The Making of a Spiral Welded Damascus Gun Barrel

[Vikram]

This is an outstanding effort by Steve Culver.It just boggles the mind at the amount of effort involved in the making of a Damascus gun barrel.


[youtube][/youtube]


If you go to page-21 on this e-magazine,Sporting Shot#22, you can read the description and see the photos.

http://bluetoad.com/publication/?m=18740&l=1


You can find more about Steve Culver's work on his website.

http://www.culverart.com/


Best-
Vikram

[Grumpy]

Really interesting - good one Vikram !
Thanks.

[timmy]

The amount of work in something like this is incredible. I can only imagine the effort needed to make up a double barrel shotgun. It's no wonder that different methods were developed for barrel making, as this would be extremely expensive to make today.

The old Damascus shotguns were a drag on the market years back, when I was a young man in Montana. One fellow in town, however, developed a unique use for them, as they were not considered safe for smokeless loads. He used a damascus barreled LC Smith, usually considered the cheap ugly duckling of American side locks, but which are known for their strong rotary bolt lockup. He machined a pair of rifle barrels to fit into the 12 gauge bores, making each slightly off-center at the breech end. Then, after inserting them in the damascus barrels, he was able to fire and rotate them until he got his convergence point. The final part was to silver solder the rifle liners into the damascus bores, and the fellow had a damascus barreled .45-70 double rifle.

There is nothing like the looks of these barrels, and thanks Vikram, for giving a better appreciation of the work, craftsmanship, and artistry that went into making those fine old guns!

[Grumpy]

Somewhere on Youtube there`s ( or used to be ) a video of tribesmen in Afghanistan or Pakistan making a simple twist damascus barrel using a charcoal forge and hammers - also interesting but not as involved as this.
I`ve lengthened the chambers to 2 3/4" and then had the guns nitro proved on literally dozens of shotguns with damascus barrels. If the barrels are of good quality and in good order they are plenty strong enough for nitro loads.
One of the strangest looking shotguns I ever saw was a Sidelock ejector which originally had nice London twist barrels but had been sleeved with steel tubes. The damascus stubs had been etched and browned to really show off the pattern and then a gold spacer - a couple of mm wide - was placed between the stubs and the new steel tubes which were blacked. It looked very showy but decidely different.

[Vikram]

Grumpy and Tim, glad you liked the video.

You can see the barrel put to good use here.

http://www.hallowellco.com/other.htm

Dr.Drew Hause is probably the best authority on Damascus gun barrels to my knowledge.The sheer volume of information he has accumulated is really commendable.Links to his website are given below.

https://sites.google.com/a/damascusknow ... m/www/home

http://www.damascus-barrels.com/index.html

https://docs.google.com/document/d/1jQP ... edit?pli=1

[timmy]

[quote="Grumpy"I`ve lengthened the chambers to 2 3/4" and then had the guns nitro proved on literally dozens of shotguns with damascus barrels. If the barrels are of good quality and in good order they are plenty strong enough for nitro loads.[/quote]

Relatively recently, people have taken a second look at Damascus barrels and made the same point you are making here, Grumpy.

However, when I was young here in the USA, every box of shotgun shells that were sold had dire warnings printed on them, warning the buyer not to use the load in shotguns with Damascus barrels.

Right or wrong, nobody did that I knew of.

Vikram, thanks for those links. I will enjoy perusing them.

[herb]

Very nice, the amount of work is incredible. I have gained a new appreciation for my Greener with Damascus barrel.

Thanks Vikram for the links.

Herb

[Grumpy]

I can remember magazine articles - not so long ago - discussing the beauty of good damascus barrels but warning that the guns should never be used - not even with the `original` black powder loads. It seems to have completely escaped the notice of those writers that thousands of guns with damascus barrels were nitro proved when new. There has obviously been a revision of opinion that started to take place about twenty years ago because a very large number of damascus barrelled guns have gone to the US.

