doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Interesting article on Old Guns and Pressure

Drew,

Do we know whether they were aware of the disparity in the units and used a "fudge factor" to guesstimate psi, or did they just use the terms interchangeably at that time?

Mike, I'm anxious to see Drew's response. However, I'm in possession of a magazine article on pressure testing (either "Army Ordnance" or "The American Rifleman, don't recall which--and I'm still unpacking stuff from a move) from the 1930's. All the pressure guns illustrated--and there are several, used by various companies--were of the crusher variety. Therefore, I've always interpreted anything from that era expressed as psi as being LUP--simply because everyone THOUGHT they were getting a reading in psi. I don't believe the term "LUP" even existed back then. (I'd be interested if someone could prove otherwise.) LUP is simply shorthand for a pressure measurement taken via the crusher measurement and originally expressed as psi.

Wish we knew Mike.

I believe Coxe reported the 3 1/2 Dram Eq. 1 1/4 oz. load pressures in 1928. Researcher would know
DuPont Bulk smokeless powder - 11,700 psi
Schultze Bulk smokeless powder - 11,800 psi
28 grains of Ballistite - 12,600 psi
40 grains of DuPont Oval Progressive Burning powder - 9,400 psi
It is my opinion that these are likely transducer numbers since 28 grains of Ballistite is already well over modern SAAMI 12g 2 3/4" and 3" maximum of 11,500.

I have the 1931 booklet in which this graph appears. "The vertical line represents the pressures developed by the various powders. This is measured in long tons (2240 pounds)."
It does not state HOW the pressures were measured however.



Charge was 1 1/4 oz. Dram eq. was not specified but was likely near Maximum. Using the estimated 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 1/2� was 4.5 Long Tons = 14,000 psi

This graph appeared in the 1933 booklet and is PSI. I don't have a copy so can't say what technique was used but Miller and Bro. Larry debated this issue here not long ago.



DuPont MX Smokeless was a Dense Multi Base Powder introduced about 1930. 25.5 grains was a 3 Dram Eq. and it was promoted as a 1 1/4 oz. Trap load. It was replaced in the 1954 with IMR PB.

Eureka! I guessed the right box of as-yet unpacked stuff from our move and found my files. As a result of which I now have my original sources at hand, and can comment as follows:

1. Pressure readings from the early 1930's. The American Rifleman, Sept 1931, included an article by Merton A. Robinson, ballistics engineer, Winchester Repeating Arms Co. Title: "Standard Shotgun Pressure Barrels". The article describes quite thoroughly the crusher method of pressure testing, and includes photos of pressure barrels then in use by Peters, Hercules, Western, Remington, Winchester, Du Pont and Federal. Although the barrels are of somewhat different designs, they are ALL the old crusher barrels. Therefore, any pressure measurements they expressed as psi would, in fact, have been LUP.

2. The Damascus "myth": My files contain another "Rifleman" article: a 2-parter (July 36 and March 38) by A.P. Curtis, who had been in the firearms business since the mid-1890's with various firms such as Syracuse Arms, Hunter (superintendent and factory manager), Winchester (foreman of all barrel shops), Ithaca (general manager), and was with Iver Johnson as assistant to the president when he wrote the articles. The article is entitled "Advantages of Short Shotgun Chambers".

I think many of us realize that the Damascus "myth" was drummed into our heads (as was the short chamber myth) by virtue of the warning printed on shotshell boxes. How did that warning come to be? Per Curtis: "SAAMI, assembled in serious conference on March 26, 1937, passed the following resolution: 'That an appropriate warning label be placed on all boxes containing smokeless powder shells, cautioning the consumer against using them in short chambered guns and also in guns with Damascus barrels and guns not in first-class condition'." The motion was made and seconded by representatives of two powder companies. That same conference also passed a resolution requiring: "That all guns be marked so that the consumer will be able to tell the chamber length, as for example by marking 2 3/4 inch chamber etc." That rule seems to have been followed on guns with 2 3/4" or longer chambers, but not on those with shorter chambers. And Hunter Arms, for one, was still producing short-chambered 16's at that time. Anyone ever see one factory marked 2 9/16"???

