Damascus barrel question

[qkdraw44]

I have a 12ga side x side Damascus barrel shotgun. is it safe to use chamber inserts and fire 20ga or 410 shells in it?

[Ballistics in Scotland]

Do you mean with modern smokeless cartridges? In this case the answer has to be "maybe" and "insufficient data available", with little chance of the .410 doing any harm.

The usual principle gunmakers work on is that barrel and action should have equal ability to withstand pressure. There is no benefit in one being able to stand pressure under which the other has given way. This would be all very fine and well if guns stayed exactly the way they were built, but they don't. Normally the barrel is the one most likely to lose strength in an old gun, but it is mainly the action body that you have to consider.

Damascus shotguns cover a very wide range of things. Some early early ones are bar in wood, with wood surrounding most of the front end of the sidelock, and very little metal in the action body. They often have very thin barrel walls, which most likely aren't the point of least resistance when chamber inserts are used.

Others, by the 1890s or so, had action bodies which, although of case-hardened plain steel, are as strong as a modern smokeless action needs to be. This is accompanied by barrels which are stoutly made, so if they haven't been unwisely rebored to remove pitting, or had excessively deep dents raised, they may stand smokeless powder proof in countries where this is mandatory. Damascus isn't as strong a metal as modern shotgun barrel steels, but it isn't bad, and two factors mean the forward parts of most barrels are much thicker than they need be to resist gas pressure alone. One is that thinner metal will dent very easily, and the other is that recoil imposes a limit on how light it is desirable for a gun to be.

A back-action gun, which doesn't require removal of metal from the action to accommodate its mainspring, is stronger than an ordinary sidelock, and both are stronger than a boxlock, which has more metal cut away to house the lock parts, and is very hard to design without a weakening screw-hole on the line of maximum weakness, which runs downwards from the bottom of the breech-face.

The peak pressure in a shotgun is developed when the charge is exiting or immediately in front of the chamber. At this point your barrel would be reinforced by the thickness of the chamber insert - and most reinforced is this is of steel, rather than aluminium alloy like some. When the charge exits into the full-diameter barrel, gases are free to pass around the undersize wad and shot column. I think the chances of a barrel burst are low, if it is of reasonable strength and condition.

But a 20ga round, which has built up full pressure in the insert, will thrust on the breech face just as much as that cartridge would in any other shotgun. 20ga in an action dimensioned for 12ga works for you, but quality of metal and possible deterioration work against you. I would want to be very sure of the quality and condition of the gun before I would try that.

[elk hunter]

I'll say possibly. The overall condition of the shotgun is important. A loose, rattling gun is just that irregardless of the type of barrels it wears. Also most Damascus shotguns were made in the black powder era and because of design and materials aren't as strong as the later ones. I've seen several of them with stretched and cracked frames from shooting modern ammunition. Of the many hundreds of them I've examined seldom are the barrels a point of failure.

If you can find someone with knowledge and experience with this type of shotgun they should be able to advise you if it is possible to shoot it with sub-bore inserts or even in the original gauge with proper ammunition. Most gunsmiths today have no real knowledge or experience with damascus barrels and will automatically say they are dangerous and not to shoot them. If they are all that dangerous why are the British still re-proving them for proper modern ammunition.

I hope yours is a quality shotgun in good condition and that you can enjoy shooting it.

[country gent]

The biggest issue with the damascus barrels is thier integrety. Damascus barrels were made by hammer welding 3-4 blades or wires around an mandrel forming the barrel. This process depended alot on the skill the maker and his knowledge along with the actuual steel. Most of these had small inclusions cracks or partial weld sections small and when new not an issue. Since most of these seen use with black powder crossive primers and other issues including age now. These small inclusions would hold the corrosive fouling slowly getting bigger and weaker as time went along. I know of very few that recomend firing damascus barrels even with black powder loads. Another thing to find out on these guns is chambers were cut in 12 gauge at 2 1/2, and 2 5/8 instead todays standard of 2 3/4.

