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

I don't recall M. McIntosh making the quote about damascus that was attributed to him.
Good article.

Best,
Ted

I do not believe McIntosh made that statement either and I have read about all of his material.

I was at a well-known quail plantation recently and they include a prohibition against Damascus barrels in their safety rules - it is amazing how the myth perpetuates.

The article talks about pressures associated with CB1078-20 wads. I have found that the RXP-20 wads produce significantly lower pressures (at least out of WinAA hulls with Unique powder).

Interesting article perhaps.

Not a particularly good one.

The misquote of MM likely should be attributed to O'Connor.

If you can make recoil operated guns work with a specific lower pressure load, you likely can make a 391 work with it also. Lower max chamber pressure does not necessarily translate to lower pressure at the barrel tap point on a gas auto. 7,000 psi is not an absolute, and I know of at least two 391's in regular service with 7/8 oz target loads which have pressures below this often quoted minimum for reliable functioning. Supporting pressure curves are posted here with some regularity.

Too bad that any article like this now has to be so full of lawyer-speak. That takes away most of the pleasure of reading it.

I do recall McIntosh making that statement or one similar to it with the same meaning. Don't ask me where, but he did indeed say it. It seems to me he said it in a magazine article, most likely Sporting Classics, SSM or DGJ, all of which I subscribe to in which he wrote.

"It makes sense to me a gun hammered with 11,000 p.s.i. breech pressure will be stressed more than one coddled with 7,000�p.s.i. ammunition."

OK, Ron, please explain it so it makes sense to me, too.

Should I stop using my 3/4 ounce load that generates 11,000 psi and start "coddling" it with 1 & 3/8 ounce at 7800 psi?

The 1 &3/8 generates 3 TIMES the recoil energy, but with lower pressure it will be less stressful, right?

Looks to me like the author and editors spent more time covering themselves in legaleze than imparting any useful information.

I don't believe that was originally a McIntosh quote, but from a letter Lou Smith sent to a customer inquiring about one of Ithaca's old Damascus barrel doubles. From the days when the industry was perpetuating that Damascus & Twist barrel myth to try and sell new guns in the Great Depression.

FWIW, the inside flap of every box of RST ammo I have from their lightest 5/8 ounce 2 1/2 inch 28-gauge load to the heaviest 12-gauge 2 3/4 inch Pigeon Loads carries the warning "To prevent injury to shooters or bystanders use only in modern shotguns (not in Damascus twist barrels, etc.)...." The lawyers carry the day!!

From the late 1890s to well after The Great War, the heaviest 12-gauge bulk or dense smokeless powder loads our North American ammunition manufacturers offered were 1 1/4 ounce of shot pushed by 3 1/2 drams of bulk smokeless powder, such as DuPont, E.C., Schultze, Dead Shot, etc. --



or that same 1 1/4 ounce of shot being pushed by 28-grains of dense smokeless powder, such as Infallible or Ballistite --





offered in 2 3/4 inch and longer paper hulls. A couple of DuPont Smokeless Shotgun Powders booklets in my collection from the late 1920s and early 1930s state that the pressures of these loads were in the 11700 to 12600 pounds range.

Yep, unwarranted assumptions. Just like the quail plantation's ban.

He does mention the most frequent cause of bursts as obstructions, and that's no doubt accurate.

The second most frequent cause is undoubtedly improperly loaded shells, not weak barrels incapable of handling standard pressure.

Note that I didn't say improperly reloaded shells. It matters not who does the loading as in the case of the new Italian made and proofed gun that blew with factory shells. No, you won't hear specifics since the man's 'settlement' prohibits him discussing it.

Shotshell Pressures c. 1895-1930s

Black Powder
3 dram / 82 grains 1 1/8 oz. (1200 fps) is about 5000 psi.
3 3/4 dram GOEX FFFg with 1 1/4 oz. (1240 fps) is about 6000 psi.
4 drams of FFF (about 108 gr) with 1 1/8 oz. (1420 fps) is about 7000 psi.

Bulk Smokeless
NOTE: Pressures reported were determined by lead crushers and modern piezoelectric transducer measurements would be about 1000 psi higher.

�1895 Smokeless Powders For Shotguns�
http://books.google.com/books?id=Wv0MAQAAIAAJ&pg=PA446&lpg
3 1/4 Dram/40 grains DuPont Bulk Smokeless 1 1/8 oz. = 7440 LUP
3 1/4 Dram/44 grains �E.C.� Bulk Smokeless 1 1/8 oz. = 7584 LUP

The 1933 edition of �Smokeless Shotgun Powders� by Wallace Coxe and E.I. du Pont de Nemours & Co. reported the LUP pressure for 3 Dram Eq. with 1 1/4 oz. of DuPont bulk smokeless at 9,600 psi.

Coxe previously reported 3 1/2 Dram Eq. 1 1/4 oz. loads:
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

In a 1927 Western Cartridge Co. flyer "Super-X The Long Range Load" by Capt. Chas. Askins the 12g duck load is described as 38 1/2 grains or 3 1/2 dram (powder not specified but likely DuPont Oval) with a breech pressure of 3 3/4 tons or 11,480 psi.

Dense Smokeless
See 28 grains Ballistite above; well over the modern SAAMI maximum 2 3/4� and 3� 12g pressure.
Winchester Leader 1 1/4 oz. 3 1/2 Dram loads listed �Mullerite�, 3 1/2 Dram Dead Shot (Bulk Smokeless), and 28 gr DuPont Ballistite. Record 1 1/4 oz. loads also listed 28 gr Ballistite.

The 1963 George Herter �Reloaders Handbook� lists 23 grains (3 1/4 Dr. Eq.) of �Infallible� Dense Smokeless, now Unique, with 1 1/8 oz. shot in a paper case with paper wads (card & fiber) at 8,725 psi by LUP. (Courtesy of Mark Ouellette)

More infro
https://docs.google.com/a/damascusknowle...ZhIiY62Hx4/edit
https://docs.google.com/a/damascusknowle...fUOZEFU/preview