Other than RST, who caters to the vintage gun/low pressure crowd, no ammunition manufacturer is going to tell you want the chamber pressures of a given load is.
They will only tell you that the loads are according to SAAMI spec. Which is a max pressure for a given gauge.
Likely because this leaves them open to the possibility of component changes which could change pressures along the way.

I once gave Federal a call in order to ask what the PSI was on their Estate Super Sport Competition loads in 1 1/8 oz. 1145 FPS. However, I did not receive any definitive answer. Just that they were right around 10,000 PSI. I seem to remember that Tom Roster in an article once said that there was no correlation between lower feet per second loads and low chamber pressure in modern loads. I agree whole heartedly that RST is the only manufacturer that really caters to the vintage shooter who definitively needs low PSI loads.

Exactly right on the fps and pressure correlation. Just look at reload data and you will see it is all over the map.

One thing to keep in mind when discussing the big ammo manufacturers is they must make there product with the auto loader in mind. If it does not have the pressure to operate those guns they lose a large segment of the market. So I assume the pressure is up there until proven other wise.

The pressures of the discontinued Herter's shells (I think by Cheddite) were surprisingly just below the SAAMI recommended max. of 11,500 psi; likely loaded with very fast burning powder.
As stated, only independent pressure testing can give the pressures of the new Herter's.
Tom Armbrust's contact is:
1108 W. May Ave.
McHenry, IL 60051
815-451-6649
Payment is by check only, and the shells must not be shipped by USPS.
If you send shells, please share the results with us!

A few factory load pressures are at the bottom here
https://docs.google.com/document/d/1...UOZEFU/preview

So Drew, if I'm reading that correctly it looks like between 1900 and WW1 they were shooting field and target loads generating pressures between 8,000 and 11,500 psi?

That is correct John. But some fellas pushed the envelope a bit :eek:

Kansas City, Oct. 23 1897
A remarkable exhibition of live pigeon shooting was given at Exposition Park, this city, yesterday afternoon, when Fred Gilbert, of Spirit Lake, Ia., and J.A.R. Elliott, of this city, met in a match at 100 live birds for $100 a side and the DuPont trophy, which Elliott won from C.W. Budd a few weeks ago with the score of 99 out of 100. The match was for the DuPont trophy at 100 live birds each man, 30 yards rise. Gilbert and Elliott tied at 97, then Gilbert won 25 to 24 in the shoot-off.
Gilbert used an L.C. Smith hammerless gun, 3 3/4 drams DuPont smokeless powder, 1 1/4 oz. No. 7 chilled shot in Winchester Leader shells.
J.A.R. Elliott used a (7 1/2#) Winchester repeating shotgun, 3 1/2 drams “E.C.” powder, 1 1/4 No. 7 1/2 and 6 chilled shot; Leader shells, loaded by Winchester.

1 1/4 oz. 3 1/2 Dr. Eq. BULK Smokeless was about 11,500 psi; the modern SAAMI max. for 2 3/4" 12g
and 1 1/4 oz. 3 3/4 Dr. Eq. (1330 fps) in an 8# shotgun = 29 ft/lbs free recoil
1 1/8 oz. at 1200, (3 Dram) 7.5 # shotgun = 23 ft/lbs of free recoil

Gilbert was shooting a hot load! And it paid off.

Independent testing of Cheddite for Herters 16g “Select Field Dove and Quail” 1 oz. at 1165 fps showed pressure averaging 12,500 psi with one at 13,400 psi.

Nah. Now THIS is a hot load :shock:

October 19, 1895 Sporting Life
Dr. J.L. Williamson, of Milwaukee, Wis., has just purchased a new gun of more than ordinary proportions. The Doctor was quite taken with Carver's Cashmore gun, having long barrels and shooting a big load in a 3 1/4 inch shell; but desiring to give the American gunmakers a chance he ordered a gun from the Lefever Arms Company, of Syracuse, N. Y. but at the same time rather doubted their ability to make such a weapon as he desired. However, the gun was furnished and Dr. Williamson killed 79 out of 80 live birds on one trial, and 74 out of 75 targets, part being doubles.
The gun is a Lefever, 12-gauge, weighing 8 1/4 pounds, 32-inch barrels, and chambered for a 3 1/4 inch shell, and guaranteed to stand 4 1/2 Drams of “E.C.” powder, which is the amount of powder which he uses.

(1 1/4 oz. with 3 1/2 Dram “Schultze” was about 12,000 psi. “Schultze” pressures were somewhat lower than “E.C.”)

He did not compete in the 1896 GAH at Live Birds, but held the “E.C.” Cup that year; his gun was not listed
https://digital.la84.org/digital/col...id/47243/rec/7
https://digital.la84.org/digital/col...id/46882/rec/5

He used a Cashmore with 1 1/4 oz. 3 1/2 Dr. Eq. DuPont Bulk at the 1897 GAH at Live Birds, and was one of 5 competitors with 24 kills
https://digital.la84.org/digital/col...id/45852/rec/4
https://digital.la84.org/digital/col...id/46498/rec/3