Best factory load I've ever used is the B&P F2. Their #5 is actually US #5.5. Swats phez out there. Think payload is 1 1/16 or 1 1/32 oz. Whatever.
For a second load, more obtainium and good for short/medium ranges (grouse/WC), like the Rem RGL.
For targets I load 3/4 oz and 7/8 oz using Red Dot and Green Dot, respectively.