20 gauge chamber length
 

I don't have any reference material on Parker guns so I'm hoping someone here would be kind enough to answer my question. I am looking at a 20 gauge Parker -- it has 2 1/2' chambers. Is there a specific time period that Parker switched to 2 3/4" chambers on their 20 gauge guns? If so is there also a serial number range that would indicate 2 1/2' vs 2 3/4"? Thanks, Ron

The Parker Story doesn't say when, but 2-1/2" was the standard 20ga chamber length at least until 1920.

It likely changed to 2 3/4" under Remington ownership - earlier, I'm sure, by special order.





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Thanks...

This is probably a dumb question but what exactly is a 2 1/2" chamber? Is the chamber exactly 2 1/2" long or is it chambered to fire 2 1/2" shells? I assume the latter -- so a 2 1/2" chamber is probably 2 3/4" long?

And as a followup, can a 2 1/2" chamber safely be lengthened to 2 3/4"? Pros and cons?

Chambers are measured from the breech surface of the barrels forward to the point where the taper of the forcing cone begins. If it measures 2.5” then you have 2 1/2” chambers.
On chambers with the tapered forcing cone, paper shells that open 1/8” longer than the chamber length were intended to be used. The extra 1/8” of shell length that opened into the cone was to provide a superior gas seal.

It is not advisable to lengthen the chambers on these old doubles. Not only do you destroy the value of the gun, unless wall thickness is very carefully measured, lenthhening chambers can compromise the integrity/safety of the barrels




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With Parker Bros. policy of holding chambers 1/8 inch shorter than the intended shell, many guns intended for the 2 1/2 inch 20-gauge shell actually have chambers about 2 3/8 inch to the forcing cone break. My 1930 vintage VH-Grade is so chambered.

From the 1890s onward, our North American ammunition companies offered paper 20-gauge NPEs and loaded shells in four lengths -- 2 1/2, 2 3/4, 2 7/8 and 3-inch. The "standard" 20-gauge shell was 2 1/2 inch and carried a maximum load of 2 1/4 drams of bulk smokeless powder or 18-grains of dense smokeless powder such as Infallible or Ballistite pushing 7/8 ounce of shot. Back in the day, our ammo companies didn't include the shell length on the box labels of "standard" length shells.

Attachment 74370

The 2 3/4 inch, and longer, shells could be had with a slightly hotter load of 2 1/2 drams of bulk smokeless powder or 20-grains of dense smokeless powder such as Infallible or Ballistite pushing the same 7/8 ounce of shot. The perceived advantage of the longer 2 7/8 and 3 inch shells was more/better wadding.


Attachment 74369

I have a 20 gauge built in 1916. The PGCA letter states the gun have 2 5/8" chambers.

Ken

How long are your barrels Ken?





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Dean,

The barrels are 28" and according to the letter the requested chokes were RH 40% and LH 60%.

Ken