[TwoRivers]

I have a Lefever double with damascus barrels, taper-bored, that the previous owner, an ardent upland game hunter and skeet shooter, put over 22,000 smokeless shells through after he acquired it used. He was the kind of fellow who kept records of all his shooting. It produces beautifully even patterns, about 1/4 choke equivalent.

[Kittu]

hi sir
is it safe to fird modern loads trough damacuss barrel.as i hearead sherman bell blew a damacuss barrel at 30000 psi.in inida we have around 9000 psi in 12,gauage.is it safe to fire iof catrtides in damascus barrelle?

[Grumpy]

It depends upon the condition of the barrels. If they are in good condition with no pitting - or only shallow pitting - the wall thicknesses are adequate and there`s no delamination then damascus barrels should be fine with nitro loads .... normal nitro loads that is, not magnum loads.
30,000 PSI is WELL above any proof pressure for a 12-bore .... even the 12-Bore 3 1/2" magnum. I`m not surprised that he blew up a damascus barrel with that pressure ! If the 30,000 psi is a typo and the figure should actually be 3,000 psi then the barrel was obviously damaged.
Standard 12-Bore nitro proof is 850 bar - which is 12,328 psi. 850 bar is the proof that a damascus barreled gun would be subjected to.
If your damascus barrels are in good condition as detailed above then they should be safe to use with `normal` nitro loads. If they are not in good condition it would be foolish to use nitro cartridges.

[Kittu]

sir
its not typo its 30000 psi.he tested both damascuss barrels and fluid steel barrels.both were blown at 30000 psi
his article was published in doubleguns jounral some years back i dont have access to magzine.i have read about
this on internet.may be on nitroexpress.com i cant remember now.standard 12 gauge ammo in india is loaded with
pressure of 54mpa that converts into 7832 psi
http://ofbindia.gov.in/products/data/am ... /sc/16.htm

[TC]

Great post Vikram.
Luckily we still have quite a few shotguns with damascus barrels in India.

Thanks

TC

[Grumpy]

Ashokgodara, I was unaware of the Sherman Bell articles but have discovered that they were published in the Double Gun Journal and found the following from a post by Bob S in a Shotgun World forum, Aug 31 2011.


"Vol. 10, Issue 2, Summer, 1999, “Finding Out For Myself” Part I

Sherman tested low-pressure Smokeless loads as an alternative to Blackpowder loads, e.g., a load based on one from the Lyman Shotshell Handbook: Federal Paper hulls, 1 1/8 Oz Shot, Federal 12C1 plastic wads, Winchester 209 Primers with 25 grains of SR 7625 powder, yielded 6,300 PSI and 1,123 FPS. Many loads that he tested closely duplicated BP pressures and velocities.

Vol. 10, Issue 4, Winter, 1999, “Finding Out For Myself” Part II

A SxS Parker with Damascus Barrels was tested till destruction. The gun was described as a ‘Wall-Hanger’ having pitting throughout both barrels but none dangerously deep with several small dents near the muzzle.

The loads were started at 1,254 FPS and 11,900 PSI (400 PSI above the modern SAMMI maximum pressure for a 12 Ga.). The loads were increased in approximately 2,000-5,000 PSI increments. At the 25,000-27,600PSI range (approximately 6,000 above PSI the SAMMI Proof Pressure of 19,500 PSI), the brass shell heads started to show signs of overstress: head flattening, extrusion into the extractor slot and cracking. The chambers and barrels showed no signs of expansion or of over-pressure at these pressures. The left barrels’ chamber opened up at 29,400 PSI and the right barrels chamber opened at 31,620 PSI. There were no signs of flaws in the newly exposed Damascus edges such as rust in the welds or inclusions even though the barrels were pitted. The failures started at the breech between the barrels, where the walls were thinned before assembly to narrow the breech width, and in which a horizontal hole is bored for the extractor guide pin, making this area considerably weaker than other areas of the breech.

