Is my gun safe? What load was my gun designed to shoot?
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Author:  Drew Hause [ Sun Mar 27, 2016 5:27 pm ]
Post subject:  Re: Is my gun safe? What load was my gun designed to shoot?

Prior to 1924, the Belgian and British Service (using) load for 12g 2 3/4” shells was 1 1/4 oz. / 3 1/4 Dram Eq. (1220 fps). The pressure of that load would have been about 8500 psi with BULK smokeless powder; with DENSE smokeless 9,500 - 10,500 psi.
2 1/2” shells were usually loaded with 1 1/8 oz. shot and 3 Dr. Eq. of BULK Smokeless with a pressure of 6500 - 7500 psi; DENSE Smokeless was 9000 - 10,000 psi.

During WWI the standard English 12g load was dropped by law (to conserve the supplies of lead and powder) to 1 oz. and 3 Dr. Eq. Bulk smokeless. After the War, 2 1/2” shells were generally loaded with 1 1/16 oz. shot and 3 Dr. Eq. Bulk or Dense smokeless powder.

In the 1925 British Proof House revisions, the 2 1/2” & 2 5/8” 12g service load was reduced to 3 Drams with 1 1/8 oz. shot with a mean max. service pressure of 3 1/4 tons = (converted using Burrard's forumula) 9,682 psi.

After the 1924 Belgian Proof House revisions, the 12g max. service load was 600 kg/cm2 = 8534 psi + 10 - 14% by piezoelectric transducer measurement or about 9,600 psi.

Independent testing showed the 3 Dr. Eq. 1 1/8 oz. Old Style CF AA Winchester Trap Load to be 9,600 psi; AA Xtra-Lite 1 oz. WAAL12 8000 psi.

More information ... FU/preview

Author:  67galaxie [ Fri Apr 01, 2016 10:58 pm ]
Post subject:  Re: Is my gun safe? What load was my gun designed to shoot?

Bernardelli umberto #1 full and mod. Can I shoot 3" mags?

Author:  Drew Hause [ Mon Apr 04, 2016 12:12 pm ]
Post subject:  Re: Is my gun safe? What load was my gun designed to shoot?

No one on the internet can tell you if YOUR gun is safe, with any load.
It should be marked 76mm/3" and carry 'TWO stars over PSF' marks for "Superior Proof"
More, but somewhat contradictory, information here ... 93b5d7fcf4
If you are inquiring regarding steel shot, that is a much more complex issue and you might post images of your gun's marks on the General Discussion Forum

Author:  Drew Hause [ Mon Apr 04, 2016 12:37 pm ]
Post subject:  Re: Is my gun safe? What load was my gun designed to shoot?

Post-Western Super-X (1922) load pressures

Progressive Burning DuPont Improved Military Rifle (I.M.R.) Powders were introduced in 1914. DuPont Oval was developed for the 1922 introduction of Western Cartridge Company’s 12g ‘Super-X Field’ 2 3/4” 1 1/4 oz. 3 3/4 Dram Equiv. shell. The Peters Cartridge Co. ‘High Velocity’, United States Cartridge Co. ‘Ajax Heavies Long-Range’, Remington Kleanbore ‘Nitro Express Extra Long Range’ (the boxes were marked “3 3/4 Drs. Equiv.”), and Winchester Super Speed (also marked 3 3/4 Dr. Eq.) loads soon followed.
Western’s 3 inch ‘Record’ with 1 3/8 oz. of shot was released in 1923.

Western Cartridge Co. never marked the Super-X ‘Field’ or ‘Record’ boxes with “Dr. Eq.” stating only “Maximum Load”. It is presumed that 12g ‘Super-X Field’ 2 3/4” 1 1/4 oz. was 3 3/4 Drams Equiv. or 1330 fps, and the 3” 1 3/8 oz. ‘Record’ was 1275 - 1295 fps (the speed of 1 1/4 oz. 3 1/2 Dr. Eq. loads). Other sources reported 1315 fps, presumably at 3 feet from the muzzle.

