ok I been using strelok and my numbers are off.. when I put data in to make 1000 yrd dead on my 600 is low.(close). messed and messed with it and was told to use applied ballistics. So i have the app. now and am having trouble.. would someone walk me threw it.. give me their data used .. here is what I am shooting 42 gn H4350 lapua brass 140 gn hybrid (618 bc) In strelok to get it close I have to use 2750 fps and a bc of 550 .. Its a 24 in barrel 1/10 twist .. shooting 1000 ft elevation in ohio in summer 1.75 scope height.. I dont know powder temp .. divination,,, and so on.. im at 32,25 moa at 1000 and 13 moa at 600 ..17 moa at 700 .. I have shot an advance LR sniper course and have had some high scores.. but have to use to sets of data.. one to 600 and one from 700 to 1200
Yeah, I have to agree with the guys - trying to second guess things like this is what makes me think of the old line "Garbage in, garbage out" (all respect here, but just saying you'll beat yourself to death with this approach. You need to find out why your input data is wrong - don't try to manipulate the data you DO have right to make the results fit).
140 gn? So you are using a .260 of some colour? Is that ok with 1:10 twist (I only have a 6.5x55 with 7.8" twist, just asking the question)
Take the BC (G7 = .317) and use it as a G7 value in the app - don't even consider changing it unless you know what you are doing - and then don't
Find the velocity with a DECENT chrono and use it - ok, you can play with this a VERY LITTLE BIT if it's very HOT or COLD.
Until you're close forget the temp dependency for velocity for a while (within reason).
But the other parameters are all quite important:
Like scope height.
Actual click values on the scope rather than the nominal ones.
Real ranges, including inclination/declination.
Zero (make it 100 yards/meters to reduce atmospheric issues)
G1 (.618) v G7 (.317) values and use it with the correct drag curve.
Atmosphere (esp the old station pressure v corrected), and
UNITS!!!! Make sure they are correct
(I screwed up here once, which I will explain to show you how easy it can be to go wrong)
I had gotten a new MOA scope and had the AB set to 1/8 MOA clicks. I knew the scope was 1/8 MOA clicks, but the markings around the turret were MOA (1, 2, 3, 4 ...).
In the heat of the moment I started to use the values on the turret as 10's of clicks rather than MOA (which is 8's of clicks) (I had gotten used to MIL scopes).
So, when AB said 120 clicks (when I should have put in 120/8=15 MOA) I was putting 12 (as 12 x 10) on the scope instead of 15.
Sounds a very basic mistake (it is!!), but it took me a while to figure out where I was going wrong.
I now use MOA in AB for that scope, not 1/8 MOA clicks and interpolate (if it says 12.5 MOA, I put in 12 + 4 clicks)
I still cannot believe I was that stupid.
So - double/triple check everything.
Cheers, Farmer