[Ballistics in Scotland]

Any number of people recommend the use of black powder loads in a sound Damascus gun which has been carefully checked for condition. Some late ones were proved for smokeless powder, or made, before a separate proof was introduced, in the knowledge that it would be used. It all comes down to the type of gun, and its condition.

[Outpost75]

Good quality insert tubes will stand the pressure of modern smokeless shotloads by themselves. I used to have a cased 16-bore Alex Henry underlever sidelock hammer gun with Damascus barrels for which I had full length 28-ga. Briley tubes fitted and I hunted birds with it for years until selling it to a fellow who wanted a Cape Gun and he had the left barrel lined and set up as a .45-70, keeping the other barrel as a 28-bore with choice of Briley tubes in either 1/4 choke or 1/2 choke.

I do not recommend shooting Damascus barrels even with black powder unless they have been magnetic particle inspected using the wet method with continuous circular magnetization. If they pass that I would shoot them with black powder only. NO WAY would I shoot smokeless loads of any description in them.

[M-Tecs]

Providing the gun locks up fine no issues at all. As Outpost stated the insert tubes withstand the pressure by themselves. It's a 12 gauge frame and the smaller area of the 20 and 410 will have less bolt thrust. Until the 3 1/2" mags the SAAMI spec for 12 gauge was 11,500 psi. Heavy real black powder loads hit 9,500 psi but 6,000 psi is more normal for black powder loads.

Interesting read here http://www.shotgunworld.com/bbs/viewtopic.php?f=13&t=259371

[Ballistics in Scotland]

Providing the gun locks up fine no issues at all. As Outpost stated the insert tubes withstand the pressure by themselves. It's a 12 gauge frame and the smaller area of the 20 and 410 will have less bolt thrust. Until the 3 1/2" mags the SAAMI spec for 12 gauge was 11,500 psi. Heavy real black powder loads hit 9,500 psi but 6,000 psi is more normal for black powder loads.

Interesting read here http://www.shotgunworld.com/bbs/viewtopic.php?f=13&t=259371

Provided that some, perhaps most guns lock up fine, yes. As I said, some action bodies for damascus guns are very frail. I have a French 16ga dated 1874 which is of very good quality and fits me like the proverbial thing, which I don't fancy using even with black powder. Others are just the type that the best English makers are using still.

Outpost's Henry probably had the rotary double-bite lever, which is among the strongest kinds of action, and lingered on big game rifles after it was superseded on others. Many held it worth requiring that extra movement when something dangerous was coming at you. But it is wrong to think this is because it draws the barrels down very firmly onto the action table. The tendency for pressure to swivel the breech open is very low, like trying to push a door open with pressure on its rear edge, where the hinges are. What counts is the force pushing the standing breech back from the cartridge heads, and the rotary lever is stronger because it doesn't remove metal at the natural point of action bar fracture, as the sliding Purdey bolt of the ordinary snap-action does.

Rear barrel extensions can be useful too. The common doll's head extension is often said (especially by Greener, it being Westley Richards's great selling point) to be completely useless. Well, not entirely, for it is unlikely to prevent an action bar fracture. but it increases your chances of walking away afterwards. But the best is the Greener "Treble Wedge-fast" extension, with a round transverse hole and bolt rather than square, so that it can be reamed larger to compensate for wear. Here is mine, in cheaper form than Greener's:

158401

The first two in "treble" were the two points at which the Purdey bolt engages with the lumps under the barrel. In fact one rather than two there, as in a Charles Daley Prussian hammer gun of mine, makes no difference to strength, and very little to wear resistance. Pieper in Belgium made a four-bite locking system, number four being a slot in the rear of the Greener extension, open to the rear. This one did no good of any kind.

I am sure there are early Henry shotguns that would make a good .450 rifle, and no doubt Outpost's friend exercised due discrimination. You might even find the barrels well enough regulated for hunting purposes as a double rifle. I think firing a proven ball load in the unmodified barrel would give clear enough information whether to stop with a Cape gun or proceed to stage 2. But there are modern .45-70 loads which would be unwise to fire in such a rifle, and plenty of people with them around ranges, or who might own the rifle in generations to come. I think there was a lot to be said for chambering it for a round seldome so loaded, like .43 Spanish or .45-60WCF.

