John Brindle, author of Shotgun Shooting: Techniques & Technology published a 5 article series in The Double Gun Journal, “Black Powder & Smokeless, Damascus & Steel”. Through the wonders of Google's digitized library, we have more research material available than did Brindle when writing c. 1992-1993, but his series remains an important resource.

My local library was able to obtain PDF copies of each article from:
Pritzker Military Library
104 S. Michigan Ave, Suite 400
Chicago, IL 60603
Copyright is still in effect so I can't share the PDFs

DGJ lists the complete issues as available for $30 (blemished $25)

Volume 4, Issue 2, 1993 “Some Modern Fallacies Part 1”, p. 128
Barrel methodology, black and early smokeless powders.
In discussing 1800s pattern welded barrels “The ‘iron’ used in these barrels was really various kinds of soft steel with a low percentage of carbon...”

Volume 4, Issue 3, 1993 “Some Modern Fallacies Part 2”, p. 49
Comparison of black and smokeless powders & pressures

Volume 5, Issue 1, 1994 “Some Modern Fallacies Part 3”, p. 9
Review of the Birmingham Proof House Trial with thoughts on the conversion to steel shotgun barrels.
“Thus steel had proved stronger than Damascus in this test, but the strength of both was such that this did not matter one bit, such was the margin of safety in a barrel of either material of suitable dimensions and without flaws.”

Volume 5, Issue 2, 1994 “Some Modern Fallacies Part 4”, p. 9
In depth discussion of Proof and Service pressures

Volume 5, Issue 3, 1994 “Some Modern Fallacies Part 5”, p. 11
Continued discussion of Proof and Service pressures, and summary of the article series.

An important point made by Brindle based on this study. Note the pressures with both Schultze and "E.C." are lower than with Curtis & Harvey black powder

…….....…………..12……….16……….20
C.&H. No. 4…6,373…..7,078…..6,944
C.&H. No. 2…7,459…..8,310..…8,288
Bulk
Schultze……..4,424…..6,272…..7,246
“E.C.”…..…..3,685…..6,171…..8,322
Dense
Walsrode….….9,363………..…….10,741
S.S…….…..…..9,800………..…….10,539
S.S. ("Smokeless Shot-gun" was abandoned because of the higher pressures)

Curtis & Harvey was "T.S." (treble strength) and NOT equivalent but No. 6 similar to Fg, No. 4 FFg, and No. 2 FFFg

A second study using “Eley’s Ordinary Case” showed slightly different, but similar pressures.

"The pressures produced in the breechloader by black powder, as black powder was actually loaded at the end of the 19th century, were not significantly lower than those given by smokeless (then often termed “semi-smokeless”) powders developed as a substitute for, and an improvement on, black powder."

Drew, are the above pressures shown for equal shot weight and velocity ?

Thanks Daryl, I should have included that

LOADS…...................………..…..….….……1 1/8oz…1oz..7/8oz.
………………………….....................…...…...…12g…..16g…..20g
Curtis & Harvey No. 4 T.S. Black Powder…...82……74….…66 grains
Schultze and “E.C.” Bulk Smokeless.…..….….42……37….…33
Walsrode Dense Smokeless...…......…….……..28……24….…22
Cases were “Eley Best Quality Green Case”

82 gr. C&H No. 4 Black, 42 gr. Schultze and "E.C. No. 1" Bulk, and 28 gr Walsrode Dense are 3 Dr. Eq.

Black and Nitro powder Service and Proof Charge Pressures
https://books.google.com/books?id=inQCAAAAYAAJ&pg=PA296&dq
Experiments to ascertain the pressures given by service charge and proof charges used in England have been carried out by The Field. Under the existing Regulations of Proof in England, a “service charge” is specified for every bore, and the compulsory definitive proof is made with double the service charge of proof-house powder and 1 1/3 (times) the service charge of No. 6 shot. Besides the compulsory proof, a supplementary proof with other kinds of powder is permitted, if applied for. Many other charges, both larger and smaller than the officially stated “service charge”, are in constant use.



Curtis & Harvey T.S. (Treble Strength) No. 6 was coarse Black Powder somewhat similar (but not equivalent) to Fg; No. 4 medium, FFg; No. 2 fine, FFFg.
https://books.google.com/books?id=mFcCAAAAYAAJ&pg=PA271&lpg
“S.S.” (Smokeless Shot-gun) was a Bulk Smokeless powder made by Smokeless Powder Co. It was discarded as loading with higher charges of powder produced significantly greater pressures than “E.C.” or “Schultze”.

