Sterlingworths are among the strongest of the early 20th century American doubles, and I would not hesitate to use Wally World promo field loads in it. Rem Game Loads, Win Super-X, Fed Field & Range, etc., should be fine. I'd stick to 1 oz. loads and avoid 1-1/8 oz., but I do that on modern guns too. Lots of guys use Sterlys as waterfowl guns with heavy loads. If it's tight, on face, wood not oil soaked, etc., go for it. This is a no brainer.