Chamber length
 

How to tell or measure if your chamber has been lengthened? 12 ga. Gun was made with 2-1/2 chambers.

What sort of documentation do you have that says it was made with 2 1/2" chambers?

What year was it made? What gauge is it? Do you have a letter on it? What were the results of Parker Bros. test firing it?






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Made in 1908,,,12 ga.. bought used??? I cant remember what year they went to 2-3/4,, but this was made before that.....

Have you measured the chamber depth with a precision instrument?






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A precision measuring chamber gauge or even a machinist's scale is just the ticket for measuring your gun's chamber length. But, if you don't have either of those, a Po' Man's Chamber Gauge will do everything you need it to do.
http://parkerguns.org/forums/showthread.php?t=18161

Generally speaking a 1908 vintage 12-gauge Parker Bros. double would have had 2 5/8 inch chambers, intended for 2 3/4 inch shells.

At that time, the U.S. ammunition manufacturers offered loaded 12-gauge paper shells in 2 5/8, 2 3/4, 2 7/8 and 3-inch lengths. In the 1890s and early 1900s you could get up to 1 1/4 ounce loads in any of these length 12-gauge shells, but between about 1905 and 1908 they phased out offering 1 1/4 ounce loads in the 2 5/8 inch shells. From then on they only offered up to 1 1/8 ounce loads in the 2 5/8 inch case and one had to go to the 2 3/4 inch or longer shells for 1 1/4 ounce of shot.

All of the repeating shotguns being introduced in those days were made for 12-gauge 2 3/4 inch shells -- Winchester Model 1897, Remington Autoloading Shotgun, Remington Repeating Shotgun, J. Stevens Arms & Tool Co. No. 520, etc.

Parker chamber lengths from TPS:

8ga - 3 1/4" chambers for 3 1/4" shells.

10ga - 2 7/8" chambers for 2 7/8" shells.

12ga - 2 5/8" chambers for 2 3/4" shells.

Why the inconsistency?

How about for a 1907 16 ga VH?

Were the 8 and 10 gauge chambers cut for brass shells or paper?

The 2 5/8" chambers were for 2 3/4" paper shells, allowing for 1/8" of the paper shell to open into the cone for a superior gas seal.






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Sometimes people get all excited about chamber length. Tests demonstrate that chambers 1/8 shorter than actual expanded shell length result in a pressure increase of 3 to 5%.

The SAAMI standard for nominal expanded shell length of 2 3/4" is from 2 5/8" to 2 3/4".
Shells from some manufacturers consistently run toward the minimum.

Yup, low pressure shells in guns with chambers shorter than the shells are no big deal. I am much more interested in the loads in the shells than I am in the length of the chambers compared to the length of the shells. Measure the wall thickness if you are suspicious.

Here is the chamber depths and shell lengths from the Remington-era Parker specifications sheets reproduced on pages 163 to 167 of The Parker Story --

http://img.photobucket.com/albums/v3...smbznpfpi.jpeg

Chambers 1/8 inch shorter than the intended shell in 10-, 12-, 16- and 20-gauges and 1/16 inch short in 28-gauge and .410-bore.

I have owned 4 Short Tens, Parker, Remington, Lefever, from 1893 to 1905. The Parker from 1893 had square chambers, the others from 1900-1905 are tapered. All measured 2 7/8"

I still believe guns were chambered for a particular shell and marketing was used to tell the customer it could be used with another shell length and work just fine. I also think when it is difference of 1/8 inch collector/shooters fret too much about it in both directions (OMG my chambers are short, or OMG my chambers were lengthened). The focus should be on barrel wall thickness of each particular gun and shooting lower pressure loads when possible, but that is just me.

I've been reading this 1/8" shorter stuff for years. Agreed, early American side by sides were generally not marked for chamber length and gents have been shooting 2-3/4" paper shells in 2-5/8" 12-gauge chambers forever. So, what were American 12-gauge 2-5/8" paper shells intended for ..... 2-1/2" chambers? What American guns were those? By maker and model please ...... ?

Yup I know that 12-gauge 2-5/8" shells were generally loaded up to 1-1/8 ounce, and 1-1/4 ounce was put up in 2-3/4" shells. So why not just use 2-3/4" shells for everything as is done today? To save the trees by the amount of paper used for that extra 1/8" of hull length? :rotf:

Also, why did Savage routinely rechamber 12-gauge Foxes that were sent in for repair to 2-3/4" and reproof/stamp the barrels as such? If 2-5/8" chambers were intended for 2-3/4" shells, why not leave well enough alone?

Just some food for thought gents.

http://i1044.photobucket.com/albums/...pspizmdcar.jpg

I don't think there is any logical answer to these questions. The reasons for chamber length vs. shell length probably died along with the men who devised them.

Determining 'originality' may be the only good reason for measuring chambers these days, in view of the fact that none of us intentionally overload our old guns, either by length of cartridge or by the ballistics of the loads we use.






