doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Damascus Pitting

Drew,
Some older Damascus barrels have the proof marks stamped on the barrel tube rather than on the barrel flats[Some suggest that at one period of time the barrel tube was the location used on U.K. guns intended for Export]. My point is; that the depth of indentation of some proof marks is greater than majority of barrel pits encountered and clearly act as potential stress raisers.Stamping proof marks requires a heavy blow,this too could cause cracks to develope.Have you seen any examples of damascus barrel failure attributable /originating at the site of the proof marks ?

I have not Roy. I think Bro. Larry made the point that barrel engraving can be fairly deep also, but at the breech with greater wall thickness. Rocketman or Chuck H explained that internal defects are subject to much greater 'hoop stress'. As to my comprehension thereof, they might as well have been speaking Urdu however

The few fractures that I've seen appear to be at dents



or where someone attempted to repair a bulge



This might work

Difference between a proof stamping and a pit is that in a stamping the steel is displaced but sound. With a pit, the metal has disappeared because of rot and often spreads below like cancer. Don't know how much difference this makes in structural weakness though.

I have told this before but has been some time so will run it again. Some years back i purchased a "Parts" condition Lefever H grade with 30" Twist bbls. 14" up from the breech on the side of the left bbl was a "Crack". This crack had the appearence as if the bbl had been hit on a sharp corner of some object which had dented it in. It was apparently then fired in this condition resulting in the crack. One side of the crack was caved inward & the opposite side was flared outward leaving a readily visible crack which you could look through & see the opposite side of the bore.
Any way I put the expanding dent plug under it & raised the dented in side & hammered down the flared side which closed the crack till it was virtually invisable. I then proceded to place it in the "Firestone" proof bench & fire several rounds through via a string from behind a hefty Black Walnut tree. Started with factory 3DE-1 1/8OZ loads, then went to factory Rem Express 3 3/4DE-1�OZ loads. I had some handloads which were an approximate 3�DE-1 3/8OZ so fired a few of those also. Through all of this the crack did not re-open, no smudge was visable on the exterior of the bbl, in fact there were no signs at all it was not a totally solid barrel. I do not shoot it of course & so far haven't needed any of its parts so it sits still in storage.
I can locate he crack "Because" I know where it is. Anyone else would be hard put to find it. The bores are also heavily pitted, the stock had to be taped up to hold together for the firing & one sear is worn so is very touchy, wouldn't trust it to carry, so it is a parts gun besides just the bbl crack. I truly expected that crack to open back up on firing though so was totally surprised when it didn't. The crack did run along with the spiral of the twist & was at least �" in length, maybe as much as 3/8" right out on the left side of the bbl..

Miller: here's an H Grade Lefever with "Best London Twist" or "Damascus Twist" with a fracture along weld line

The gun in question here is an early Lefever F grade (so Damascus, not twist). There are no visible defects on the outside. Just the commonly seen pits resulting from black powder and a lack of rigorous cleaning. The barrels have not been honed or otherwise altered.
Right now I need my fingers to work the endoscopes that are the tools of my trade.
Better to:
1. Hang it on the wall or put it in the safe?
2. Have it honed smooth and see what the wall thickness is then. Shoot if sufficient. Hang it up if the amount of honing required to remove the pits results in too thin barrels?
3. Shoot it with low pressure RST ammo and quit being paranoid?

Bob, only you can or should make that call. Me? If the pits aren't gaping holes in the bore, especially in the first 8 or 10 inches, I'd buy the RST's and have at it. To ease your mind perhaps you should remotely fire a half dozen rounds. Tie it to a tire or something like that and pull a string.

Bro. Bob: Since the thread began, I've been looking through the works of the Greener's and others here https://docs.google.com/View?id=dfg2hmx7_308gtmpgfc6 and can't find any specific statement regarding the justification for honing pitted barrels. There must be a reason so many fine British SxSs (now) have thin walls however.
I vote 2.

Drew and Joe,
Both of you offer sage advice. Unfortunately I am not in a position to tie it to a tire and test it. Therefore, I will send it to Keith Kearcher and have it honed and ask Keith to measure it after honing. The gun is in the possession of a new Lefever enthusiast who wants to shoot it along with his son at the Uncle Dan Cup in June. I would feel dreadful if there were an adverse outcome. There are always other guns. However, there aren't a whole lot of original Lefevers.

Just my two cents, if the bores have never been honed and are the original bores with pitting, removing the pitts is going to do what? It is not going to make it any safer with honed bores and less metal now.
Shoot it with low pressure low velocity loads, like stated, RST's.