British pressure specifications, often three to four tons even for smokeless, shouldn't be taken as directly comparable with true psi readings. But you are right that there was very little difference in the peak pressure of black powder and the usual game-gun pressures, which weren't worth increasing before plastic shot-sleeve wads reduced the chance of a blown pattern or shot fusing together. Going to a larger gauge to get more range or killing power, debatable now, was certainly the right thing then.

The rash of blown up guns reported in your article aren't necessarily something that would apply nowadays. It was simply difficult to make smokeless powders accurately to a specific standard of speed and power. In fact it still is. Large-scale commercial loaders and arsenals simply buy tons at a time, test it, and adjust the load to suit. Manufacturers who sell canister powders for the home reloader test it and if necessary reclassify a powder as something else, mix it if grain size and specific gravity prove it not to separate out in transit, or return it to the extrusion and granulating process. Of course the customer pays for those costs.

[218bee]

I shoot skeet and sporting clays with a group who all shoot side by sides. I have 2 damascus barreled guns and others use them also.
I have seen a few that guys had "tubed" and they work ok. However as stated above all guns are different. Another thing to think about is the weight and balance can be thrown off or feel "weird". A friend tubed his modern Win 23 with 410 tubes, and once he tried it, hated it as for a 410 it was unnecessarily heavy.

As an aside you CAN use smokeless powder in Damascus barreled guns if you use PROPER loads. AND GOOD barrels.
When IMR was still making SR7625 we found this load on their website load data....12ga. AA plastic hulls, win209 primer, Claybuster CB1100-12 wads, 7/8 oz shot, and 24.6gr of IMR SR7625. Dont remember exactly what the stated psi was but it was below 5000 psi. I believe this is equal to or less than an older 3 dram load of BP pushing 1 1/8 or 1 1/4 oz of shot. Once my few pounds of SR7625 run out, I do not know if I can find another smokeless load with such low pressure and good performance. I believe it was listed at 1100fps. We all shoot this and it works very well. ALL our Damascus guns are in good shape, no rust, no pits, and function well.
I was told a "pit" either inside or outside of the barrel on Damascus can be the "tip of the iceberg", you dont know how much rust or rot lies above/below that pit.
I value my eyes, hands, and guns too much to take a chance shooting a "questionable" gun.

Sorry if I hijacked thread.

[218bee]

Another item to keep in mind is that the diminutive 410 actually operates at a higher pressure than most 12ga target loads.
Typical target loads for a 12ga run around 9000 - 10000psi whereas a 410 2 1/2in shell target load can be 11000 - 12000 psi.

[David todd]

In my experience ( about 30 years now) using vintage guns for hunting and shooting,actual recoil is harder in old guns not chamber pressure.
thus us because of the old wood stocks shrinking, etc.
A low recoil smokeless round is an excellent choice , but if the gun is sound mechanically , there is no reason not to shoot it with inserts.
my 1878 Westley Richards 12 bore was restored for me a few years back by a 'smith who does vintage restorations , and he confirmed my thoughts .
I often shoot it with 20 and 28 gauge inserts with no issues and it hasn't loosened up in the 15 years that I have shot it .
I shoot it almost every weekend in the summer and it is my main pheasant gun
David

[Cap'n Morgan]

I shoot my old English damascus barreled shotgun with 7/8 ounce sub-sonic loads (steel shot - can't use anything else over here) - Very mild recoil.

<Bragging warning> On a really good day I can bag 20 out of 25 in international skeet with the old gun :-P.

[griffiga]

I have an LC Smith double barrel hammer gun with Damascus bbs and I have fired it a lot, mainly with black powder loads (75 grains FFG and 1 1/8 oz shot) and it seems to do just fine. I have also shot a number of low brass target/trap loads (usually the 1 oz shot loads) which actually seem to kick a bit less than the black powder. The gun is tight and in pretty good shape. I would have a gunsmith check it for you first before shooting it. Damascus bbls are strong if they have been taken care of, but inattention over the years can let rust work it's way into it.