Note: Handloading manuals often suggest that you start with a low initial powder loading and workup to the max recommended loading while looking for signs of overpressure such as damaged brass. The pressures in Toms' test were in the 25,000-27,600 range when brass damage became apparent. Sure doesn't seem to be a reliable method of avoiding an overpressure to me.

See: Vol. 16, Issue 2, Summer 2005, Part IX, below, for a comparison to Vulcan Steel (‘Fluid Steel’) destruction testing.

A Metallurgist tested these two barrels after failure; see “Rare As Hens Teeth”, above.

All Destructive Tests and Proof Tests were conducted remotely behind a shed wall, with the guns well tied down, using strings tied to the triggers.

He tested more low-pressure Smokeless loads, e.g., based on a Hodgdon Manual load: Federal Gold Metal plastic hulls, Federal 209A primer, Federal 12SO wad, 7/8 Oz shot with 17 Grains of Clays powder yielded 5600 PSI and 1200 FPS.

He tested Blackpowder loads, e.g., 3 Drams GOEX FFFg Blackpowder, Federal Paper hulls, 1 1/8 Oz Shot, Winchester 209 Primers, .135 nitro card, two ¼” Alcan felt filler wads yielded PSI 6,600 and 1167 FPS.

Note that the low-pressure Smokeless loads were close to, or below, the Blackpowder loads Peak Pressure with similar Velocity and Shot charges.

Vol. 11, Issue 3, Autumn 2000, ‘Forgotten 10s’ Part III

Tested many loads for the 10 Ga 2 7/8” Shell for both BP and Nitro.

For example:
116 Grains of GOEX FFFG Blackpowder 1 1/4 Oz of shot yielded 1,289 Ft/Sec and 5,900 PSI.
Using 32 Grains of RS 7625 with 1 ¼ Oz of shot yielded 1,170 Ft/Sec and 5,750 PSI.

Equivalent Smokeless loads, pressure and velocity, were developed.

Vol. 12, Issue 1, Spring 2001, “Finding Out For Myself” Part IV

Developed Smokeless loads for 2 7/8” 10 Ga shells. Pressures were typically in the 7,000-PSI range with shot loads of 1-¼ to 1-5/8 Oz and velocities in the mid 1,100 Ft/Sec range. Pressures and velocities were similar to that of BP.

Vol. 12, Issue 4, Winter 2001, ‘Finding Out for Myself’ Part V

Sherman measured the Pressure increases when shooting long shells in shorter chambers. He used differing 2 ¾” shells and shot loadings. He fired the 12 Ga 2 ¾” shells: in 2 ½” chambers, 2 ½” chambers with lengthened forcing cones and in the standard 2 ¾” chambers.

Pressure increases were generally in the 500-1,000 PSI range for the shorter chambers; not enough of a pressure increase to damage a shotgun assuming the starting load was reasonable. In the past, thick walled paper shells were thought to produce higher pressure increases in short chambers than and thin plastic shells; there was no consistent difference between them in the tests.

Previous tests of components changes, such as Primers, Shells and Wadding, often showed increases in pressure in the same range as short chambers.

Vol. 13, Issue 2, Summer 2002, ‘Finding Out for Myself’ Part VI

One Half the self-proclaimed ‘experts’ who rail against shooting Damascus guns with modern powders will argue that Smokeless/Nitro powders are faster burning than BP and they will produce excessively high pressures in the breech area. The other half will argue just the opposite; that BP is an ‘explosive’ that produces its’ highest pressure at the breech while modern powders will produce higher pressures down the bore and blowout the barrels where they are thinning. The common factor between both half’s: neither offers any proof, no peak pressure data, no pressure curves, no wall thickness measurements, no strength tests, no blown barrels, just a lot of faith in their own conclusions.

