) in 12 ga., Mfd. 1915. The kind with the teeny, almost triangular safety button inside the triggerguard, immediately in front of the trigger. The one you pull back toward the trigger to engage. Yep, I wrote engage - to put the gun ON safe, you pull back on the tiny stud right in front of the trigger (I understand that many of you knew this already, but it's fun to marvel about it). In retrospect, I suppose it reinforced Dad's lessons about trigger awareness, back when I was a teenager hunting the cornfields. Not so many lawyers in 1915.
I read your posts, got a chopstick and gave it a good, square corner at the tip with some sandpaper. Felt the end of the chamber; marked it with a pencil and Great Lands, Mildred! Right at 2 5/8". I haven't shot it very much in the past few years, but I sure shot it a lot before that. And I can promise you that it hasn't had anything other than modern, 2 3/4" shells through it since 1974. Maybe some paper AA hulls in the '70s, but mostly plastic, with modern wad designs.
Every Day. Especially around here, I learn somethin' every - single - day.
How hard is it to get suitable shells, or to size them properly once I start reloading?
BigG
To answer your question the year 1926 was the primary year of the 2&3/4 inch chamber in both the 16 and 12 ga. I'm sure there are exceptions but this was the primary year. Wether it always holds true or not I don't know , but it has been said that those guns that are simply marked with the gauge "16 ga." for example are likely chambered for the shorter round. Generaly the guns with 2&3/4 inch chambers were marked as such "16 ga. - 2 & 3/4 inch " Guns marked with just the gauge only should be suspect and checked. I wouldn't rely on the "feel" of an undersize rod however to determine length - a full size plug should be used.
To answer your question the year 1926 was the primary year of the 2&3/4 inch chamber in both the 16 and 12 ga. I'm sure there are exceptions but this was the primary year. Wether it always holds true or not I don't know , but it has been said that those guns that are simply marked with the gauge "16 ga." for example are likely chambered for the shorter round. Generaly the guns with 2&3/4 inch chambers were marked as such "16 ga. - 2 & 3/4 inch " Guns marked with just the gauge only should be suspect and checked. I wouldn't rely on the "feel" of an undersize rod however to determine length - a full size plug should be used.
Brian Dale
Member
Thanks, mnrivrat - I'll hie me to a gunsmith; I think I know just the guy.
Thanks, guys for the help.
mnrivrat: I used a steel rule and measured right down to the corner of the chamber. Clearly this ain't a plug but it is close enough for govt work imho. The Mod 97 measured out at just under 3".
The reason I asked this question for those who don't know is that the chamber length refers to the fired shell. The loaded ctg is less than the nominal length but it needs the additional space for the front of the hull to open up. Firing a 2 /34 shell in a shorter chamber causes the payload to force itself over the partially opened mouth of the hull, with possibly exciting and unpleasant results.
The European shotguns should always be checked, imho, as they used different chamber lengths longer than the US. May still do.
mnrivrat: I used a steel rule and measured right down to the corner of the chamber. Clearly this ain't a plug but it is close enough for govt work imho. The Mod 97 measured out at just under 3".
The reason I asked this question for those who don't know is that the chamber length refers to the fired shell. The loaded ctg is less than the nominal length but it needs the additional space for the front of the hull to open up. Firing a 2 /34 shell in a shorter chamber causes the payload to force itself over the partially opened mouth of the hull, with possibly exciting and unpleasant results.
The European shotguns should always be checked, imho, as they used different chamber lengths longer than the US. May still do.
Thanks BigG -
You of course are correct in mentioning the important safety reason why we talk about chamber length as the chamber has to be long enough to allow the "fired" shell to open without restriction of the forcing cone. The SAAMI specifications for a 2&3/4 inch chamber is 2.750 min. while the modern shot shell should be around 2.720 inches long in its fired state. (refering to 2&3/4" shells only)
Dave mentioned 1930 as the change to 2&3/4 inch and he was correct in siting that as the SAAMI specifications were standardized to 2&3/4" in that year. US manufactured firearms from that year forward should have the min. 2&3/4 inch chambers for 16 & 12 ga. Many guns were produced with that chamber length starting in 1926 . Bottom line is that all guns built in the US prior to 1930 should be checked.
As to your chamber measurement on the model 97 approaching 3 inches ??