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The main ones I can think of were the Winchester Model 1893 and the Spencer pumps. Here is a fairly light 12-gauge Parker Bros. made for 2 5/8 inch shells (sorry I didn't keep track of the original poster of this picture) --

http://img.photobucket.com/albums/v3...psvugumfxe.jpg

I have seen record cards for Ansley H. Fox two barrel sets where the longer tighter choked set was ordered for 2 3/4 inch shells and the shorter more open choked barrels for 2 5/8 inch shells.

Probably lawyers!! That policy may have had more to do with 20-gauge guns originally chambered 2 3/8 inch intended for the 2 1/2 inch shells, and 16-gauge guns chambered 2 7/16 inch intended for the 2 9/16 inch shells.

Dave did the 2 5/8" chamber proceed the introduction of 2 3/4" shells?

The early 1-1/4 ounce 12-gauge loading (2-3/4") wasn't that popular before the introduction of progressive powders in the Super-X shell (1922) and its clones. That's because the earlier degressive burning powders like DuPont's Bulk and dense Ballistite and Infallible couldn't get all that shot moving in a hurry without deforming a large percentage of the pellets, and especially when restricted in a chamber that was 1/8" short. Hence it was known that the 2-5/8" 1-1/8 ounce load would perform about at par at distance, and with less recoil. I don't know about early Parkers but I've seen and measured many early Foxes in wildfowler configuration that have factory chambers measuring a full 2-3/4" - no doubt intended for what was then max long range performance with the period 1-1/4 ounce factory loads with degressive powders in 2-3/4" cases.

Regarding those Winchester 1893's and Spencer pump guns I have a hard time believing that 2-5/8" shells were being manufactured in quantity for a comparatively small number of them. And it would be nice to hear from someone who actually measured their chambers (or the ones ones in that Parker in the pic) to tell us if they are really 2-1/2" as per my earlier question.

Dave's comment on Savage lengthening 20 and 16 gauge chambers makes sense after small gauge shells were standardized at 2-3/4" but again, if 2-5/8" chambers were intended for 2-3/4" shells for that "tight gas seal", why was that done on 12-gauge guns? A rhetorical question gents .....

Generally I've only researched from about 1891 when I find Union Metallic Cartridge Co. beginning to offer factory loaded smokeless powder shotgun shells. Looking at an 1884 UMC catalogue I see them offering brass 12-gauge cases from 2 1/2 to 3 1/4 inch length and paper 12-gauge NPEs from 2 5/8 inch to 3 1/4 inch. Going even farther back to an 1880 catalogue they offered paper 12-gauge cases from 2 5/8 inch to 3 1/4 inch. I don't have access to anything from the 1870s that shows shotgun cases but 1869 the just offered 10- and 12-gauge brass cases and no mention of length.

Clearly Parker stated 2 5/8" chambers for 2 3/4" shells, which I think was a marketing ploy.

When did Parker's starting coming through with 2 3/4" inch chambers as a standard? I don't believe the plastic wad was invented until the 1950's, so the argument chambers were cut an 1/8" shorter for a better gas seal should have been valid right up until Remington stopped making the Parker Gun. My point Parker would never have had reason to chamber any 12ga gun non magnum gun longer than 2 5/8", but they did.

Question: I have a 12ga Parker that letters with 2 7/8" chambers circa 1917. Was the gun intended for 3" shells? I believe both 2 7/8" and 3" 12 gauge where avaliable at this time.

It is quite possible that the superintendent of the gun works, along with upper management, in an effort to simplify the operation and keep costs down, chose to begin chambering at least the 12 gauge guns at 2 3/4". Maybe they discovered that the supposed "improved performance" provided by a "better gas seal" wasn't significant enough to warrant anything shorter than 2 3/4". Who knows...? I think the reasoning behind all of these variations in chamber length died with the men who developed them.
Yes, they did want to make the finest shotgun on the market that would out-perform all the others, and they certainly can't be faulted for that - but times were tough in the 1930's and many things changed as a result.





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You can bet on it Craig!





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Or perhaps they were forced to adhere to SAAMI standards.

i know one thing for sure the old paper wad in a 2 1/2 inch 410 shell will pattern in a 3 inch chambered gun as it will in a 2 1/2 inch chchambered 410... just as a 2 3/4 inch 12shell will patern the same in a 3 1/2 inch gun as well as it will in a 2 3/4 inch chambered gun..with paper wads....charlie

I have a D grade hammerless with damascus barrels ordered in 1892 with 2 3/4" chambers as per Parker letter. Is that unusual for a gun of that era to be ordered with that chamber length? The gun was ordered by DuBray and it also specified 3 1/2lb. trigger pulls.