Another half will swear that it is the high pressure rise rate of modern powders that will damage the barrels. The last half just states that modern powders are stronger than BP; apparently they haven’t even looked at loading Manuals that contain many low-pressure loads or haven’t realized that using less powder yields lower pressures. (Yes, I know, too many half’s. That’s because the many ‘experts’ will just switch to another reason to not shoot Damascus when their first one or two reasons fall flat on their face.)

Sherman decided to test the high/low and fast/slow pressure arguments. He mounted strain gauges at 1”, 3”, 6”, 9” and 12” on a test mule (a inexpensive12 Ga single barrel; you don’t want Epoxy on your Best Gun and the concentric shape of a single barrel yields accurate pressure results). Various BP loads of GOEX FFFG were compared to modern powders.

He believes in using lower pressures in his collectable guns so he mainly used lower pressure BP loads (3 ¾ Drams BP and 1 ¼ Oz shot was the maximum), which gave pressures below 7,000 PSI, some less than 5,000 PSI, then loaded Nitros to match those pressure/velocities.

His conclusions:

* The modern powders tested produced similar pressures in the same areas of the barrel as BP, when loaded properly with similar shot loads and velocities.
* SR 7625 is a virtual clone to BP.
* Universal-Clays produced higher peak pressure but could be loaded to lower pressure if slightly lower velocities were acceptable.
* Blue Dot produced pressures similar to BP (one loadings pressure curve is shown in the ‘Some Curves Newer Than 1897’ post above).
* Quicker burning Clays powder gives lower down bore pressures than BP where your hand is, IF loaded to the same peak pressure.

Bottom line: modern powders can be used as a substitute for BP, with the always-present caveat that it must be done properly. Loading manuals should provide sufficient information for handloaders if you don’t deviate from their recipe. If you want to use the loads Sherman tested, I believe you can get new prints, in either hardcopy or electronic copies, from the Double Gun Journal.

(I’m not sure why he used six different strain cell locations; his Oehler 43 gives pressure/time curves which should be equivalent to pressure/distance curves when the shot loadings are the same. Pressure measurements units are available that give the calculated pressure/distance curves; a good investment if you are a serious handloader who wants to deviate from the Loading Manuals or test BP vs. Nitro.)

Vol. 15, Issue 1, Spring 2004, “Finding Out For Myself”, Part VII

Tested various Blackpowder, Smokeless and ‘Duplex’ loads (BP with a small charge of Smokeless in the cartridge base) for ‘Regulating’ (making both barrels hit the same aim point) a .450 3 ¼” BP Express rifle.

Vol. 15, Issue 4, Winter 2004, “Finding Out For Myself” Part VIII and Vol. 16, Issue 3, Autumn 2005, Part X

Tested various Blackpowder loads for the .450 3-¼” Express Rifle cartridge, originally a Blackpowder cartridge used in double barrel rifles. He developed several Smokeless loads with pressure curves and velocities similar to Blackpowder. For use in Damascus rifle barrels, of course.

Care had to be exercised with Hodgdons’ 777 BP substitute, on a volume/volume basis higher pressures could be generated. It also had problems with ignition reliability with no real advantages over BP.

One conclusion that is pertinent to shotshells: with the correct selection of Smokeless powders, equal peak pressures should be achievable with velocities equal or higher than BP.

For more information on the rifle loads in these two articles see:
http://www.levergunscommunity.com/viewt ... 93&start=0

Oddly, to me at least, were the linear pressures with no indication of an exponential curve that I would have expected for pressure sensitive powders. Out of curiosity I plotted data from a shotshell loading manual. It was also linear, at least over the short pressure range of the data, but it didn’t go through zero so it may a curve over a longer range. Are pressure sensitive Nitro powders another myth?