In c.1927-1935 Western Cartridge Co. pamphlets “Super-X The Long Range Load” by Capt. Chas. Askins the 12g “Duck Load” (not specified but presumed to be 1 1/4 oz. Super-X “Field”) is described as 3 1/2 dram (38.5 gr. Powder; also not specified but no doubt DuPont Oval at 11 gr./Dram) at 1400 fps (at the muzzle rather than 3 feet) and 1000 fps at 40 yards, with a breech pressure of 3 3/4 tons or about 11,480 psi by Burrard’s conversion.
3” Super-X Record with 1 3/8 oz. at MV 1400 fps with 4.25 Tons psi = 13,160 psi

From the 1928 edition of “Smokeless Shotgun Powders” by Wallace Coxe, ballistic engineer of the Burnside Laboratory of the E.I. du Pont de Nemours & Co. “DuPont Oval can be loaded with 1 3/8 ounces of shot in a 12-gauge shotgun to develop the same velocity and pressure as obtained with a load of 3 1/2 drams of DuPont Bulk Smokeless Powder or 28 grains of Ballistite and 1 1/4 ounces of shot. The relation naturally holds with other charges, but as DuPont Oval is used principally for maximum loads the comparison is more striking as it shows the possibility of using a heavy load with DuPont Oval that would be an abnormal load were it used with DuPont Bulk Smokeless, Ballistite, or other existing old-style types of shotgun powders.”
Coxe reported 3 1/2 Dram Eq. 1 1/4 oz. loads (1275 fps) and 40 yard average fps:
NOTE: pressures were measured by crushers (LUP) and modern transducer measurement pressures would be 10 – 14% higher
DuPont Bulk smokeless powder - 11,700 psi, 943 fps
Schultze Bulk smokeless powder - 11,800 psi, 941 fps
28 grains of Ballistite Dense smokeless powder - 12,600 psi, 966 fps
Note all 3 are greater than the SAAMI 12g 2 3/4” recommended maximum
pressure of 11,500 psi.
40 grains of DuPont Oval Progressive Burning powder - 9,400 psi, 981 fps

From “Smokeless Shotgun Powders: Their Development, Composition and Ballistic Characteristics”, 1933. The pressures (PSI by LUP) are for a 3 Dr. Eq. 1 1/4 oz. load + 10-14%
DuPont MX = 9,800 psi
DuPont MX Smokeless was a Dense Multi Base Powder introduced about 1930. 25.5 grains was a 3 Dr. Eq. and it was promoted as a 1 1/4 oz. Trap load. It was replaced in 1954 with IMR PB.
DuPont Bulk = 9,600 psi
FFFg = 9,000 psi
DuPont Oval = 8,700 psi

Author:  Drew Hause [ Sat Oct 22, 2016 10:13 am ]
Post subject:  Re: Is my gun safe? What load was my gun designed to shoot?

I've added a number of modern load pressures, as reported by the manufacturer or by independent testing, at the bottom here ... FU/preview

Author:  stepmac [ Sun Nov 27, 2016 6:16 pm ]
Post subject:  Re: Is my gun safe? What load was my gun designed to shoot?

I've enjoyed reading the posts re this topic. I own dozens of old guns of all kinds. I have shot all but a few. I have a Hall rifle, Smith and Burnside carbines, Springfield muskets, both flint and percussion and an 1861 Springfield. I've got Lefever, L.C. Smith, Parker and Crescent shotguns. I've got some very old guns, Hardy shotguns c.a. 1845, frontier muzzleloading rifles c.a. 1840 and Colt pistols. I shoot them all. Some like the Parker GH and Ross MkII straight pull I first tied to a tire and touched them off with a long string. Some, the Hardy Bros muzzle loading shotgun and Pioneer rifle I shot when I was a kid and knew nothing about the dangers of shooting old guns. I just poured in BP from a powder horn until I decided to stop. Some I overloaded just for the heck of it. Some I had no idea how to load and just loaded them until the chambers were full....Colt percussion pistols and a Starr DA for example. I shot original duelers and screw barrel derringers. I have shot several original Sharps rifles a lot, some percussion and some cartridge, some shot extremely well and some shoot around corners. I shoot the old BP Mausers and a Danish Rolling Block. I own an old British fowler flintlock that I cannot bring myself to shoot. Had a gunsmith measure wall thickness of the barrel. I asked him if it'd be safe to shoot. He said, "Well, I don't know, but there's a lot of steel in that barrel."

