iwantadouble:
Seems Mac is being a little harsh here. If your pictured group is OFFHAND at 300 YARDS, and those squares are inches, then its probably not too bad. Further, a 5-inch group OFFHAND at 100 yards is quite OK too IMHO, especially with open express sights as for most doubles. Remember, a 5-inch group means that NO shots are more than 2 1/2 inches from the point of aim, and in fact only the flyers are 2 1/2 inches away, most of the group will be closer. At 100 yards with open sights, that is perfectly acceptable accuracy, and probably as good as any of the posters here could regularly achieve anyway.

Of course, over sandbags at the bench is a different matter, and we might even expect a little better than 3 or 4 inches at 100 yards, but the reality is that open express sights and the human eye will probably not achieve much better than this, even in perfect conditions.

There's a lot of nonsense written about accuracy, especially in regard to double rifles, but they are not target arms so most of it is just crap. The term "hunting accuracy" was coined for a reason. Doubles are hunting rifles. Simple stuff really!