I read this on the link listed below. This test was done with a 20 inch barrel. Where can I find similar info for a 16 inch barrel? Is this a fairly accurate way to zero my new AR 10? What short range do I zero in at to get spot on (or close) at 200 yards?? Is there a formula for this??
Sorry for all the questions. I'm curious.
Moby
We tested this Armalite AR-10 late one afternoon at the Freeport range on Long Island. We were limited to shooting at 50-yards. That said, sighting-in a 7.62 x 55 NATO M-14 or AR-10 weapon is easy and rewarding; a 20-inch barrel firing a 30-caliber round yields fairly flat shooting results. Most of the cognoscenti know that by zeroing-in the weapon at 45m, the ballistic curve determines that it is also zeroed again on the backside of hte slope at 200m, with a midpoint of approximately 1.5-inches high at 125m or so.
Bottom line: by setting our sights for 45m, we could determine what this weapon would produce at 200m.
Zeroing at 50m is a pretty standard way to zero a fighting rifle whether it has a 14.7", 16" or 20" barrel. The mainstream military tends to use a 25m/250m BZO system, which isn't bad but yields rougher results at ranges beyond 250m. If you have an AR10/.308 AR carbine, zeroing at 50m should get you on the target at 200. Try looking for scaled targets, they'll help you get an idea of what your rounds are doing at distance.
moby-
I suggest you shoot 100yds for testing your loads, sighting-in, etc..
Your gun should shoot 1.5" groups at 100yds, draw a circle around your groups and the center (average) is where you reference your point of impact (POI)..
if you set your sights to be 2.5" high at 100yds, your (POI) will be 1.5" high at 200yds. This will put you about 1.5" low at 300yds..
this is just a rough estimate pulled from a geezer with poor memory
sansone wrote: moby-
I suggest you shoot 100yds for testing your loads, sighting-in, etc..
Your gun should shoot 1.5" groups at 100yds, draw a circle around your groups and the center (average) is where you reference your point of impact (POI)..
if you set your sights to be 2.5" high at 100yds, your (POI) will be 1.5" high at 200yds. This will put you about 1.5" low at 300yds..
this is just a rough estimate pulled from a geezer with poor memory
These seem to be the same results I get with NATO stamped surplus ammo out of my 20 inch. I hope I can make some hand loads do the same thing with the same accuracy!
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