09-22-2014, 02:39 PM
Soo.... I guess I have some crow to eat here.....
I took my rifles out and shot Friday at 250,500,750,and 1000. Both rifles were rocking steel at all distances, until I tried to shoot the Grendel at 1000. Now I went back to my data, compared the whiz wheel with my Ballistics app, both said 41.5 minutes of elevation, but I really needed 44 minutes.
Well, This bothered me. I switched back to my 308 and shot. I found things on the berm to shoot. Lazed them, looked at the chart, dialed the elevation, boom and hit. This was true data here. The 308 data was on. 250, 254, 500, 508, 745, 750, 755, 1000, 1008. Everything I aimed at I could hit with the 308. good numbers.
Ok go back to the Grendel and try to refine it as I did the 308. 250, 500 good... Wait was That a little low? Yes. So I ran everything all over again. I ran a box test on my scope. Good data there. tracks a little off at the high end but not bad and I can account for it. (Vortex PST)
So then I Shot at all distances I could. Took note of the elevation that It actually took to be zeroed at that distance, and compared to the numbers I already had. Well It was different. Close, but different.
I then set my chrono back up at 200 yards. Same number.
So I start to play with the BC of the bullet. I ran it down.... Way down.... And got the numbers on paper to match what I was really seeing. I kept the 200 yard velocity the same, lowered the BC, and raised the muzzle velocity.
Now I did all of this at a 3000 DA, so I am curious to see if it changes with the atmosphere, but It is exactly true right now. It is so true that, believe it or not, I couldn't miss with elevation. Wind was light, but enough to push 1-2 minutes, but elevation was perfect.
I took my rifles out and shot Friday at 250,500,750,and 1000. Both rifles were rocking steel at all distances, until I tried to shoot the Grendel at 1000. Now I went back to my data, compared the whiz wheel with my Ballistics app, both said 41.5 minutes of elevation, but I really needed 44 minutes.
Well, This bothered me. I switched back to my 308 and shot. I found things on the berm to shoot. Lazed them, looked at the chart, dialed the elevation, boom and hit. This was true data here. The 308 data was on. 250, 254, 500, 508, 745, 750, 755, 1000, 1008. Everything I aimed at I could hit with the 308. good numbers.
Ok go back to the Grendel and try to refine it as I did the 308. 250, 500 good... Wait was That a little low? Yes. So I ran everything all over again. I ran a box test on my scope. Good data there. tracks a little off at the high end but not bad and I can account for it. (Vortex PST)
So then I Shot at all distances I could. Took note of the elevation that It actually took to be zeroed at that distance, and compared to the numbers I already had. Well It was different. Close, but different.
I then set my chrono back up at 200 yards. Same number.
So I start to play with the BC of the bullet. I ran it down.... Way down.... And got the numbers on paper to match what I was really seeing. I kept the 200 yard velocity the same, lowered the BC, and raised the muzzle velocity.
Now I did all of this at a 3000 DA, so I am curious to see if it changes with the atmosphere, but It is exactly true right now. It is so true that, believe it or not, I couldn't miss with elevation. Wind was light, but enough to push 1-2 minutes, but elevation was perfect.