Vol. 16, Issue 2, Summer 2005, “Finding Out For Myself” Part IX

A ‘Vulcan Steel’ barreled Parker was tested to failure. The gun was similar to the Damascus barreled gun tested to failure in “Vol. 10, Issue 4, Winter, 1999, Part II”, above. Both were built on a No 2 frame so they likely had similar wall thicknesses (it wasn’t mentioned), they had close serial numbers and pitted barrels. (Both also had flaws that took them out of the collector category, so the loss of a irreplaceable gun would be lessened.)

Testing commenced with Proof pressures, which showed 1,485 Ft/Sec and 18,560 PSI in the test barrel. The pressures were raised in approximately 3,000 PSI increments. The first signs of stress occurred at 27,620 PSI and 1,734 Ft/Sec when the top rib extension raised up and the barrels started to come of the breech face. The next load, 29,620 PSI and 1,748 Ft/Sec, showed the first damage to the Barrels, stretching the chambers by .009” (that is it was enough pressure to exceed the elastic limit of the metal, repeated firing at this pressure would eventually lead to Fatigue Failure). This is the load that blew the left chamber of the Damascus barreled gun.

The next load at 31,620 PSI and 1,801 Ft/Sec blew both chambers of the Vulcan Steel barrels. It is the same load that blew the right chamber of the Damascus barrels.

Note that both the Damascus and Steel barrels failed at almost three times the SAAMI recommended maximum shell pressure of 11,500 PSI for the 12 Ga.

Sherman’s conclusions: there is no significant strength differences between the Damascus and Fluid Steel barrels tested, both barrels showed strengths well in excess for that needed for modern maximum loads. He still prefers using shells with moderate pressures in his guns (which for these barrels would be one-fourth to one-fifth of the failure pressure).

Vol. 17, Issue 3, Autumn 2006, “Finding Out For Myself” Part XI

Sherman reported on the testing of eight Damascus barreled SxS’s using Remington 12 Ga Proof Shells loaded to SAMMI specs that measured 18,200 PSI in a test barrel. They were all American made guns; Remingtons, Parkers and L. C. Smiths. None of the guns were in pristine condition; some were badly corroded or showed signs of over stress such as looseness between the Barrels/Receiver. One already had a slightly bulged chamber. (Belgium gun haters: all the guns tested in this series probably had Belgium made Barrels.)

The Barrels were carefully measured before and after the tests. None of the Damascus barrels showed any signs of overstressing such as bulging or splitting, that is, they passed a modern Proof Test. Some guns that were off-face before the testing began went further off-face, this is likely due to stretching of the receivers or the barrel lugs, not barrel failure. Some loose ribs loosened further.

The previously bulged chamber must have been exposed to pressures above that of the Proof Load in a past life; even it showed no further stressing.

Vol. 17, Issue 4, Winter 2006, “Finding Out For Myself” Part XII

Sherman tested seven more Damascus SxS Wallhangers with Remington Proof loads (1-1/2 Oz #9 Shot tested at 1,378 Ft/Sec and 18,280 PSI tested by Tom Armbrust). Included were two Remington 1894s, two L.C. Smiths and three Remington 1900s. All passed Proof pressure with no signs of bulging.

From the article:

“The fact discovered in these most recent tests is this: A total of 30 Damascus barreled guns were severely shocked with modern proof ammunition that develops 18,000+ PSI. Although the guns were in generally bad condition and some of them suffered further mechanical degradation from abusive testing, none of the barrels failed in any way that would have caused them to be rejected at nitro proof.”

Note that some of the guns were in such poor condition before being tested (severe pitting, loose cracked stocks, off-face with the breech) that they would likely have been rejected for testing at an English Proof House without quite a bit of ‘Smithing.

Many of the test guns had chambers shorter than the 2 ¾” Proof loads which may have raised the breech pressures even higher than the 18,200 PSI measured in the test barrel.