The ammunition companies were offering a lot of different length cases well before that time. The only UMC 1892 vintage paper I have access to is a price list and it doesn't mention anything about lengths. At that time they offered their 12-gauge smokeless powder loads in their SMOKELESS shell from 2 1/2 drams pushing 1 1/8 ounce of shot for $47.00 per thousand to 3 1/4 drams pushing 1 1/4 ounce of shot for $49.50 per thousand. If loaded in their higher brass TRAP shell an extra $5 per thousand. Their black powder NEW CLUB 12-gauge shells started at $25 per thousand.

Unfortunately we can't look into the mind of the customer and know if he wanted the gun to shoot, 2 3/4 inch shells or 2 7/8 inch shells? I do remember reading an magazine article about DuBray being on a trip through the south doing a lot of hunting with a 16-gauge using 2 7/8 inch shells.

Is there a difference in what was done when the records say "chamber 3-inch" or when they say "Chamber for 3" shells"? Would the first give the customer a 3-inch chamber and the second a 2 7/8 inch chamber?

We can certainly tie ourselves in knots over this chamber length stuff!!

Frank, even some of the early humpback auto guns had short chambers. A friend reloads for his at 2 9/16 - believe it's a 16ga. So yes, the shell manufactures would have made a number of factory shells what we now consider short.

The Browning A5 16-gauge was made for 2 9/16 inch shells up to WW-II, and our North American ammunition manufacturers continued to supply 16-gauge shells in the 2 9/16 inch length up to the early 1960s. The 12-gauge A5 was made for 2 3/4 inch shells from the get go as was the Remington Autoloading Shotgun later known as the Model11.

That is certainly not what writers, such as A.P. Curtis and others, said back in the day. The last Ithaca Gun Co. Flues period catalogue (1925) states -- "Unless otherwise ordered Ithaca 28 Gauge and 20 Gauge guns are chambered for the standard 2 1/2 inch shell, 16 Gauge and 12 Gauge for the standard 2 3/4 inch shell and 10 Gauge for the standard 2 7/8 inch shell. Longer chambers are furnished if ordered on new guns without extra charge, but it should be remembered that shells of standard length do not give quite as good results in chambers which are longer than the shells and it should be remembered that extra long shells are more expensive and it is much harder to find a dealer who carries extra long shells in stock."

I find that 2 3/4 inch pretty strange in the 16-gauge, because 2 9/16 was the standard 16-gauge shell, and all the NID period catalogues from 1926 through 1933 state that their 16-gauges are chambered for the 2 9/16 inch shell.

short 10 and shorter 10
 

Ok, I'v read these comments about the 1/8 inch variances, but how about shooting a 2 7/8 inch shell in my old Parker 10 chambered for 2 5/8 shells?

How about shooting 2 3/4 inch shells in a 20ga that has 2 1/2 chambers?@ #

i shoot 2 3/4 inch 20 ga shells in 3 of my 2 1/2 inch chambered parker guns with no problems...and please some of you go pattern your longer chambered guns and see if yall see any differance in your patterns..charlie

About thirty years ago I was shooting a lot of Doves with a 16-gauge 1928 vintage A.H. Fox Sterlingworth Ejector Field chambered 2 7/16 inch intended for 2 9/16 inch shells. I was using those wonderful compression formed 16-gauge 2 3/4 inch Winchester/Western Dove & Quail loads that the folks at Olin provided us for a few years. I didn't see any problems shooting those shells in the gun, but it really ironed the crimp memory out of those cases. When I shot them in my 1909 vintage Remington Arms Co. KE-Grade with full 2 9/16 inch chambers and more modern 2 3/4 inch chambered pumps and autos the crimp memory was great and to this day I get better reloads from the hulls shot in longer chambers then those originally shot in that Fox.

Indeed sir. I've used 2 3/4 inch hulls/cartridges in 12, 16, 20 and 28 bore guns for years. Thousands upon thousands of rounds, too. Velocities are around 1150 fps. NEVER a problem. And the hulls come out looking totally normal.

Consider that the forcing cone accommodates an extra 1/8 to 1/4 inch of case material with no issues...

So I'm looking at a 1915 catalogue from the Edw. K. Tryon Company, the large, well known sporting goods distributor in Phila. On just one page there are (33) factory-loaded 12-gauge "high brass" 2-5/8" shells listed, with respected trade names like: Leader, Arrow, Ajax. The named shells were loaded by Winchester, U.M.C. and U.S Cartridge with Bulk and L&R dense smokeless powders.

Wow! There must have been many guns out there with 2-1/2" chambers intended for 2-5/8" shells ..... as per that 1/8" short convention we read about so often. :rotf:

If wooden dowel fits in between 2.86" to 3.1" then its redone to 2-3/4".
If forcing cone look elongated that may mean same, since a lot of time gunsmiths use elongating forcing cone reamers to do that.

I would not trust a wooden dowel to measure chamber length. I would only use an instrument designed for the purpose and that would measure in thousandths of an inch.





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I believe there'll be .005 tapper per inch, then when you hit the forcing cone there'll be a very fast tapper.