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Posted: 5/13/2012 11:11:55 AM EDT
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Finally got to shoot at 300 yards and extend my 100 yard zero. Dialed in what I thought made sense into Strelok for a 178Amax with 45gr of RL15. It called for 1.5 mils of adjustment. Long story short, no matter how much I changed the data I couldnt get it to match the actual 1.2 mils of correction to group at 300 yards. Tried .530 bc and 2700 fps and it still called for more adjustment than the 1.2 actual.
At 300 does the .3 mil make that much of a difference or are my numbers way off for BC and muzzle velocity? Seems as though I am shooting pretty fast. |
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I can only offer this bit from my experience.
I shoot .223 in a NMA2 for highpower competition. The book says that the comeup from 200 to 300 yds is 2 MOA. I have found that with different shooting conditions the comeup may be between 2 and 3 MOA. It can change because of a lot of variables, but it is always somewhere in the 2.5 MOA (+/- 0.5) area. This is using the same Black Hills 77gr SMK ammo all the time. It sounds like you are talking about using a .308 and a mil-dot scope. I don't know how the changes effect a mil-dot scope based on shooting conditions, but I do know that the guys shooting the .308 in their M14's also adjust like the M16's do. There is a little wiggle room. We are using iron sights for our shooting, so there is no worry about paralax. If the sun comes out it changes the sight picture. If the mirage picks up it changes the sight picture. If you focus on the target instead of your front sight post or scope reticle, it can change your sight picture. The real test will be to take your rifle out under different shooting conditions and see what happens with your group then. As you fill your data book with this type of info you will start to notice trends in what dope to put on your gun if it is overcast, sun from the left, sun from the right, etc. |
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I'm not sure exactly what your question is. I think you're saying that what you're getting in the software isn't matching what the bullet is actually doing. Is that it? Hornady says the BC of the 178 AMax is .495. Something key that ajroyer mentioned was a data book. Check out stormtactical.com. Or just make your own. In the end, where to bullet goes is what matters. DOPE is just an estimate. As you shoot the same load under different conditions, your log book will show you how changes in the environment affected the bullet's trajectory. ETA: Give a look at the LRBC on VortexOptics.com |
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