WALL THICKNESS IN CHAMBERS
 

I know this subject has been resurrected and flogged like a dead horse many times but I wanted some actual measurements and personal input from members with their own guns. I have a Hosford wall thickness gauge and have found some interesting and varied measurements in my own guns. For example, I have a Parker PT grade 12 gauge with twist barrels. The right tube at the front of the chamber measures .087 and 6" inches from the breech measures .055 The left tube measures .092 at the front and .060 at 6 inches from the breech. I have shot this gun with low pressure shells for years. Does anyone have similar measurements in the their own guns? Please share your info. Thanks!:)

I just measured my 12ga DH Damascus # 94555. I do not have a wall thickness gauge so I measure inside and outside and do the math. Right barrel at 4.125 " in is .202 & 6" in is .132 ,left barrel at 4.125 " in is .209 & 6" in is .134 . I have been hunting with this gun for 4 years using RST 1oz paper. Sorry forgot to divide by 2 . So it's .101 , .066 & .105 , .067

Thanks James. I think those numbers might be a bit high. Several people in the past that have measured that way without a gauge get really high numbers. A wall thickness gauge I think is a must as you can get inside near the ribs. Thank you for taking the time to measure!

Sorry, forget to divide by 2. I have added right numbers.

Ok, that makes sense. Those are good numbers. Your bores have probably not be honed or polished. Nice gun!

James, you didn't say what frame size your DH is, but I think your numbers are just about right for a 2 Frame gun.
Coming up with a reasonably valid number by halving the difference of the ID and OD, will only be reliable at the chamber, forcing cone and perhaps a few inches. Generally, you're more likely to find that, due to striking further down the barrels, the concentricity is less assured. I've seen differences of several thous between one side and another, or top and bottom, at the last 10" or so, then becoming more concentric around the beginning of the chokes.

The frame size is 1 1/2 , the barrels are original 26" and nothing has been done to them as far as I can tell.

In measuring two 1 1/2 frame guns, I find .096", and .092" at the forcing cones. Not a huge drop on two 1 frame guns.

I have 79355 a 0-frame sixteen with .064" and .066" at the front of the chambers, beginning of the forcing cones that were measured by Oscar Gaddy and he pronounced them as "probably safe to shoot with loads under about 7,500 p.s.i."

I've taken a bunch of grouse and a couple of woodcock (and about 50 rounds of skeet) with it using 2.5" RST Falcon Lites.





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My 12 ga 1 frame twist barrels were measured by Mr. Hosford utilizing his equipment. The wall thickness at the end of the chambers was .115 and at the end of the forcing cones .090. Minimum barrel wall thickness was .030 in both tubes.