Don, I have a VH 20 ga 28 inch with very little chokes. The more I shoot it the more I like it. Bill has opened chokes for me a couple times and did a great job in my opinion.

"A British shotgun proof rating of 3 tons/sq in (often seen as a "3 TONS" or "3" mark on older shotguns) equates to 6,720 pounds per square inch (PSI). Service pressure= 8939 psi."

David: did you mean a proof pressure of 16,720 psi? Is that by LUP or piezo transducer? Where did you find that number?

Under the 1925 Rules of Proof the Mean Proof Pressure for 12g 2 1/2" & 2 5/8" was 13,700 psi; Max. 15,000 psi
For 12g 2 3/4" Mean was 15,900 psi; Max. 17,500 psi
But those numbers are by LUP and require adding 10 - 14%

The 1954 Rules of Proof “Highest Mean Service Pressure” equivalent transducer values as converted from LUP by Burrard’s formula:
2 3/4 tons = 8,120 psi
3 tons = 8,960 psi
3 1/4 tons = 9,800 psi
3 1/2 tons = 10,640 psi
4 tons = 12,320 psi

Your 8939 psi is the conversion provided by the Birmingham Proof House 11-2001 (courtesy of Larry Brown) and is simply Tons x 2240 x 1.33

John Brindle, author of Shotgun Shooting: Techniques & Technology published a review of Proof and Service pressures in Part 5 of his series in The Double Gun Journal, “Black Powder & Smokeless, Damascus & Steel”; Volume 5, Issue 3, 1994, “Some Modern Fallacies Part 5”, p. 11.
His estimated post-1954 (TONS was marked 1954 - 1989 and was measured by crushers) but pre-CIP standard pressures converted to piezo transducer PSI

......................Standard Service....Max. Service.....Proof
12g 2 1/2”..............6,800 psi.........8,800 psi.......12,250 psi
12g 2 3/4”..............7,800 psi.........9,800 psi.......14,050 psi
(CIP 2 3/4”)...........10,733 psi........12,328 psi......13,489 psi
16g 2 1/2”..............7,300 psi..........9,300 psi.......13,150 psi
16g 2 3/4”..............7,800 psi..........9,800 psi.......14,050 psi
He did not record 20g

I've got a Sterlingworth Ejector that has made the swim across the pond and back, too.

Man, if these old guns could talk . . . .

https://www.jpgbox.com/jpg/75767_800x600.jpg

I took my new Parker and went kicking brush piles this afternoon looking for some cottontails. Didn't kick up any rabbits, but did spook one squirrel in the tree tops and Parker did what it was built to do. Back in business :)

https://i.imgur.com/UsgC21l.jpg

https://i.imgur.com/xFcQFtO.jpg

I took this gun up to Bill Schwarz a few weeks back for inspection and the slight rattle I detected was diagnosed as a cracked head stock. I left it with Bill and although it didn't have any visible splits he said I got it to him just in time. He was able to make a full repair, but said I was a few shots away from a major split / crack. I also had him lengthen the chambers to 2 3/4 which he recommended based on my planned use for this gun and also opened the right barrel to IC. I'm confident it will now outlast me.

I had a chance to shoot it some yesterday and I couldn't be more pleased. These targets are not particularly challenging, but I like this set when shooting a gun I'm unfamiliar with as it lets me judge how well the gun fits me and moves to the target. The lighting makes it hard to see, but I hit all of these targets including the following pair at the end of the video.

Short video:

https://www.youtube.com/watch?v=6xTtKgKK2ZY&t=26s