Pressures were measured using crushers (LUP) reported in pounds/ sq. inch and modern piezoelectric transducer pressures would be 10 - 14% higher.

12 bore
Nitro 1 1/8 oz. with 42 grain Bulk Smokeless = 3 Dr. Eq. (1200 fps): 5330 - 6110 psi
Nitro 1 1/4 oz. with 45 grain = 3 1/4 Dr. Eq. (1220 fps): 6360 - 8620 psi

16 bore
Service charge 1 oz. 2 3/4 Dram Eq. = 38 gr. Bulk Nitro powder.
C&H No. 4 - 7,480; “Schultze” - 8,250 psi; “E.C.” - 8,960 psi

20 bore
Service charge 7/8 oz. 2 1/2 Dr. EQ. = 34 gr. Bulk Nitro powder
C&H No. 4 - 8,240; “Schultze” - 8,220 psi; “E.C.” - 9,100 psi

This should 'splain why c. 1900 pattern welded and decarbonized steel barrels were "Bored For Nitro Powder"

As said, we have much more information today regarding turn-of-the-century and pre-WWI powders. Brindle did make some mistakes regarding powder Dram Equivalency, and it should be clear why the inattentive or casual shell loader could blow up his shotgun

42 grain = 3 Dram Equivalent Bulk Powders
“E.C.” No. 1
“Schultze”
Curtis & Harvey “Amberite” (40 grains)
Sporting Smokeless Powder Syn., Ltd “Cannonite Shot-gun”
Smokeless Powder Co. “S.S.” (Smokeless Shot-gun) (43 grains)
Cooppal & Co. “Cooppal’s No. 1”
United States Smokeless Powder Co. “Gold Dust”
Dynamit Nobel’s Troisdorf Powder Co. “Troisdorf” (41.5 grains)
American Wood Powder
“J.B.” Powder

36 Grain = 3 Dram Equivalent Bulk Powders
DuPont Bulk (36.5 grains)
Hazard Powder Co. “Blue Ribbon” (37 grains)
“E.C.” No. 2 (Improved)
“New Schultze”

33 Grain = 3 Dram Equivalent Bulk Powders
“New E.C. (Improved) No. 3” (Introduced in U.S. in 1904)
Curtis & Harvey “Smokeless Diamond” (1903)
Walsrode Smokeless & Waterproof Gun Powder Co. “Walsrode Gray”
Louis Muller & Cie S.A. “Mullerite No. 2”
Nobel’s Explosive Co. “Empire”
“Cooppal’s No. 2” (30 grains = 3 Dr. Eq.)


………………..BULK…………….-----------------------.........……………….DENSE…………..
.......E.C.No.1.....DuPont……Schultze-----Walsrode Green....Ballistite…..Infallible

3 Dram....42...........36.5........42................30………..…...24..............21 grains
3 1/4…...45.5..........41..........45................32……..….…..26..............23 grains
3 1/2…...49............43..........48................34………..…...28..............25 grains

The original “Schultze” & “E.C.” No. 1 Bulk Smokeless were 14 grains/drachm.
“New Schultze” & New “E.C.(Improved) No. 2” Bulk Smokeless were 12 grains/drachm.
“E.C. No. 3” was 11 grains/drachm or 33 grains = 3 Dr. Eq.

BTW: Mullerite was marketed by Louis Muller & Cie S.A. des Explosifs de Clermont, Liege in 1899. No. 1 was a Bulk Smokeless; No. 2 a faster burning “33 grain” Bulk powder. Poudreries Réunies de Belgique acquired Muller & Cie in 1919.
http://books.google.com/books?id=inQCAAAAYAAJ&pg=PA343&lpg

1908 Rod & Gun Canada



Mullerite Bulk smokeless was still offered in the 1915 New York Sporting Goods Co. catalog.

Ol' Louis borrowed the Parker 1893 Columbian Exposition Trade Card for his cans
http://books.google.com/books?id=rblIAAAAMAAJ&pg=PA1114&lpg








Wolffe & Co. in Walsrode, Prussia had a London agent, George Beutner, in 1892 then established The Walsrode Smokeless & Waterproof Gun Powder Co. in 1894. Walsrode Gray 33 grain = 3 Dram; Green 30 gr. = 3 Dram.
In 1895, agents included Von Lengerke & Detmold, N.Y., Von Lengerke & Antoine, Chicago, M.F. Kennedy & Bros., St. Paul, and Clabrough, Golcher & Co.
In 1895, President Grover Cleveland order 1,800 ‘ducking’ shotshells from William Wagner, Washington D.C. and specified they be loaded with Walsrode
http://library.la84.org/SportsLibrary/SportingLife/1895/VOL_25_NO_01/SL2501014.pdf
In 1903, Schoverling, Daly & Gales advertised as the “Sole U.S. Agents” and listed Walsrode as “The Original Dense Smokeless”

Walsrode borrowed "Monarch of the Glen" by Sir Edwin Henry Landseer

1915 Forest & Stream

Drew: thanks again for your scholarship. I always look forward to your posts.

