BBL Thickness

[Mike Franzen]

What would be considered an acceptable bbl thickness for a PB 16 ga, damascus on a 0 frame with 26" bbls?

[OH Osthaus]

Gauge and frame would only give you a rough idea of where it started.

A search will find this topic discussed many times. Along with what was the thinnest walls that are factory original.

The thinnest damascus I shoot measures just above 30 thousands. Way more than anyone's recomened minimum.

[AmarilloMike]

It depends on the distance from the breech.

I have a rule of thumb for Damascus - minimum wall thickness of .025" (25 thousandths). But that would be too thin at the muzzle end of the forcing cones. But perfectly acceptable in the last 12 inches of the muzzle end. I have been told by barrelsmiths that 25 thousandths is the minimum they need to work with to repair a dent. So the .025" minimum in the forward end of the barrel is not about barrel bursts but about dent repairability.

Best,

Mike

[Dean Romig]

Some say more, some say less, but 25 thou. is a good safe figure. I would even suggest, with perfectly sound barrels, the forward half of the barrel length could be 25 thou. Pressures drop off radically within the first 10 - 12 inches from the breech.

[ed good]

the other number that comes to mind is 90 thousands in front of the chambers.

[AmarilloMike]

I copied the measurments below from a post I made on the DoubleGun BBS a few years ago.

http://www.doublegunshop.com/forums/...=224972&page=3

"I sure have a lot of doubles with original chambers and forcing cones with wall thicknesses way below .100" at the end of the chamber.

Fox A grade 16ga, 26" barrels, 2-7/16" chamber, 0.085" and 0.086" minimum wall thickness at the end of the chambers, .734" and .734" diameter at the end of the chambers, 5/8" long forcing cones, #4 barrels, gun weighs 5lbs 9oz, serial 302XXX.

Parker VH O Frame 16ga, 28" steel barrels, serial 134XXX, 2-9/16" chamber, .082" and 0.085" minimum wall thickness at the end of the chambers, 0.730" and 0.732" end chamber diameters, 3lbs 2oz unstruck barrel weight, gun weighs 5lbs 14oz.

Fox XE 16ga, 30" barrels, serial 301xxx, .072" and .080" minimum wall at chamber ends, 2-7/16" chambers, .733" and .733" end chamber diameters, gun weighs 6lbs 3oz

Parker DHE 16ga, 32" steel barrels, serial 212XXX, 0.090" and 0.092" minimum wall thickness at chamber ends, 2-9/16" chambers, .735" and .736" diameter at chamber ends, barrel unstruck barrel weight 3lbs 11oz, gun weighs 7lbs 4oz.

Lefever H grade 16 gauge, 28" twist barrels, .090" and .092" minimum wall thickness at chamber ends, 2-5/8" chambers, .729" and .728" diameter at chamber ends. Gun weighs 6lbs 4oz

Ithaca Flues Grade 4E 16 gauge, 28" Krupp fluid steel barrels, 0.091" and 0.092" minimum wall thickness at the end of 2-5/8" chambers, daimeters of .728" and .730" at the end of the chambers, gun weighs 6lbs 6ounces.

Parker DH 12 bore, 28" Damascus barrels, 1 frame, .086" and .090" minimum wall thickness at end of the 2-5/8" chambers, gun weighs 6lbs 14oz. Serial #84XXX, My Skeets gauges are incapable of measuring the diameters at the end of the chamber.

Bissel Birmingham boxlock, 20 gauge, 25" steel barrels, made in the 1920s, .084" and .092" minimum wall thickness at the chamber ends, 2-1/2" chambers.

My Skeets gauges are in capable of measuring the diameters at the end of the chamber."

[Dean Romig]

Without appearing to condone the shooting of such thin-walled guns, I will say that I have an 1893 16 ga. 0-frame GH(e) with Damascus barrels that measure, at the front of the chamber where the forcing cones begin, .066" and .064" that I used to shoot for years as my "go to" grouse gun.

I have the letter from Oscar Gaddy when I sent him the barrels for his inspection where he states they are "probably okay to shoot using light loads of 7,500 p.s.i. or less." and he's the one who provided these measurements for me.

Again, I do NOT condone anyone else shooting any gun with such measurements.

[AmarilloMike]

A few months ago I had a Remington/Parker VHE 28 gauge on approval. I returned it because the MWT of the chambers was in the range of 65 thousandths. I believe they left the factory that way and that thousand of rounds of modern 28 gauge shells had been fired in them.

[Dean Romig]

And you refused it??

[AmarilloMike]

Yes. I worried that if I kept it and then decided to sell it it would be hard to sell because of the chamber wall thicknesses. I might be wrong about the difficulty of selling it though.

Best,

Mike