Well, target shooting gives us kind of a baseline. And we can assume it usually goes down from there (which is something you can quantify in a game, all the factors which make it harder). But shooters who could do much better than the average were a known quantity and played an important role in a wide range of well documented battles.
There is also different kinds of circumstances for shooting. If you are involved in a fairly low-intensity siege, of the type which were very common in medieval and early-modern times, especially if you are one of the defenders, shooting at encroaching enemies through some aperture in a thick stone wall, at your leisure, and going back at the end of the day to sleep in your own bed, your actual battlefield shooting may not be that far off from your target shooting, especially if you did a lot of the latter.
One of the biggest differences between armies in the medieval period vs. those in the later early-modern, is that the former – at least in the case of burghers- did indeed invest in their own powder and weapons, as it was a requirement for their citizenship. And not only that but they spent a great deal of time engaging in these various martial sports. The same was true for the other estates as well. Anyone (any male) with some degree of freedom who wasn’t a Clerk was probably spending some time in their life preparing for an dealing with weapons, and probably involved in some martial sport or warlike game. And, depending on their estate and rank – armor, horses, supplies, and all kinds of other gear.
By the later 16th Century an increasing number of soldiers are being recruited from very poor areas (Black Forest in Swabia, Estremadura in Iberia) and trained in a somewhat systematic fashion in the manner of Landsknechts, as established by Max I with the help of Swiss officers and feldweibel. These people did not necessarily bring anything to the table except a willingness to fight for the kings schilling, but they didn’t need nearly as many of those (schillings) to fight, and thus far more of them could be recruited into the army.
