doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com pressure rating for 1220 12 ga ammo

Federal and Herters each sell 3-1/4x1-1/4x 1220fps shotshells an old standby. What is the psi rating for these?

Below SAAMI max.

Best,
Ted

The only way to know is to send samples for pressure testing and pay the toll. And, after you get the results you will only know what the pressure was for that particular lot. Next lot may, or may not, be different.

As said, only the makers know, and they aren't sharing
I've never seen independent testing for the 1 1/4 3 1/4 loads

For a historical perspective, from “Smokeless Shotgun Powders: Their Development, Composition and Ballistic Characteristics” by Wallace H Coxe; E.I. du Pont de Nemours & Co., 1933, for a 3 Dr. Eq. 1 1/4 oz. load.
Pressure by modern piezo transducers would be 10-14% higher.
DuPont Bulk = 9,600 psi
FFFg = 9,000 psi
DuPont Oval = 8,700 psi
DuPont MX = 9,800 psi
DuPont MX Smokeless was a Dense Multi Base Powder introduced about 1928. 25.5 grains was 3 Dram Eq. and it was promoted as a 1 1/4 oz. Trap load. It was replaced in the 1954 with IMR PB.

IMHO it is safe to assume a modern 3 1/4 Dr.Eq. load pressure would NOT be any less.

A Winchester Reloading Manual (I don't know the date or if the pressures were crushers or piezo) listed that load with WSF at 9000 psi
https://www.appuntidiricarica.com/pluginAppObj_120_24/Winchester-Reloaders-Manual-.pdf

The replies from Ted and Stan were the only ones that came even close to answering the OP's question.

Specialty ammo loaded to lower pressures seems to almost always be more expensive than standard SAAMI spec ammo. So it would seem to benefit ammo makers financially to disclose pressure data for each lot they produce. Archaic terms such as Dram Equivalent mean little to the average shooter. There is no question they test their ammo and have that data. There is no question that they do more testing anytime they change powder, primers, or other components, just out of product liability concerns.

Or maybe they don't give us a thought, since the segment of the market that wants lower pressure ammo isn't large enough to get their attention. And maybe that situation could change if enough of us requested it from the source... instead of asking people who just don't know.

I looked through an Alliant reloading manual for that load, and with 20/28, Unique, Herco & Blue Dot the pressures ranged 9000 - about 10,000 psi.
IMHO it is very unlikely that non-specialty loads (or B&P) would be LESS than 9000 psi.

Was not aware that the Herter's tradename is now owned by Bass Pro-Cabelas and the shotshells are by Winchester; which of course may change as can components & powder

Some time ago I contacted Remington, Winchester & Federal regarding 16g pressures and no one responded. The only way to have factory loads tested today is by Tom Armbrust.

re: SAAMI recommended standards, but NOT carrying the force of law like CIP standards.
SAAMI allows the maximum average pressure for 12 gauge 2 3/4” and 3” shotgun shells to be 11,500 psi +/- 900 psi, with the maximum extreme variability not to exceed an uber-max of 12,500 psi +/- 900 psi or 13,400 psi.
CIP 12g 2 3/4" Maximum Statistical Individual Pressure is 850 BAR = 12,328 psi

Keith,
I’m guessing that the manufacturers of shotgun ammunition know, exactly, what pressure is produced from every single loading they produce. They know exactly which components affect that level of pressure, and why. I’d bet there is far more testing of loaded ammunition than we would have guessed.

That said, there is exactly zero evidence to suggest that sharing that information with the end user would be a benefit to them. Leaving the answer to the question at “below SAAMI max” puts any and all responsibilities for the use of that ammunition on whoever bought it. They tell you straight up it could be the hottest stuff that they can get away with loading, and it is totally up to the consumer to make sure his equipment is up to it. They will be no “he said” in a courtroom when somebody guesses wrong on what they can get away with on their antique gun.

If somebody has a requirement for low pressure ammunition, they had better be sure they source low pressure ammunition for that requirement. I am stunned at the guys who are willing to take a guess that some off the shelf ammunition will be what they need for their old gun. Guys who I figure should know better, do it right here, all the time.

Best,
Ted

OK, Ted, does this mean my flats of “low brass” might be suspect ?

Well, yea.

I don’t test ammunition, but, in casual conversation with a few production people employed at Federal Cartridge, right up the road from me, promotional ammunition is the most inconsistent and features some of the highest pressures. How inconsistent, and how high pressure, is known by a lot fewer people than you would think.

Best,
Ted