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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