Chamber Length?

[Ian Byrkit]

Why is it when a Parker has 2 5/8" chambers it is said that it is fine to shoot 2 3/4" shells? I have also seen people state 2 7/8" chambers are fine for 3" shells. Any insight will be apreciated.

[Richard Flanders]

Pull out a bunch of 12ga hulls of various brands, paper and plastic and measure how long they actually are. Many will be less than 2-3/4".

[Bill Murphy]

The real reason is that Parker bored guns 1/8" short as a company policy. The secondary reason is that a plastic shell that intrudes into a forcing cone 1/8" does not create any pressure difference over a plastic shell that does not intrude in a forcing cone at all. Shells that are a bit longer than the chamber length are just no problem unless the chambers are very old and square ended for brass shells.

[LarryAngus]

Although my grandfather's Trojan 16 guage has not see extensive use over the past 40 years there have been times of extensive use. Grouse hunting in New York when my brother was stationed at Plattsburg, dove hunting in Florida by me and pheasant hunting by me in California. We have always used off the shelf 2 3/4 shells". I still don't shoot it as much as my modern guns but my gun is 98 years old so I am ordering some RST 2 1/2" quail and pheasant loads just to preserve my family heirloom and preserve the pristine original stock for my grandson. Probably help preserve my 58 year old arthritic shoulder also.:)

[Richard Flanders]

Bill: I figure that Parker made the chambers 1/8" short so that the fiber and card wads coming out of the paper case mouth would get a bit better gas seal and produce less blowback and chamber fouling if the case mouth was into the forcing cone a bit. Does that make sense??

[william faulk]

Although my grandfather's Trojan 16 guage has not see extensive use over the past 40 years there have been times of extensive use. Grouse hunting in New York when my brother was stationed at Plattsburg, dove hunting in Florida by me and pheasant hunting by me in California. We have always used off the shelf 2 3/4 shells". I still don't shoot it as much as my modern guns but my gun is 98 years old so I am ordering some RST 2 1/2" quail and pheasant loads just to preserve my family heirloom and preserve the pristine original stock for my grandson. Probably help preserve my 58 year old arthritic shoulder also.:)

Larry,I assure a 2 1/2 "..with 7 1/2 shot will knock those pheasants just as dead as any lenth shell or shot load.I used the RST shells first of the month on Pheasants and knocked a few down at 35-40 yards.:)

[Pete Lester]

I believe from material I have read 2 5/8" 12ga shells were loaded to lower pressures than 2 3/4" shells. I am not sure when 2 5/8" in shells were discontinued. I have a VH from 1927 that was ordered to have 2 5/8" chambers.
The Remington Shur-Shot box below contained roll crimp paper shells and a warning to not use in Dam or Twist or chambers shorter than 2 3/4".

http://i269.photobucket.com/albums/jj57/nhshotgunner/234shells.jpg

[Ian Byrkit]

I have a DHE 12g that was made in 1928 on route and the seller says it has 2 1/2" chambers. I find it hard to believe a 1928 DHE would be 2 1/2" when many of the guns 25 years older were 2 3/4". Do you think he miss measured and they are 2 5/8"? If they really are 2 1/2" would it damage the gun to use 2 3/4" 3 dram 1oz 7 1/2 target loads? Thanks!

[ed good]

makes sense in these days of high pressure ammo to shoot shells that when open, are no longer than the chamber. logic says that it reduces pressure and perhaps also recoil, thereby minimizing the possibility of wood cracking and shoulder bruising? like the rabbi said "it dont hoiet".

[Bruce Day]

.....like the rabbi said "it dont hoiet".


Francis! Welcome back!

[ed good]

bruce: come to think of it, the actual quote was:

"it wont hoiet"

or was it:

"it wont be long now"...

its been so long, i thankfully dont remember...

[Dave Noreen]

I've got a 20-gauge VH-Grade, 0-frame gun that was shipped in 1930, and it has 2 3/8 inch chambers intended for the 2 1/2 inch 20-gauge shells.

The "Standard" North American 20-gauge shell throughout the first quarter of the 20th Century was 2 1/2 inch, and the vast majority of American 20-gauge doubles were chambered for that shell. The 2 1/2 inch 20-gauge shell of those days carried a maximum load of 2 1/4 drams of bulk smokeless powder (DuPont, E.C., Schultze, Empire, Wolf, Mullerite, etc.) or 18-grains of dense smokeless powder (Ballistite, Infallible) or 24-grains of Walsrode and 7/8 ounce of shot. Longer 20-gauge shells were offered at extra cost in 2 3/4", 2 7/8" and 3". The long shells advantage was more and better wadding for a better gas seal, and a slightly hotter/faster load. In the 20-gauge they were offered with a slightly hotter/faster load with 2 1/2 drams of bulk or 20-grains of dense smokeless powders (Ballistite or Infallible) or 26-grains of Walsrode but still with only 7/8 ounce of shot.

http://img.photobucket.com/albums/v316/Ansleyone/Rem-UMC/20-gauge3-inchRem-UMCArrow.jpg

http://img.photobucket.com/albums/v316/Ansleyone/Rem-UMC/20gaArrow27801.jpg

All the manufacturers would chamber for the long shells upon request at no extra charge in a new gun. Back in those days the chamber length usually wasn’t marked on the guns and the only way to know for sure is if the original hang tag or factory records still exist.

[Ian Byrkit]

Great info and pictures, thanks. Was it common for a 1928 DHE 12guage to come with 2 1/2" chambers?

[Dave Noreen]

No. the "normal" chambering for a 12-gauge Parker was 2 5/8 inches, intended for a 2 3/4 inch shell. Slight variations in chamber diameters make measuring their depth with most chamber gauges very problimatical. I find this method better for me --

Chamber depth is considered to be the distance between the breech end of the barrels and the joint between the chamber body itself and the forcing cone, which reduces down to bore diameter. This is loosely based on the length of the "Fired" shell. Today, theoretically when the crimp opens on the shell being fired the end would land at the junction of the chamber and cone. Prior to WW-II many companies had the practice of holding the chamber about 1/8 inch shorter than the shell for which it was intended. Fly in the ointment is nominal measurements often differ from actual ones in both chambers and shells. A very good method I have found of measuring chambers without much outlay of cash, and is quite accurate enough for virtually any situation, is a common 6" flexible machinist's scale which you likely have. Hold the barrels with muzzles toward a light source, not necessarily a concentrated one a window is great, while looking into the breech and the cone will be thrown in a shadow. May have to move the barrels around a little until it is distinct. While still looking into the chamber simply slide the scale in until you observe the end coming flush with the shadow line & mark position of breech end with your thumb. Remove and read the scale. I usually repeat this a few times to insure I am getting a consistent reading, but you will be amazed how accurate this can be done. While I own a Galazan chamber gauge, I use this more often than not. The chamber body itself has a taper of about .005" per inch. Sometimes chambers were cut with slightly worn reamers giving a slight undersize chamber. If the chamber is a bit undersize a gauge made to "industry" standards will not go in to the true depth of the chamber. A.H. Fox Gun Co. shotguns are known for having tight chambers. The machinist’s scale method can be more accurate.

For some reason, American shotshell manufacturers dropped the 2 5/8 inch 12-gauge shells and the 2 1/2 inch 20- and 28-gauge shells with WW-II. They did continue to offer the 2 9/16 inch 16-gauge shells into the early 1960s. I use to have a SAAMI chart that listed pressures for the old shorter shells, but the ones I find available now just give 11500 psi maximum pressure for all 12-gauge other than the 3 1/2 inch magnum.