Here's a round up of 16ga shells.
http://www.16ga.com/cartridges.html You can give the manufactures a call for pressure specs, sometimes they are helpful, B&P lists their pressures.
I don't know why but the 16 ga link doesn't have RST listed. RST makes 16ga in: 3/4 oz @1100 fps, 7/8 oz @ 1125 fps & 1oz @ 1200. All are 2 1/2" length and appropriate pressure for vintage guns.
I have a 16 that weighs right at 6 lbs & I prefer not to shoot anything heavier than 1 oz loads in it because of recoil & I usually shoot 3/4 oz or 7/8 oz in it for any type of clay targets to keep the recoil as low as possible where a lot of shots are fired.
If you have a 16 ga that is more in the 6 1/2 to 7 lb. range then the B&P 1 1/16 oz or any of the 1 1/8 oz loads of appropriate case length & pressure should work for you.