I don't hesitate to shoot an old gun if it looks sound to me. Most of the shotguns people are concerned about in this thread are safe to shoot....unless you get a bad one.

Author:  Drew Hause [ Wed Apr 05, 2017 2:37 pm ]
Post subject:  Re: Is my gun safe? What load was my gun designed to shoot?

Plain or Common Twist barrels on a c. 1890s J. Manton, Birmingham


Which survived 1200 BAR re-proof in 1992

12g CIP “High performance/Superior Proof”
Service 1050 BAR = 15,229 psi
Maximum statistical individual pressure 1200 BAR = 17,405 psi
Magnum proof 1320 BAR = 19,145 psi


Author:  Drew Hause [ Sat Oct 06, 2018 5:31 pm ]
Post subject:  Re: Is my gun safe? What load was my gun designed to shoot?

Recreation, September, 1898 ... -PA216&lpg
A writer in RECREATION claimed that blued barrels, such as used on some of the cheaper American guns, are as strong as the imported twist barrels. My observations teach me this is a mistake. Anyone who is familiar with gun making knows the cheap blue barrels are all made from a good grade of rolled iron, which is bored at the factories where used. The grain of the metal must necessarily run lengthwise, and consequently will not stand the bursting strain which the same metal would stand if the grain ran in a spiral course. Besides, the twist barrels are made of the best Norway iron and steel, welded together in spiral form.
Again, the writer referred to says twist barrels are no longer made. This is a mistake. All barrel makers make them, although the old stub-and-twist, which were made of old horseshoe nails, are no longer made. I have it from so good an authority as Mr. Josette, of Pagnoul & Josette, the barrel makers of Liege, Belgium, that the twist or Damascus barrel will stand a much greater strain than the decarbonized steel (iron) barrel.
Anyone who frequents the Northwestern duck fields will see that many more cheap blue barrels than twist are burst with the heavy loads used for ducks.
I pin my faith to an Ithaca twist duck gun, and feel safe with 4 drams of Dupont's smokeless.
Northwest, St. Paul, Minn.

Maybe not

Bessemer, Decarbonized or “Plain” Gun Barrel Steel reported tensile strength was about 63,000 psi.
Marlin Model 1898 Slide Action Shotgun “Special Rolled Steel” was reported to be 66,000 psi

I tested 2 decarbonized specimens: 66,000 psi and 71,500 psi

My Twist samples averaged 53,300 psi; Crolle 54,700 psi

Author:  RonRobinson [ Sun Feb 03, 2019 9:49 am ]
Post subject:  Re: Is my gun safe? What load was my gun designed to shoot?

Howdy ya'll, N/E central Ga here. Just aqquired a Bridge Gun Co 12 gauge single with "choke" marked
on top of barrell, serial # A640503. Stock has a few dings, beauty marks, barrell has blueing still on,
bout 70% of barrell still blued, hammer/ trigger steel no blueing but no pits either. The only defects
were front sight ball snapped off and firing pin return spring gone, replaced with ink pen spring, yes I
know... The barrell has a mirror polish so might have been dressed, maker and date would be apprec.
but real question was this gun designed to shoot meduim brass shells or should I stick with low brass?
And yes no steel shot will go thru her. Again maker and date would be nice... Blessings

Author:  Drew Hause [ Thu Feb 07, 2019 3:46 pm ]
Post subject:  Re: Is my gun safe? What load was my gun designed to shoot?

Bridge Gun Company was a tradename used on shotguns made for Sharpleigh Hardware Co. St. Louis, and were made by Crescent Fire Arms, Harrington and Richardson, and J. Stevens Arms Company.
Check this thread and you may be able to ID the maker ... 5&t=447782

The gun should not be used with any load until it has been evaluated by someone with the interest, equipment and expertise to do so. If the barrels have been honed, the smith needs to measure wall thickness from breech to muzzle.

Author:  Drew Hause [ Sat Mar 02, 2019 9:58 am ]
Post subject:  Re: Is my gun safe? What load was my gun designed to shoot?

