Early Fox SW 16 gauge with 30" tubes...sweet

[Silvers]

.....When shooting field loads it helps to have the chambers opened, gun will produce less recoil on the shooter and the guns old wood.....SXS Ohio

Ohio, and why is it that opening your chambers to 2-3/4" will produce less recoil on the shooter and the old wood?

Tom, my read on that gent to see for more particulars is "Mr. Overbaugh" = Harry Overbaugh, Fox factory tournament shooter and the company's Southern District Sales rep. He's also the gent who ran Fox's display at the Panama Pacific Expo in SF.

[vaturkey]

.....When shooting field loads it helps to have the chambers opened, gun will produce less recoil on the shooter and the guns old wood.....SXS Ohio

Ohio, and why is it that opening your chambers to 2-3/4" will produce less recoil on the shooter and the old wood?

Tom, my read on that gent to see for more particulars is "Mr. Overbaugh" = Harry Overbaugh, Fox factory tournament shooter and the company's Southern District Sales rep. He's also the gent who ran Fox's display at the Panama Pacific Expo in SF.

Thank Frank. I'll do some digging. Interesting gun. I'm guessing not many were ordered with swivels and cheekpiece and single trigger.

[Researcher]

Here's the back of my card. Really interesting:

A nest of long chambered guns right in that range 2006xx range -- 627 ordered with "3" chambers", 642, 643, 648, 663 and 679 all ordered "chamber for for 3" shells."

[SXS ohio]

Shooting 2-3/4" plastic shells in the old guns with short chambers.....We all want...Less recoil and less shot deformation....When a plastic 2 3/4" shell is fired in a 2 5/8 chamber made to shoot paper shells with no wad cup the longer shells crimp opens into the mouth of the forcing cone restricting the shot and wad that is being pushed at great pressure out of the shell case into the mouth of the forcing cone. By cutting the chamber and cone forward it allows for the added length of the open hull and a little more room for the shot to pass into the bore. Thus a smoother transition into the forcing cone, less pellet deformation, better patterns and less recoil. All this may not be a big deal but does make sense. After the chambers have been done I have lots of modern 16 gauge ammo from light game loads to field loads to shoot. I have never know a working guns value to be effected by lengthened chambers...its just is not a issue with guns we plan to use. That's my story and it makes sense to me. thanks all....SXS Ohio

[Silvers]

Shooting 2-3/4" plastic shells in the old guns with short chambers.....We all want...Less recoil and less shot deformation....When a plastic 2 3/4" shell is fired in a 2 5/8 chamber made to shoot paper shells with no wad cup the longer shells crimp opens into the mouth of the forcing cone restricting the shot and wad that is being pushed at great pressure out of the shell case into the mouth of the forcing cone. By cutting the chamber and cone forward it allows for the added length of the open hull and a little more room for the shot to pass into the bore. Thus a smoother transition into the forcing cone, less pellet deformation, better patterns and less recoil. All this may not be a big deal but does make sense. After the chambers have been done I have lots of modern 16 gauge ammo from light game loads to field loads to shoot. I have never know a working guns value to be effected by lengthened chambers...its just is not a issue with guns we plan to use. That's my story and it makes sense to me. thanks all....SXS Ohio

Thanks Ohio. I've heard similar explanations for years but they don't seem to add up. The only elements in the Physics equation for recoil are: velocity, and mass (weight) of the shot + wad + powder gasses. Shell pressure doesn't enter into it. For recoil to be reduced after lengthening a 16-gauge chamber, the velocity would have to be lower. So how does that happen? Actually it seems like the velocity would be higher, not lower, when that restriction is eased.

Said another way, there's a certain amount of useful energy in the powder and if less of it is used to push the shot charge past the restriction (by means of a lengthened chamber) wouldn't there be more energy available to push the shot charge to higher velocity? And that would increase the recoil, not reduce it.

Back to Physics 101.

[FoxintheHenHouse]

I believe all modern 2-3/4" plastic shells, even low brass you find at Wal-Mart, have much higher pressures than any shotshell made during the production years of the Fox. Modern shells, so-called low brass included, that are sold in most department and hunting stores have high enough pressures to cycle today's auto loading shotguns and should not be used in 1920s & 30s shotguns whether you lengthen the chamber or not. I would suggest staying with any shotshell that designated "low pressure", to be safe.

FoxintheHenHouse

[Researcher]

I believe all modern 2-3/4" plastic shells, even low brass you find at Wal-Mart, have much higher pressures than any shotshell made during the production years of the Fox. Modern shells, so-called low brass included, that are sold in most department and hunting stores have high enough pressures to cycle today's auto loading shotguns and should not be used in 1920s & 30s shotguns whether you lengthen the chamber or not. I would suggest staying with any shotshell that designated "low pressure", to be safe.

