do not use archery ranges to train marksdwarves. Thralled semi-megabeasts, thralled blind cave ogres, and other thralled animals make excellent immortal targets that can be re-caged for clean-up and bolt removal when necessary.
That's something... although I actually use archery targets, I tend to use the following array of range:
###### ####
#_____...___#
#_X_X_ _X_# <- target end
#_+_+_..._+_#
#_+_+_ _+_#
(continues for 20..25 rows, and as many separate ranges side-to-side as I feel I want to set up..)
#_+_+_ _+_#
#_+_+_..._+_#
#_+_+_ _+_# <- end to fire from, with range area set to maximum possible for a bottom-to-top firing range.
#_>_>_..._>_#
##+#+# #+## <- entryways from corridor(s) outside the range area...
(sometimes just one entry, and floors between the downstairs on the above row)
# = wall (natural or constructed, smoothed or not, doesn't matter...
_ = channel (can be left as ramp, but best de-ramped at the target end)
+ = floor (natural or constructed, smoothed or not, again...)
X = Target
> = Steps down (if no ramps to do the job).
And on the level below I put a bolt (and arrow, if I have an arrow-firing squad) stockpile...
Ammo that doesn't hit the target (or, indeed,
any target[1]) hits a wall, falls onto the stockpile and is re-usable. Once a squad is consistently hitting a target[1, again] at this maximum they've done enough practice and they can develop further skills firing down on enemies from my fortification-lined walls and/or catwalks, rather than waste ammo (even of the training kind).
fakeedit: Ooh... @mobucks... never considered doing that... doubling up barracks/training area... I could possibly modify my above ammo-saver design to have a barracks all along the bottom (or whichever orientation) edge... Not that I appear to need it, but sounds like something to try in the future. Also, I always undo any Hunting assignments (not worth my time and effort, food-wise... and the risk of being ambushed, similarly no dwarf remains a fisherdwarf), but I've never zeroed the Hunting ammo setting, but I can see why it might be necessary if I'm generally low...
[1] For this reason, I sometimes debuild (or don't build in the first place) every other target, because really bad archers have a 50% chance of hitting any one of five or so of the archery targets that their often very off-target shots[2][3] might head towards... Lacking every other target increases my recovery rate for the less competent, but I still have to look out for them getting too good, and no longer needing the practice because they're hitting their own target and producing "broken ammunition" smudges instead of leaving recoverable training ammunition.
[2][3] The cross-section "#_X_#_X_#...etc" would overcome that. i.e. about half as many ranges, with walls left (or rebuilt) on the alternate "spurs" that don't have targets. I used to do that, but then started going for as many targets as possible for a particularly archer-heavy fort where I needed more training spaces. Swings and roundabouts.
[3] True story: When my Dad was doing his National Service (in a non-combat capacity, not exactly being A-1 in health), he was almost heading towards being qualified as a marksman. When they did the aptitude test at the firing range firing (say) ten shots at the target, his target had
19 shots within the appropriate 'pass' ring of the target (where all had to land to qualify), and one just outside. The guy next to him had been firing at the wrong target! Obviously there was no way of telling which of the two had made that one miss, but it was (unsuccessfully) argued that surely if a guy can't even hit the right
target, surely he'd be more likely to have fired a disqualifying shot as well...
Anyway, his Physical had already disqualified him from going off to whatever front-line the British Army was currently fighting, so I suppose it was not entirely a loss to the current war effort (unless maybe as a capable instructor?) for him to continue working only in the Administrative capacity that he was involved in.