Although we recognize that neither chamber length nor the material of which the barrels are made, in and of themselves, constitute danger to those who proceed with a certain amount of caution, the warning--given the time at which it was issued--makes a certain amount of sense. By then, the new Super-X and similar shells, which increased pressures, had become commonplace. At the same time, however, dozens of loads were readily available, in all gauges, that were made up in shorter shells, appropriate for short-chambered guns which had lower proof standards than were then current for 2 3/4" guns. And it probably would not have been a good idea to fire a steady diet of Super-X 2 3/4" shells through a short-chambered gun, whether Damascus or fluid steel, because you have both the greater pressure generated by a slightly longer shell, plus the greater pressure developed by a "hotter" modern load.

The result being, of course, the over-generalization that you should not shoot any longer hull (regardless of the pressure of the load) in any shorter chamber, and you shouldn't shoot any smokeless load in any gun with Damascus barrels.

Those of us who have participated here pretty much from the beginning, however, clearly remember that there was a very strong "Damascus roulette" contingent involved in our discussions. And that we still find those who think Damascus guns are generally unsafe, and who think any longer hull in any shorter chamber represents extreme danger. (Darn. I just shot 3 rounds of skeet this morning with a 2 1/2" BSA 12ga: 2 3/4" Remington hulls, Extra-Lite powder, 7/8 oz shot . . . and I still have all my fingers.)

My wife and I were at Rio Piedra about three years ago and Morrison Pines last week. Both use the same Quail Unlimited safety video that includes many good safety instructions but also says "no damascus barrels". Both Rio Piedra and Morrison Pines had no issue with me shooting my damascus barreled Joseph Lang from 1866 with non-rebounding hammers. In fact our guide, John, was only concerned about the fact that my gun was a hammer gun - it appears that some number of shooters bring grandaddy's old hammer gun and do not know how to handle a one safely.

Larry, Some years ago I owned a 'skeet' grade 16ga. solid rib model 12 that was both clearly marked 'skeet' on its frame and 2&9/16" on it's bbl. I shot the proper length Mexican Mfg. Remington 'Huntsman' ammo sold through K-marts at $38~$40/case [those were 20 box days, so 500 rounds in a case] until I couldn't get it any longer, then I let that gun go to a collector who had a lust I couldn't refuse. I doubt that ammunition was low pressure by any standard.

I agree w/your position that there wasn't any method available in those earlier times of measuring psi, rather it was interpretation and extrapolation and foggy, meaning some smoke & mirrors w/o any intent to defraud. It simply wasn't exact and sometimes got misstated as psi, which it clearly wasn't & resultantly misinterpreted.

Thank you Larry, and I forwarded this valuable information on to Randy Bimson, Director, Technical Affairs, Sporting Arms and Ammunition Manufacturers� Institute, Inc. He responded to my inquiry as to the origin of the shell box warning back in May. His office is in the process of electronically cataloging SAAMI historical documents, but he then had no knowledge of whether any published statements relative to the safety or use of Pattern Welded barrels exist. He also explained that SAAMI does not currently have a position on the use of smokeless powder ammunition in Damascus or Twist Steel barrels, but added �should you broach the subject with any of the SAAMI member ammunition manufacturers...the response would be unequivocally �Definitely not!�� (His emphasis)

Larry,

There were many 16 ga. Browning A5s that were barrel stamped 2 9/16". And most all were lengthened to 2 3/4" by gunsmiths in the 1960's.

I also have a whole box of 2 9/16" 16 ga. shells from that era.

SRH

Interesting how the range of pressures from 5k to 7k psi is considered safe. Why not 6800 or 7200 for the high end? Will several thousand 8000 psi loads cause catastrophic failure? I shoot my grandpa's 1915 16 ga Flues a bit with moderate 3/4 and 7/8 oz loads (6500 to 8000 psi at around 1220 fps). He hunted pheasants all over the Midwest with it and I'm pretty sure he fed it a steady diet of heavy, high pressure loads. This is an area where one should be reasonable, whatever that means. I think large shot weights and high velocity are much harder on old guns than moderate to high pressures.
Regards,
Jeff

Especially if you believe in the concept of 'proofing'.

My recently acquired Parker DH had, in recent times, a good many standard factory skeet loads run through it's damascus barrel set.

I consider it 'proofed' to 9,500 psi.

My 'service pressure' hand loads run 6,000 psi.

The trick, is to keep the shells sorted - they all look alike.