Drew;
A couple of comments.
I believe that at least some companies when they said "Bored For Nitro powder" were speaking of the bore diameter. It appears many guns in the Black Powder era were made for use with brass shells & had oversize bores for the larger wads. Smokeless loads were put up in paper shells thus the Bored for nitro, meant the bores were more standard for the nominal gauge to fit the smaller wads in paper shells. The fact they were boring Twist & Damascus "For Nitro Powder" dos show they were condoning it's use.
The 2nd comment is that in relation to bore size the 2 3/4-1 in 16ga & 2½-7/8 in 20ga are both heavier loads than the
3-1 1/8 12ga load. This would account at least in part for the higher pressures recorded in these two gauges.

I would not dare read the minds turn-of-the-century ad men but Miller's point re: "Bored For Nitro Powder" is well taken. Parker Lifters, 12g and esp. 10g are frequently "over-bored" by the 1890s .729" standard.

Remington's ad verbiage was more precise; this from 1895. "Guaranteed..."



H&A in 1903 "Guaranteed..."



Folson still had the "Bored for Smokeless or Black Powder" in the c. 1915 & 1916 catalogs

Drew;
My post on the bored for nitro is primarily based on Lefever catalogs. In their catalog circa 1892 they state under "For Trap or Duck Shooting" for brass shells to use two felt wads over powder two sizes larger than bore of gun, for paper shell same except one size larger than bore.
under "For field Shooting" they state for our new gun built for the use of Nitro Powders use one paste-board wad & three felt wads same size as bore.
in another section of the same catalog they state that their guns made especially for Nitro Powders; "These guns we are boring smaller for the use of wads same size as bore. We find by testing these powders better results are obtained with a slightly smaller bore in order to prevent the escape of gas.
In this catalog the only grade offered with steel barrels was the Optimus with Whitworth Fluid Steel @ a list price of $400.00. Whitworth was also an option listed for the Optimus grade in an 1889 price list, I do not know how much earlier it was available.
Essentially it appears to me the "Bored for Nitro" has nothing to do with the actual metal the barrel was made from, but rather the size of it's bore.

Interesting evolution by Hunter Arms. The Syracuse guns were offered in 3 frame sizes, and possibly JDW would know if the bore varied with the frame size

1886



1902 Sears, Roebuck & Co. Catalogue No. 111 "Bored For Nitro Powder"



1907 Sears, Roebuck & Co. Catalogue No. 116 "All our guns are tested with heavy loads"..."Choke bored for black or smokeless powder". Courtesy of Gary Rennles



1905 "For Nitro Powder"



1918 E.C. Simmons, St. Louis "Bored For Nitro Powder" again

Some other variants

1902 J. Stevens Arms & Tool Co. "Choke Bored For Nitro Powder"



1917 Stevens Riverside No. 225 hammergun with "Nitro Steel" and No. 215 hammerless with "Rolled Steel" barrels "tested with nitro-powder before they leave the factory..." "Bored for both Black and Smokeless Powder."



1918 Field Grade Ithaca "Smokeless Powder Steel Especially Adapted for Nitro Powder"

the wealth of knowledge that can be found on this forum is remarkable...thanks to all who contribute.

Drew, thanks for the reference to Brindle's fine series of articles. I've had them in my files for years. Some corrections made since, but mainly I think because the Internet back then was not what it is today.

I always found Brindle's articles to be interesting and a valuable contribution to what was then the collective wisdom on shotguns.

Would have been helpful if the U.S. ad men had just come out and said what they meant to say like W.W. Greener

Keeping with the over-the-top ad verbiage theme Lefever AA "Finest A-1 Quality Silver Steel Damascus Highest Proof" courtesy of Richard Brewster

This is pretty clear.

Colton Manufacturing Co. in the Sears 1900 Catalog No. 110 "Shoots Any Powder...made so strong at every point that it is adapted to the use of any grade of white, black or smokeless powder."



Andrew Fyrberg "Chicago Long Range Wonder" in the 1902 Sears, Roebuck & Co. Catalogue No. 111. "Our barrels are made for the highest explosive gun powders used, such as white or nitro powder...and could be used as safely as the regular black powder."