British standard service loads and pressures 1924-1954

1925 - 1954 12g barrel flats marked with chamber length and 1 1/8 or 1 1/4 oz.
In 1925, the 2 1/2” & 2 5/8” 12g maximum service load was reduced to 3 Dr. Eq. with 1 1/8 oz. shot with a mean pressure of 3 1/4 tons by LUP = 9,800 psi by Burrard’s conversion of long tons to psi.
The 2 3/4” 12g max. service load was 3 3/8 Dr. Eq. with 1 1/4 oz. shot with a mean pressure of 3 1/2 tons = 10,640 psi. (Primarily for heavier “Waterfowl” guns)

Major Sir Gerald Burrard, The Modern Shotgun, Volume II, “The Cartridge”, 1955 3rd Revised Edition pressures converted from Long Tons/ Sq. Inch at 1”
Standard 2 1/2” 12g loads were 1 1/16 oz.
12g 2 1/2” 33 gr. Nobel Smokeless (3 Dr. Eq.) with 1 1/16 oz. - 7,885 psi
12g 2 1/2” 33 gr. C&H Smokeless Diamond (3 Dr. Eq.) with 1 1/16 oz. - 8,288 psi
12g 2 1/2” 31 gr. Smokeless Diamond (2.8 Dr. Eq.) with 1 1/16 oz. - 7,179 psi

(Loads were designed for an “observed velocity” - average velocity over 20 yards - of about 1,050 fps = modern 3’ from muzzle velocity of about 1200 fps)
…….Standard Load……..…..……Standard Service…..Max. Service
10g 2 7/8” 1 7/16 oz. 4 Dr. Eq……….9,296 psi………….11,984 psi
12g 3” 1 1/2 oz. 3.57 Dr. Eq…….…….9,632 psi…………12,320 psi
12g 2 1/2” 1 1/16 oz. 3 Dr. Eq………..7,952 psi…………10,640 psi
12g 2 3/4” 1 1/4 oz. 3 1/4 Dr. Eq…..9,296 psi…………11,984 psi
16g 2 1/2” 7/8 oz. 2 1/2 Dr. Eq……….8,624 psi…………11,312 psi
16g 2 3/4” 1 oz. 2 7/8 Dr. Eq…….….…9,296 psi…………11,984 psi
20g 2 1/2” 3/4 oz. 2 1/4 Dr. Eq……….9,632 psi…………12,320 psi
20g 2 3/4” 7/8 oz. 2 1/3 Dr. Eq……….9,968 psi…………12,992 psi
28g 2 1/2” 9/16 oz. 1 7/8 Dr. Eq…...10,304 psi………..13,328 psi
.410 2” 5/16 oz. 7/8 Dr. Eq……...………8,288 psi…………10,976 psi
.410 2 1/2” 3/8 oz. 1 Dr. Eq……..…...10,640 psi………..14,000 psi

Author:  Drew Hause [ Sat Oct 03, 2020 1:14 pm ]
Post subject:  Re: Is my gun safe? What load was my gun designed to shoot?

Thought I would add this information to the thread after finding this 1894 article in Forest & Stream

"Schultze" was one of the first smokeless powders, developed in 1862, and was first marketed in the U.S. by Von Lengerke & Detmold in 1887.
The American “E.C.” & “Schultze” Powder Company was established in Oakland, New Jersey in 1890, and was purchased by DuPont in 1903. DuPont Bulk Smokeless was introduced that year.

Forest & Stream, November 24, 1894
“Gas Pressure or Bursting Strain” ... =PA459&lpg
The proof-house charge of the American Testing Institution for a 12-bore gun develops a gas pressure of over 18,000 lbs. to the square inch. It is the same strain to which finished guns are put abroad. No gun would stand such a strain for any length of time. About 10,000 lbs. may be considered of touching the safety limit, and for some guns even is hazardous. A load giving about 8,000 lbs. pressure and less is better suited for the average gun and everyday use.
(The pressures were no doubt measured using LUP and modern transducer values would be 10-14% higher.)
Maybe this is where the frequently expressed 8000 psi load recommendation came from?!?