You of course are correct in mentioning the important safety reason why we talk about chamber length as the chamber has to be long enough to allow the "fired" shell to open without restriction of the forcing cone. The SAAMI specifications for a 2&3/4 inch chamber is 2.750 min. while the modern shot shell should be around 2.720 inches long in its fired state. (refering to 2&3/4" shells only)
Dave mentioned 1930 as the change to 2&3/4 inch and he was correct in siting that as the SAAMI specifications were standardized to 2&3/4" in that year. US manufactured firearms from that year forward should have the min. 2&3/4 inch chambers for 16 & 12 ga. Many guns were produced with that chamber length starting in 1926 . Bottom line is that all guns built in the US prior to 1930 should be checked.
As to your chamber measurement on the model 97 approaching 3 inches ??
Brian Dale
Member
I think I'll just sit here and listen for a bit. I know that "there are no stupid questions," but I just about achieved it there. Thanks for your patience; you let me make my quota of ignorant mistakes at the keyboard, before I get to the range. (note to self: think carefully before posting late at night)Mike Irwin
Member
Someone once mentioned that they thought that there had also been a 2 7/8" chamber at one time...
I've never seen any references to it, though. Anyone?
I've never seen any references to it, though. Anyone?
Dave McCracken
Moderator In Memoriam
Mike,2 7/8" was standard for the 10 gauge, oft called the Super 10 to differentiate. Some 12s may have been chambered for it also.
Back in those days, proprietary cartridges were the rule.Each maker made his own shells, and oft cut the chamber to fit the shell, not the reverse.
Back in those days, proprietary cartridges were the rule.Each maker made his own shells, and oft cut the chamber to fit the shell, not the reverse.
Mike
And the modern chamber length for 28 ga. would be 2 & 7/8 inch .
To confuse everybody even more one can go to the European guns where some 12 ga. chambers were produced at 73 mm which is the equivalant of 2&7/8 inch.
Dave mentioned variation in manufactures which is also true and just lately I ran across a box of 3&1/2 inch Remington 12 ga. loads that would not eject from a couple of different Mossberg 835's. They were longer when fired than both Federal and Winchester shells and a bit over 3&1/2 inches long when fired . This should not happen if manufactures follow the current SAAMI spec's
And the modern chamber length for 28 ga. would be 2 & 7/8 inch .
To confuse everybody even more one can go to the European guns where some 12 ga. chambers were produced at 73 mm which is the equivalant of 2&7/8 inch.
Dave mentioned variation in manufactures which is also true and just lately I ran across a box of 3&1/2 inch Remington 12 ga. loads that would not eject from a couple of different Mossberg 835's. They were longer when fired than both Federal and Winchester shells and a bit over 3&1/2 inches long when fired . This should not happen if manufactures follow the current SAAMI spec's
Mike Irwin
Member
Thanks, guys!
I'm pretty shure the guy would have been talking about 12-gauge, so it sounds like he was referencing the European 73mm length.
I didn't know about the 10 or 28 gauges...
I'm pretty shure the guy would have been talking about 12-gauge, so it sounds like he was referencing the European 73mm length.
I didn't know about the 10 or 28 gauges...
C.R.Sam
Moderator Emeritus
And then we have the brass hulls...
They come already open
Sam
They come already open
Sam
kotengu
Member.
OK - here's another dumb question: I have an 870 Express (magnum, marked and SR'd), that I put an 18" police take-off on, but its chamber is only cut for 2 3/4" shells. I'm having the forcing cone lengthened - is it possible for my 'smith to lengthen it to take the 3" shells as well, or will just lengthening the taper allow the use of 3" shells?
I don't shoot 3" much (or at all), so it's mostly a moot point, but I'd like to understand the capabilities.
I don't shoot 3" much (or at all), so it's mostly a moot point, but I'd like to understand the capabilities.
C.R.Sam
Moderator Emeritus
If you think you or any one else might shoot threes...
Have him lengthen the chamber;
And so stamp the barrel.
Sam
Have him lengthen the chamber;
And so stamp the barrel.
Sam
kotengu,
Your chamber would have to be lengthen'd as well in order to shoot 3 inch shells. The change to the forcing cone is forward of the chamber and changes the angle of the taper in that area - it does not give any more length to the chamber.
Your chamber would have to be lengthen'd as well in order to shoot 3 inch shells. The change to the forcing cone is forward of the chamber and changes the angle of the taper in that area - it does not give any more length to the chamber.
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