Drew, thank you for all the hard work and dedication you put into this research!! Many, many times I turn to your articles for answers to many questions I, and others have regarding barrel steel. THANK YOU THANK YOU THANK YOU!!!

At the risk of repeating myself...I will because this is probably the most important summary to answer the question "What load should I use for my vintage gun (which has been evaluated by a double gun specialist smith and found to have adequate wall thickness and mechanical & stock integrity)?"

c. 1900: The “standard” U.S. 12 gauge field and inanimate target load was 1 1/4 oz. shot with 3 1/4 Dram Equivalent (1220 fps) of Bulk Smokeless with a modern transducer pressure of 8000 - 9500 psi.
Just before WWI: The “standard” U.S. 12g field and inanimate target load was 1 1/8 oz. shot with 3 Dr. Eq. (1200 fps) Dense Smokeless with a transducer pressure of 8,500 - 10,000 psi.

12g pressures
1 1/8 oz. 3 Drams (82 gr) Curtis & Harvey’s No. 4, T.S. Black Powder (somewhat similar to medium grain FFg) was about 6500 psi.
For comparison, 1 1/8 oz. 3 Drams (1200 fps) of DuPont FFFg Black Powder (82 grains) is about 5000 psi.

1 1/8 oz. 3 Dram Equivalent of BULK Smokeless was 6500 - 7500 psi.
1 1/8 oz. 3 Dr. Eq. of DENSE Smokeless was 8,500 - 10,000 psi.
1 1/8 oz. 3 1/4 Dr. Eq. BULK Smokeless was about 8500 psi.
1 1/8 oz. 3 1/4 Dr. Eq. DENSE Smokeless was 9500 - 10,500 psi.

1 1/4 oz. 3 1/2 Dr. Eq. BULK Smokeless was about 11,750 psi
1 1/4 oz. 3 1/2 Dr. Eq. DENSE Smokeless was 12,600 psi
Pressure is beyond the modern SAAMI recommendation of 11,500 psi

16g - 1 oz. 2 3/4 Dr. Eq. BULK Smokeless was about 7000 psi.

20g
7/8 oz. 2 1/2 Dr. Eq. BULK Smokeless was 8000-9000 psi.
7/8 oz. 2 1/2 Dr. Eq. DENSE Smokeless was about 11,000 psi.
Up until about WWI the standard 20g load in the U.S. was 7/8 oz. with 2 1/4 Dr. Eq. Bulk or Dense Smokeless powder.
7/8 oz. with 2 1/2 Dr. Eq. had been the standard British 20g load even before the 20g was offered by U.S. makers.

Thanks, Drew. Did you convert those old LUP readings to approximate psi as measured by modern transducers? If not, that would put those 1 1/4 oz loads well beyond the current SAAMI standard.

The reported pressures are converted to modern piezo transducer numbers using Burrard’s formula if originally expressed as Tons/sq. inch by LUP (Lead [Crusher] Units Pressure), or by adding 10-14% if expressed as PSI by LUP

Reported pressures varied significantly depending on pre-WWI British, between the wars U.S. (mostly Coxe's data), and post-WWII

Thanks. It gets very confusing when you read older stuff on pressure, even without the extra confusion the Brits caused when they started using the "tons" figures.

Indeed Larry. Even Wallace H. Coxe joined the "Tons" parade

"Smokeless Shotgun Powders: Their Development, Composition and Ballistic Characteristics", 1931

Western Cartridge Company’s 12g ‘Super-X Field’ 2 3/4” 1 1/4 oz. 3 3/4 Dram Equiv. shell with DuPont Oval was introduced in 1922. Dram Eq. is listed as 3 but is much more likely 3 3/4.
Charge was 1 1/4 oz.

Using the estimated Tons Lead Crusher Pressure (Cp) conversion to PSI (pound force per square inch) (Cp x 1.5) - .5 = TSI, TSI X 2240 = PSI.

Ballistite maximum pressure at 1” was 4.9 Long Tons = 15,344 psi
Schultze at 1 3/4” was 4.5 Long Tons = 14,000 psi
DuPont Bulk at 1 2/3” was 4.1 Long Tons = 12,656 psi
FFFg at 1 1/2” was 3.8 Long Tons = 11,648 psi
Oval at 2” was 3.5 Long Tons = 10,640 psi
All the curves essentially meet at about 3 1/2”.



Those are serious beyond SAAMI max. pressures in loads which the turn-of-the-century Live Pigeon shooters were using routinely, with those "time bomb" Damascus barrels