Barrel Wall Thickness

[Drew Hause]

The Field March 7, 1891 Vol 77:325
http://books.google.com/books?id=inQ...=0#PPA9-IA6,M1



UK Working Standards recomended minimum wall thickness measured 18" from the barrel breech from Double Gun Classics p. 56, Vol. 1, No. 4 Jan-Feb, 2006:
2 1/2" 12g- .028
2 3/4" 12g- .032
Re-proof recomended minimum- .024

The Hunter's Encyclopedia from the German proof house: minimal wall thickness at end of chamber, regardless of length, for 12, 16 & 20 gauge guns should be 2.3mm (.0906") for 'ordinary good steel' or 2.1mm (.0827") if a 'Special Steel' was used. For the 24 & 28 gauges, due to their higher pressures, 2.4mm (.0945") was recommended.
Minimal wall of .6mm (.0236") was recomended in the "forward third" of the barrel.

[Bindlestiff]

Originally Posted by Drew Hause

The Field March 7, 1891 Vol 77:325
http://books.google.com/books?id=inQ...=0#PPA9-IA6,M1



UK Working Standards recomended minimum wall thickness measured 18" from the barrel breech from Double Gun Classics p. 56, Vol. 1, No. 4 Jan-Feb, 2006:
2 1/2" 12g- .028
2 3/4" 12g- .032
Re-proof recomended minimum- .024

The Hunter's Encyclopedia from the German proof house: minimal wall thickness at end of chamber, regardless of length, for 12, 16 & 20 gauge guns should be 2.3mm (.0906") for 'ordinary good steel' or 2.1mm (.0827") if a 'Special Steel' was used. For the 24 & 28 gauges, due to their higher pressures, 2.4mm (.0945") was recommended.
Minimal wall of .6mm (.0236") was recomended in the "forward third" of the barrel.

Thanks Drew, I incorporated this information and some of the other comments to improve this FAQ.

Thank all for your input, it helped too.

[Twice Shooter]

Dr. Drew,

Please check your PM. Tom

[Jim Kucaba]

Originally Posted by Robin Lewis

Thanks Drew, I incorporated this information and some of the other comments to improve this FAQ.

Thank all for your input, it helped too.

Robin ... What a great illustration ! ... I hope everyone prints several copies for future reference ... THANKS !

Jim Kucaba ... AriZOOna Cactus Patch ... Email: JimKucaba@aol.com

[Jean-Paul Lavalleye]

Following up on Drew Hause's above post regarding The Hunter's Encyclopedia from the German proof house, is there data of actual measurements, current or old, of Parker barrels minimal wall thickness at end of chamber, regardless of length, for 12, 16, 20 & 28 gauge guns?

I currently own three Parkers on which I've made this measurement using Hosford and Co. barrel wall thickness gauge. The chamber minimum wall thickness data for these is as follows:

1.) BH 12b. on a no. 1 frame, R ≥ 0.088, L ≥ 0.094 (Damascus barrels)
2.) GH 20b. on an 0 fame, R ≥ 0.100, L ≥ 0.092 (Damascus barrels)
3.) DHE 28b. on an 0 frame, R ≥ 0.084, L ≥ 0.076 (Titanic steel barrels).

All of these have been shot for many many years (not by me) and measure up well in terms of min wall thickness and bore diameters. Kirk Merrington tells me that, in his experience, Parkers and other American guns tend to have wall thickness at end of chamber that are considerably less than found on English or German guns (in the 0.080"-ish range). Yet this does not seem to be problematic. The Sherman Bell articles of a few years, in the Double Gun J., regarding the strength of Damascus barrels would seem to support this conclusion.

Is there data somewhere that would show how low you can safely go with these thicknesses (or how low Parker went when they were making these guns)? I am currently looking at a 16b. Parker on an 0 frame where that minimum thickness (for a 2.5" chamber) is 0.068" on one chamber and 0.071" on the other, with all other measurement being fine; bores at 0.667, min barrel wall thickness at 0.030." This gun has very obviously been shot quite a lot. Is it safe?

[Double Lab]

JP,
I looked at that 16b you are referring to on Sat. and without any way of measuring other than by my eye they looked just fine to me. Your measurements of the BWT seem to me to be quite acceptable and the bore diameter is well within specs. I would have no problems shooting it with low pressure handloads or RST loads. Have the barrels been blued? I did'nt examine them that closely but that is a sweet gun. I was really interested in the smallbore P grade with twist barrels.

Daryl