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Tom Roster on low pressure loads and vintage shotguns.

Glad I had my 1891 Ithaca NIG out yesterday for one last time.
(shooting 3/4 oz, 1150 fps, 6200 psi hand loads)

https://shootingsportsman.com/pressure-vs-recoil/

So, Tom, how does the gun know if the load generating 7000 psi is a smokeless load or a blackpowder load ............hmmm?

SRH

I stopped caring what Roster thought a long time ago. Probably when he said steel killed ducks better than lead.

Sounds like someone is getting some free stuff for advertising!

That�s some pretty good fearmongering without much more than vague anecdotal heresay as evidence.

After a phone call with Tom a few years back about a test he did years earlier that proved, and quantified, pellet setback damage in lead loads to be varying according to the location of the shot in the payload, I came away with the distinct impression that he had gotten pretty full of himself. He was not the gentleman, on the phone, I expected him to be. Maybe he was just having a bad day, or maybe I was just too naive, but I'd not call him again.

SRH

A fact based rebuttal of sorts, with some wandering into physics 101, and contributions from Randy Wakeman
https://www.shotgunworld.com/bbs/viewtopic.php?f=2&t=505616

Only 1100 views so Roster's propaganda is obviously getting much greater market penetration.

1897 "FOR BLACK AND NITRO POWDERS"



1911 No. 1 Flues "NITRO POWDER PROVEN"

For those with American vintage guns, it's probably good to remember that in the early days of SAAMI, which came into existence in the mid-1920's, there were different proof pressures for guns with short chambers vs those with 2 3/4" chambers. Hunter Arms proofed their 2 3/4" 12's at 15,900 psi and the 2 5/8" guns at 14,300. (Also worth noting here that what was recorded as psi back then--and this information is from the mid-30's--was actually LUP. Pressure testing back then was still done with lead crushers vs the current transducers.)

Re CIP proof testing, anyone interested in doing that needs to be aware that the British proofhouses may still be reporting the pressures at which they proof their guns in LUP rather than psi. They were still doing that back in 2001, when I communicated with the Birmingham proofhouse. Fortunately, when it was clear that there was a misunderstanding, they converted the proof pressure in question (and the appropriate service pressure, which is even more important) to the American transducer equivalents. Their proof laws have changed since then, and we may now be speaking a common language. But anyone having a gun proofed in the UK would want to make sure of that. They may give the pressures in (metric) bars rather than psi, but if you're going to convert from bars to psi as measured by transducers, you need to make sure that they're talking transducer bars and not lead crusher bars--which they were still doing back in 2001.

Wakeman might be worse than Roster. He has opined that our damascus guns should be illegal.

This document states that the pressures are transducer BAR converted to PSI. Maybe the British are complying
https://www.scribd.com/document/97965210/CIP-Shotshell-Pressures

Somewhat stunning that the Tons to PSI conversion provided to Bro. Larry by the Birmingham Proof House in 11-2001 was simply Tons x 2240 x 1.33 and not measured.
I guess the Masters thought the numbers were close enough for us Colonials
2 1/2� / 3 tons = 8,938 psi
2 3/4� / 3 1/4 tons = 9,682 psi
3� / 3 1/2 tons = 10,427 psi
3� / 4 tons = 11,917 psi

Mr. Roger Hancox, Proof Master, Birmingham Proof House, 2008.
A basic �Rule of Thumb� conversion of tons to CIP transducer pressure (is) multiplying the tons per sq inch by 2240 to obtain psi, and then by a factor of 1.33 to obtain the approximate CIP pressure.