April 20, 1895 Sporting Life
“Shall Guns Be Tested?” ... 7/id/48142

July 27, 1895 Sporting Life
Call for Government Proof House for Nitro Powder Testing ... 7/id/48122

A.H. Fox 1911 Catalog
“Fox Proof Test means that every gun is tested with enormous over-charge according to the requirements of European governments.”
(Under the 1896 British Rules of Proof, if 6 1/2 Drams Curtis and Harvey's “T.S.” [Treble Strong] No. 2 and 1 2/3 oz. “soft” No. 6 shot was used for Definitive Proof, the pressure generated was [color:#FF0000]16,400 psi[/color]; if 90 grains = 6 1/2 Dram “E.C. No. 1” Bulk Smokeless Powder, 16,100 psi + 10 - 14% for either.)

From “Smokeless Shotgun Powders: Their Development, Composition and Ballistic Characteristics” by Wallace H Coxe; E.I. du Pont de Nemours & Co., 1927, p. 54
“It is generally conceded that a definitive proof should develop a pressure 25 to 40% greater than the service pressure to which it is expected the gun will be subjected.”

LTC Calvin Goddard writing in “Army Ordnance” in 1934, stated that Hunter Arms proof tested 12g 2 3/4” chamber barrels at 14,300 psi + 10 - 14%.

A Parker Service and Proof Load table was published in the 1930s and reproduced in the The Parker Story p. 515. 12g 2 3/4” shell Service Pressure is 10,500 psi. Definitive proof used 7.53 Drams Black Powder and 2 oz. shot with a pressure of 15,900 psi + 10-14%, or more than 17,500 psi.

LTC Calvin Goddard reported the same numbers in “Army Ordnance”, 1934. He wrote that Parker followed the SAAMI standards of that period: 13,700 psi proof, 9500 psi service for 2 5/8” chamber; 15,900 psi proof, 10,500 psi service for 2 3/4” chamber (by LUP) + 10-14%

Parker GHE SN 221278 1927 D3 3 Iron damascus with the "PARKER BROS. OVERLOAD PROVED" stamp which first appeared in 1925.


Ithaca advertisements stated that barrels were proved with a “double charge of powder and 1 1/2 times the normal shot load”; or (possibly) 6 1/2 Drams Black Powder with 2 1/4 oz. of shot if the standard load was 1 1/8 oz. shot and 3 1/4 Dram Eq.
Jack O’Connor wrote in Outdoor Life in 1942 that Lew Smith, President of Ithaca Gun Co. stated the Proof Loads were 17,500 psi + 10 – 14%

1911 Ithaca Gr. 1 Flues with "NITRO POWDER PROVED"


Modern 12g and 16g 2 3/4” and 3” SAAMI Recommended Proof Pressures ... tshell.pdf
If a manufacturer uses a SAAMI proof loads, then the gun will be proofed by a lot of no less than 10 shots of ammo loaded to a maximum proof pressure of 20,500 psi +/- 900 – 4600 psi, or uber max of 25,100 PSI; and, will be similarly a MINIMUM average proof pressure of 19,000 PSI +/- 900 – 4600 psi for an absolute minimum proof of 14,400 PSI.

“Definitive Proof Cartridges should be loaded with the heaviest shot charge used at the time of introduction and the slowest powder which will meet the pressure values indicated for that particular shotshell to maintain effective pressure-distance relationship.”
The powders used in proof loads are not specified on the SAMMI site

Author:  geometric [ Sat Oct 03, 2020 2:02 pm ]
Post subject:  Re: Is my gun safe? What load was my gun designed to shoot?

Mr. Hause:
As usual, you are a wealth of information. I will read it in more detail later but I have seen some of it. I am told that most blow ups are the result of barrel obstructions, as some of your data seems to indicate. Fortunately, I think you will agree, most guns will survive much more pressure than they should ever see. They usually start falling apart before they fail completely. However, it only has to dramatically fail once, as your photographs suggest, to ruin your whole day. I don't & don't suggest that anybody else should not take the precautions you recommend. Nobody ever got hurt from being cautious! Structures & guns are designed with what engineers call a safety factor. When I am dealing with something that can hurt or kill me, personally, I like a really big safety factor.
Thank you for sharing this with us!
I just realized how long this post has been going on! I apologize for repeating old material but it is a topic that is always of interest!

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