With the popularity of the AR platform and the .223/5.56 round I thought it would be a good idea to review the trajectory of the round and common sighting ranges. Being a high velocity round the trajectory is relatively flat within a few hundred yards – past 400 the drop-off is significant.
There are several philosophies on sighting in the AR and what range in best. Here are a few examples:
50 Yard Zero – Sighting in the AR to be on the money at 50 yards is extremely popular and typically what I do. Why? Because at 100 yards I will be hitting about 1.5″ inches high and at 200-225 I will be back on the money. This provides excellent accuracy from 0 out to past 250 yards with little if any compensation especially if we are talking about shooting man-sized targets.
This is by far the most popular method used for sighting in an AR.
100 Yard Zero – Not a bad option at all. With a zero of 100 yards, the .223/5.56 round will impact approx 3/4″ low at 50 yards and around 2.25″ low at 200 yards.
25 Yard Zero – I don’t care at all for sighting in at 25 yards. When zeroed at 25 yards the round will also be zeroed at 300 yards. This strategy does not provide much of an advantage unless longer range shooting is planned. The problem is between 25 and 300 yards where either the rear sight has to be adjusted for elevation while shooting or english used.
All these numbers are relative and depend on specific barrel lengths, loads, and barrel rifling.
What about 10.5″ barrels?
AR pistols are all the rage with the most common barrel length being 10.5″ inches. With a shorter barrel, a loss of velocity occurs which affects trajectory. The shorter barrel does not affect accuracy(look in the comments for disagreements). With the lower velocity and change in trajectory – I still like the 50 yard zero. If you are on at 50 yards – you’ll be approx 1″ high at 100 – and 3″ inches low at 200 yards. Your mileage may vary.
Stack ’em high and stack ’em deep!!
JR
* * * * * * * * * * * * *
