My longest shot has been 350 yards, taken from a sitting position out in the middle of open sage no more than knee high. Closed the last 100 yards on my back, pushing myself headfirst through the sage, cactus and a couple inches of snow with my feet. We had been watching a herd of elk from a range of ~600 yards with no way to get closer until the elk started moving off their knoll at sundown. (Had I been prepared for a 600-yard shot, I would have had hours of low-wind conditions in which to make it.) The herd had started to move further away when I took the shot just a few minutes before the end of legal shooting hours - it was shoot or wait for another day. Didn’t have a laser rangefinder back then so a GPS with mapping software was used to calculate the distances after the fact.
Back then I rarely practiced at 300 yards and 400 was even more rare. Must have been enough, though, because the bullet impacted where desired. These days I spend more time at 300 and 400 and plan to spend more time at the 500- and 600-yard lines, places that have seen my shadow only a couple times. Given a good field rest and low wind I feel comfortable at 400. Part of my problem, and one of my limiting factors, is my rangefinder only goes to 400. It will do 500 on a really good target, like a house, but not in the field. As things stand, 400 is my limit.
A new rangefinder and more practice at 500 and 600 will change that. Last night I loaded up some .308 Win and .30-06, both with 168g A-MAX, especially for the 500-meter rams at Whittington Center, about 3-1/2 hours south of here. Need to load some 120’s for the .257 Roberts, too. (No centerfire .22’s of magnums allowed on the silhouette range.) I figure about 400-500 rounds total will be enough for my buddy and me, won’t be very many silhouettes left standing at any range, and we’ll have plenty for the paper target ranges, too. Need to get some more brass for the .30’s, and some more BL(C)-2...