Redneck chamber depth gauge

[Ian Civco]

Pictured on top of one of my favorite books ever, is my "Redneck shotgun chamber depth gauge". Given that I am a thrifty person by nature, except that sometimes that has to go by the wayside when it comes to Parkers and other fine firearms, I am always looking for a thrifty solution to a problem.

I took a standard 2 3/4" 12 gauge shotgun shell and created a plug on the lathe, and inserted it into the 2 3/4" shell. In theory, it should work, except for I am unaware if the tolerances would be tight enough to always differentiate a shotgun rechambered for 2 3/4" versus one in its original 2 9/16" configuration. I don't currently have a known original shotgun with 2 9/16" chambers to try it on.

Here's the alternative: https://www.brownells.com/gunsmith-tools-supplies/measuring-tools/shotgun-chamber-gauges/shotgun-chamber-gauge-prod593.aspx

With something like this, virtually free is better, provided it works!

While we are at it, how does rechambering a vintage Parker shotgun affect value? I would think with a "shooter" it would enhance value, but a high grade nearly mint gun it would hurt value. How about your standard VH grades with above average condition, or even a DHE?

[Ronald Scott]

Pictured on top of one of my favorite books ever, is my "Redneck shotgun chamber depth gauge". Given that I am a thrifty person by nature, except that sometimes that has to go by the wayside when it comes to Parkers and other fine firearms, I am always looking for a thrifty solution to a problem.

I took a standard 2 3/4" 12 gauge shotgun shell and created a plug on the lathe, and inserted it into the 2 3/4" shell. In theory, it should work, except for I am unaware if the tolerances would be tight enough to always differentiate a shotgun rechambered for 2 3/4" versus one in its original 2 9/16" configuration. I don't currently have a known original shotgun with 2 9/16" chambers to try it on.

Here's the alternative: https://www.brownells.com/gunsmith-tools-supplies/measuring-tools/shotgun-chamber-gauges/shotgun-chamber-gauge-prod593.aspx

With something like this, virtually free is better, provided it works!

While we are at it, how does rechambering a vintage Parker shotgun affect value? I would think with a "shooter" it would enhance value, but a high grade nearly mint gun it would hurt value. How about your standard VH grades with above average condition, or even a DHE?

Why not use your lathe to turn a "plug" or rod (it could be wood if that's what you have) the correct diameter to fit into the chamber? Make it long enough so it protrudes out of the breach (just like the ones from Brownells). Stick it into the camber until it stops, mark the rod at the breach, and measure the length from the end of the rod to the mark.

The problem with using a shotgun shell is that it isn't long enough to measure a chamber that is longer than the shell.

[Ian Civco]

That certainly would be easy enough to do. What dimensions should I make it to? Such that, without question, it hangs up at 2 9/16" if that is the true depth or extends to 2 3/4 " if that is the true depth.

I guess what I had in mind is something that extends to 2 3/4" deep if that was truly the depth, or sticks out 3/16" (2 3/4 - 2 9/16 = 3/16) if the chamber depth remains the original 2 9/16".

[Ronald Scott]

Make it 6” long — stick it in the chamber until it stops then mark it at the breach. Remove the rod and measure the length from the end you inserted to the mark you made.

[Ian Civco]

I was implying diameter. I have a 2 3/4" Fox Sterlingworth I can use as a template, but I want to make it small enough so it doesn't get stuck and big enough so that it truly hangs up at 2 9/16".

[Gary Laudermilch]

This what I use. About as frugal as you can get but it works well. A 16 inserted into a 12 and a 28 inserted into a 20.

[Bill Jolliff]

Another cheapie method is just cut an empty hull off at the base, square it up, measure it and put the squared up end into the chamber til it stops and measure with a 6" machinists scale how far the hull went into the chamber and add that to the length of your squared off hull.

Works good for me.

https://i.imgur.com/ndWrRqB.jpg?1

[Daniel G Rainey]

A great book. enjoyed reading it.

[Dean Romig]

While we are at it, how does rechambering a vintage Parker shotgun affect value? I would think with a "shooter" it would enhance value, but a high grade nearly mint gun it would hurt value. How about your standard VH grades with above average condition, or even a DHE?


I would never, under any circumstances, alter the chambers of a good old double gun, regardless of whether it is collector condition or a just plain shooter. There is never a good reason to do so where another remedy would solve the perceived 'problem'.





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[Bill Murphy]

Dean has come around to my way of thinking, or maybe he always thought that way. Don't take steel away from a good set of barrels, for any reason.

[Dave Noreen]

All these gee-gaws are a waste of time and energy. Even commercial gauges are. The diameter at the mouth of the chambers where the forcing cones begin on these vintage doubles varies greatly, so getting an accurate length with any "gauge" is at best 50/50 chance.

My canned reply for this topic --

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.

[Drew Hause]

Relevant discussion of chambers and cones
http://parkerguns.org/forums/showthread.php?t=28515

More canned stuff ;)
There is an easy way to measure chamber length using a 3" x 5" index card, rolled lengthwise, and slid into the chamber. It will partially unroll and expand to the chamber diameter. Gently advance the card until it stops at the end of the chamber (where the forcing cone constriction starts), use a pencil to mark the card at the breech end of the barrel, and repeat the steps to see if it always comes to same spot. Then use a ruler to measure the length marked on the card.
The chamber must be clean, and it works best with a new 3” X 5” card.

The Parker Story has original factory engineering drawings, like this from Hunter Arms. No reason to guess the dimensions.

http://pic20.picturetrail.com:80/VOL1373/6511424/15234180/413842322.jpg