FoxintheHenHouse

Not really true. SAAMI specs for shotshell pressures came into effect circa 1925. Granted some slight changes due to the transition from LUP to PSI. According to some DuPont Smokeless Shotgun Powders booklets by Wallace Coxe from the late 1920s and the early 1930s, the heaviest 12-gauge bulk and dense smokeless powder loads offered during the first thirty years of the 20th Century were higher then now allowed. They state that these were 12,600 pounds --

LEADER 28-grains Ballistite, 1 1/4 ounce shot

Leader 28-grains Ballistite 1 1-4 ounce #4CH.jpg (55.18 KiB) Viewed 5745 times

RECORD 28-grains Ballistite 1 1/4 ounce shot

RECORD 12-ga 28-grains Ballistite.jpg (76.08 KiB) Viewed 5745 times

And these were about 11,700 pounds --

LEADER 3 1/2 drams DuPont, 1 1/4 ounce shot

Leader.jpg (75.68 KiB) Viewed 5745 times

The introduction of progressive burning smokeless powders in the early 1920s allowed that 1 1/4 ounce of shot to be moved out at considerably higher velocity and lower pressures.

[Stan Hillis]

The only elements in the Physics equation for recoil are: velocity, and mass (weight) of the shot + wad + powder gasses.

I agree that those three things are the only elements in the equation for calculating free recoil. No argument there. But, I have believed for a long time that there is another element that has not, as of yet, that I know of, been calculated that factors into felt recoil. That is ...... duration of powder burn. I have shot so many different loads in my life it would be impossible to remember and list them all. Many of them were duplicate loads as far as the elements listed .... velocity and weight of the ejecta. However, faster burning powders which deliver the same payload at the same velocity seem to have "sharper" recoil to me. Slower burning powders delivering the same payload at the same velocity seem to be less harsh .... more of a shove. All black powder loads I have ever fired seem to fall into this latter category. Recoil pads do the same thing .... spread the same free recoil out over a slightly longer duration, thus causing the shooter to feel less "kick".

One of those things that may never be quantified but, due to experience, I believe very strongly.

SRH

[Silvers]

I agree that those three things are the only elements in the equation for calculating free recoil. No argument there. But, I have believed for a long time that there is another element that has not, as of yet, that I know of, been calculated that factors into felt recoil. That is ...... duration of powder burn. I have shot so many different loads in my life it would be impossible to remember and list them all. Many of them were duplicate loads as far as the elements listed .... velocity and weight of the ejecta. However, faster burning powders which deliver the same payload at the same velocity seem to have "sharper" recoil to me. Slower burning powders delivering the same payload at the same velocity seem to be less harsh .... more of a shove. All black powder loads I have ever fired seem to fall into this latter category. Recoil pads do the same thing .... spread the same free recoil out over a slightly longer duration, thus causing the shooter to feel less "kick".

One of those things that may never be quantified but, due to experience, I believe very strongly.

SRH

Certainly, different powders behind the same weight shot charge at the same velocity, all other things equal, can have a different felt recoil. But here we're talking about a specific shell (let's call it a Remington 1-ounce field load) that's fired in a factory chamber for 2-9/16 shells, and the next shell from the box is fired after the chamber is lengthened to 2-3/4". Supposedly the extended chamber will reduce recoil but how is that explained using Newton's Third Law?

[vaturkey]

Not sure how it relates do shotgun chambers, but when I reloaded rifle rounds (and I reloaded a lot years ago). More pressure generated directly meant more speed. Any powder you looked at in your reloading books had a correlating x amount of powder provides this speed and x plus amount of that same powder gave more speed, but with increasing amounts of pressure. What some folks did was look at the maximum speed one could achieve (because folks were speed driven) at a certain pressure to speed ratio and then back off a grain or two and check for flattened primers, sticky bolts etc., which would show you were generating too much pressure. Folks also figured out if you happened to load rifle rounds that were too long and they touched the grooves of the barrel, pressure would spike big time. There had to be a bit of distance to where the bullet started to accelerate before it hit the rifling.

What I don't know is if 2 3/4" shells are fired in a 2 1/2" chamber does the opening of the crimp hit the shorter chambers and cause increased pressure? I think from what I've read it does indeed. What I don't know is if that increased pressure result in additional speed for the shot headed out the barrel? More speed, more recoil even though the shell is essentially the same, but simply fired in a shorter chamber? Be curious what folks think. Be interesting to chronograph the same load fired in a Fox with shorter chambers and longer chambers and see what the results are.

[foxgun]

Be interesting to chronograph the same load fired in a Fox with shorter chambers and longer chambers and see what the results are.

That would be interesting! Seems like for valid results you would have to do the testing before and after chamber lengthening on the same barrel with the same ammo, don't think you could make any valid conclusion if you used 2 different barrels.