To test the claim that smokeless powders generated higher down bore pressures that could burst Damascus barrels, a ‘maximum’ loading of Blue Dot was tested (as much powder as would fit in the shells). Breech pressure increased from 6,000 PSI in an earlier test in which Blue Dot powder virtually duplicated the pressure curve of Blackpowder, to 10,000 PSI for the ‘maximum’ load. Down bore pressures of the ‘maximum’ load were virtually the same as both the lighter loading of Blue Dot and the Blackpowder load, making it unlikely that even a heavy load of smokeless powder could cause down bore failures. (See Unique, below for a test with a faster Nitro. It blew the chamber, not the down-bore section.)

Vol. 18, Issue 1, Spring 2007, “Finding Out For Myself” Part XIII

Sherman decided to find out how thin of a barrel wall was too thin. He had an L.C. Smith, which had passed earlier Proof pressures, bored out until the muzzle walls were only .020”, an often mentioned minimum thickness. The bores were now .783” and .782”; technically 10 Ga bores. Nine Oz’s for bore metal had been removed, over ½ Lb! He measured the ID and OD of the barrels and calculated the wall thickness at:

Distance:----6”---------9”-------12”--------15”--------18”-------21”-------24”-------26”
Right:------ .046------.026-----.021-------.018-------.017-----.019------.019------.020
Left:--------.047-------.027-----.024-------.021------.021------.021------.021-----.020

(Note, in my opinion, measuring ID and OD to calculate wall thicknesses is only accurate if the bores are concentric, since there was no indication that they were concentric, it is possible that the walls could have been even thinner in places than those calculated.)

Assuming the bores were originally the nominal .730” for a 12 Ga, the wall thickness at 9” was calculated to be ½ of the original thickness.

A single firing of the Proof shells (18,280 PSI) did not affect the barrels. A second firing, in which the barrels ‘doubled’ (both barrels firing together) bulged the left barrel at the 9” location by .007”. Makes sense since the barrel was only .027” (and possibly less if the bore wasn’t concentric) in an area where the pressure were still relatively high. The right barrel remained unfazed.

A third Proof round burst the left barrel where it had previously bulged.

The right barrel survived ten Proof rounds without any change and it was only .026”, at most, 9” from the breech! . This tends to disprove the belief that a Proof test will weaken a barrel so that it could burst with further normal pressure firings.

Sherman’s conclusion: Damascus is tough! Wall thickness should vary with the pressures at a particular barrel location.

A number of barrel obstruction tests were performed on another gun that had survived the Proof pressure tests. The shells used had 3 ¼ Drams of Blackpowder and 1 ¼ Oz of shot, a typical BP loading. The barrels burst or bulged when: a loaded 20 Ga shell was stuck in the barrel just past the chamber, a rag was wedged down the bore and a wad of sod was wedged in the muzzle. Lesser obstructions such a wadding in the bore were blown clear without damage.

To test his hypothesis that the cause of Damascus barrel failures around the 1900 period were due to the use of Blackpowder volumetric measures to measure modern Nitro/Smokeless powders, he used a volumetric 3 ¼ Dram measure to load a shell with Unique powder and 1 ¼ Oz of shot. According to Sherman, ‘Unique’ is a newer name for ‘Infallible’, a powder that is largely unchanged since the 1890’s. This powder charge, when weighed, was 56 grains or over two times a typical load of 25 grains of Unique.

The first round of this intentionally miss-loaded shell violently blew the chamber open, sending shrapnel in all directions.

This is a likely cause of Damascus failures since reloaders of the time were conditioned to using the volumetric measures for BP, and also for the earlier semi-smokeless powders which gave pressures similar to BP when used in equal volumes. The more powerful modern smokeless powders (higher pressure for the same weight or volume) that were introduced after 1888 were sold with little warning of the consequence of overloading, particularly with volumetric measures.

