Kevin they are 2 1/2" 1200fps 1oz loads. They shoot very nice. The box is marked simply A5.

On the home page of RST website it says....

Our shells are safe to shoot in Vintage Guns. Even with Damascus and Twist Steel barrels!

Of course after a reputable SxS gunsmith has given the OK.

(With the exception of the Pigeon loads, A-5, Heavy Hunting)



So, the A5 shells, probably not a good idea in "some" vintage guns.....

We have good data for the pressures of turn-of-the-century 1 oz. 16g Bulk Smokeless Powder loads
2 1/2 Dr. Eq. (1165 fps) was about 7000 psi;
2 3/4 Dr. Eq. (1220 fps) about 8500 psi;
3 Dr. Eq. was about 10,000 psi
Dense smokeless would be higher.

IMHO if barrels, after a proper evaluation, are felt to be unsafe at 8000 psi, they are likely unsafe with any hunting or target load.

I own model 11 Remingtons same design as the A5. The recoil operating action is dependent on recoil not pressure. A standard 1 1/8oz load never is an issue. Light loads under 1 1/8oz causes problems.

Years ago when I reloaded a lot I "developed" my own 1 oz. target load for the 12 ga. A-5 by reloading successively lighter powder charges and shooting individual samples of each to try to hit the "sweet spot" in recoil that would operate the action properly. Using the older (better) style Win. AA case, 16.5 gns. of 700X and a Claybuster wad I got an 1195 fps. load at 9000 psi. This load data fits well with Drew's quoted 2 3/4 Dr. Equivalent figures. With proper friction ring adjustment they were a very nice load to shoot.

7/8 ounce and light 1 ounce loads were never meant for squareback Brownings or Remingtons. When you get down to 7/8 ounce loads or low velocity 1 ounce loads, you should modify your rings to lessen the friction. I do it by sawing a friction ring in half and reinstall one half. You then have two rings that can be used in two guns. It has worked for me for many years.