09-14-2014, 11:39 PM
rwh Wrote:I was confused by the way this thread started out as a comparison of grendel in AR15 vs 308 in an AR10 followed by a comparison of a 308 bolt gun shooting hand loads to a grendel shooting factory ammunition.
That seems to cause heartburn for everyone. A buddy of mine has an 18" OBR in 308. I'll try to get it and do some testing with factory loaded ammo to get a closer comparison.
I was also thrown by the big difference between the trajectory I got from Sierra Infinity Suite compared to what bigbear_98 was getting from the JBM ballistics engine.
[COLOR="#4169e1"]That is something I notice and see posted a lot. Data that just doesn't seem "right". Everyone trusts what the calculators say. They just predict.
I shot both of these rifles out to 1200 yards at an Accuracy first class. I had the Ballistic AE app, my whiz wheel (I had already gotten the data from a chrono set at 10ft, 100 yards, and 200 yards), and the Kestrel with Applied Ballistics all side by side. The apps gave the yardage our rounds were estimated to be subsonic at, then we shot to get a true data point. Eventually all of the calculators were reading the same. Everything is dead on now.[/COLOR]
I think it is time to retire Sierra Infinity as JBM confirms what I've suspected all along, which is that getting a grendel to shoot to 1000 yards, while possible, is roughly equivalent to trying to get an M1A to shoot out to 1000 yards. Both can do it, but neither is ideal.
We were hitting 12" gongs at 1200 yards. If the rifle is shooting tight, the round is capable of getting there. I am anxious to try some handloads tailored to my rifle.
I've been playing with the idea of an AR10 build, but I would probably not go with a 308 in an AR10 either. I was thinking 260 remington or 6.5x47 lapua. I would be interested if anyone has any data on how an AR10 does with hot loads. What parts on the AR10 are going to start breaking as I begin pushing loads up close to max for the cartridge. Is the AR10 really able to push the same kinds of loads one would use in a bolt gun?
Someone else will have to respond as I have no real world experience with an AR10 or larger 264 cartridges.
Very nice shooting.
Thank you.
I do love shooting.