03-04-2017, 12:56 PM
topcaat1 Wrote:I have an ACOG with a BDC cross hair reticle for a 5.56 20 inch barrel. Works great on my 6.5 Grendel with a 16 inch barrell using 107 SMKs or 108 Lapuas.
Muzzle velocity is right around 2525 fps. Did have to sight it in 2.5 inches high at 100yds. Using the 100 yd. cross hair its pretty much dead on at 200yds. At 3, 4 and 500 yds it hits within a couple inches of the respective cross hairs, Thats within the margin of error for me using a 4X scope. Despite what my ballistic software says, for some reason it hits about 6 inches low at 600 yds. Think it must be a problem from when the scope was made. Hits on 8 inch steel plates are easy out to 400 and not so difficult at 500 yds. In the past I used 123 grain AMax at 2425 fps. Results were similar but it was hard on bolts and brass with my prefered powder.
Not sure I would go out and buy an ACOG now due to the price, but love it on this rifle. Bought mine prior to a depoyment in 2004 before the Corps issued them to everyone, and took it on my next deployment because I trusted it. Now it has sentimental value. I think possibly BDC for 5.56 or 7.62 carbine might match even better?
TC:
Not really surprising. Select a couple of common rounds of ammo and run them on a ballistics program that gives you a visual and numerical trajectory and compare them. You will find that to 300 yards, everything is very close. You may have an inch or so separating the least efficient to the most efficient. At 500 yards you will see some differences but for most situations, guys will still get hits on steel targets with the same hold or more centered hits with nothing more than a favor on the target being shot. Ballistically, you will see major differences when you shoot at 600 yards and farther. That is when you will either have to use full holds or use parts of the reticle to hold off. Hits become highly problematic, especially if you are holding off for elevation and windage. Thats why any of the 'Christmas Tree' or ballistic types of reticles like the ACOG will do just fine with the Grendel and any other cartridge to about 500 yards.
LR55