(Note, the manufacturer recommends Unique for use in both handguns and shotguns. This always seemed questionable to me: handguns need a fast powder that will produce their pressure in short barrels but long guns can use slower powders to produce a gentler lower pressure curve. Using fast powders in long barrels can be more efficient (less powder is required to produce high pressure in the low volume near the breech than is required to produce the same pressure in the larger down bore volume) but both the likelihood and consequences of a double charge of the lower required volume of faster powders is considerably increased. The double load of Unique blew the chamber but a double charge of slower Blue Dot produced less than a doubled pressure. See above.)

Sherman’s conclusions: Overloaded shells cause burst or bulged chambers. Bursts or bulges down bore are caused by obstructions. Damascus wrongly earned its’ reputation for weakness from a combination of miss-loading modern Nitro powders and barrel obstructions.

I can’t find fault with any of these conclusions.

Vol. 19, Issue 2, Summer 2008, “Finding Out For Myself” Part XIV

Sherman tested seven more American Damascus SxS’s to SAMMI Proof pressures. Some of these guns were severely rusted; all were considered ‘Wall-Hangers’.

‘Laminate’ Barrels (at times referred to as ‘Twist’ barrels, the terms used varied with time and user) are often claimed to be weaker than ‘Damascus’ Barrels (laminated steel twisted into a curly pattern). Six of the guns had plain Twist Barrels.

The Laminate/Twist barrels stood the proof loading as well as the Damascus barrels. One of the Twist barrels had previously been bored from the nominal .730” of a 12 Ga to .760” right and .764” left, leaving the barrels thinner than original and it still passed Proof pressures.

Two of the Parkers were 10 Ga with 2 5/8” and 2 7/8” Chambers. They were tested with 10 Ga 3 ½” Proof loads measured at 19,840 PSI in the test barrel. Neither of guns Barrels showed any signs of over stress even with the long shell/short chambers likely raised the pressure above that in the test barrel. One gun, which was loose at the face, did loosen more.

A total of Twenty-Two Damascus Barreled Guns (including ‘Damascus’ and ‘Twist’ or ‘Laminate’) had been tested at SAAMI Proof pressure. None showed any change in the Barrels or their Chambers. Some that were ‘off-face’ showed an increased distance between the Breech end of the Barrels and the Receivers face.

Conclusion: ‘Twist’ and Laminate’ barrels passed Proof pressures equally as well as Damascus and Steel barrels. All the barrels had passed Proof pressures.

(The articles in the DGJ were published out of order, thus the earlier reference to 30 guns and the later reference to 22 guns.)

Vol. 19, Issue 3, Autumn 2008, “Finding Out For Myself” Part XV

Sherman tested Trail Boss, a low density Nitro powder, as a replacement for Blackpowder in a .450-3 ½” Express Rifle cartridge. With a case-full loading of 36 Grains of Trail Boss, the velocity of 1,799 Ft/Sec was close to that obtained with Blackpowder, but the pressure of 33,000 PSI was about 50% above that of BP.

In modern high pressure necked rifle cartridges a full case of Trail Boss may provide lowered pressures and velocities if that is what you want. But compared to BP at the same velocities it can produce higher pressures; it doesn’t appear to me to be a good substitute in shotguns. (Curves for Trail Boss in a rifle cartridge are shown in “Some Pressure Curves Newer Than 1897”, above. It is a relatively fast powder in rifles.)

Surprisingly, compressing more Trail Boss into the case actually decreased both pressure and velocity. My only explanation is that the flame front could not propagate through the soft easily compressed powder; it probably had less open space between the grains for the flames to travel. Lower flame front speed would lead to a lower ignition rates and therefore lower pressure rise and lower peak pressure."

[Kittu]

thanks sir
for great information on loads about damascuss barrels.there are thousands of damascuss barells shotguns in india still in use and owner fires all sorts of ammo trough them i havent heared of any incident that damacuss barrel was exploded.americans were first who feard most of damascuss barrels.it was a myth that damascuss barrels were inferior to fluid steel barrels.it was it a pripogenda from fluidsteel barrel manufatureres by blowowin up some damascuss barrels to promote less labourel fluid steel?