I HAVE A NICE OLD STEPHEN GRANT 16 ga DAMASCUS CIRCA 1875 AND I SHOOT ONLY RSTs or my own low pressure handloads. from what I have read 16 ga pressures in "FACTORY" ammo run 9-10M psi.
and I worry about the buttstock abuse as much as the barrels.

I shoot all 2 1/2 inch low pressure and nothing over 1150 FPS in everything. In these older guns we all cherish I'm much more concerned with the stock as I know the barrels are safe.

In the last few years I've gone to 3/4 oz in the 20 and some in 16 but mostly 7/8 oz in both 16 and 12. Clay targets break and birds fall from the sky. It's also easier to acquire the second target or get a second shot at a bird with the lighter loads.

Thing about most factory 16 G shells, to sell they have to function A 5 Autoloaders. Those moving parts need recoil to work. Even more recoil if they are dirty.

William

I know what you mean about Auto 5s.

I lived in England in the mid 70's. If memory serves me correctly, Eley standard velocity shotgun shells were 1050 fps and their high velocity loads were 1175 fps.

I have a circa 1950s M 21, which is virtually indestructible. I shoot light 1 oz. loads in it. Why? Because my shoulder is attached to it while shooting. Same with my 32" VHE 12 gauge, go to gun.
What a lot of people don't realize is that at 40 yards, the load that starts at 1100 fps, is traveling at a very similar speed as the load that started at 1500 fps. The slower load likely patterns better, and recovery time to the second shot will be much faster.
Less wear and tear on the equipment is an added bonus.

I have a 1925 16 gauge hammer gun with fluid steel barrels with 2 1/2 in chambers. I fired one box of modern #6 hunting loads. Recoil was harsh and gun miserable to shoot. I switched to 2 1/2 in RST shells and love it. It’s my go to gun for upland birds. Lesson learned, buy the shells the gun was built to shoot.