1000 yard drop chart

[archer300]

Let's start off and say I am relatively green at the ballistic software.
Kash and I went to a 1000 yard range. I took my tube gun, 6mm xc, 105 Berger hunting vld bullets at 2840 from a 28" barrel. Bc-g1=532, g7=272 according to Berger.
I plug in the numbers and it gives me 8.7 mils of drop to 1000. I corrected my poi and I am only getting 7.9 mils with my scope.
Vortex razor gen 2 4.5-27.
When I use a g1=650 or a g7=327 everything falls in line.
Velocity seems to be in the ballpark, but it was the range graph not a know chronograph.
Any thoughts why the software shows more drop?

Software used is the ballistic ae, and bergers website software

[edge]

Berger is pretty good on their BC's especially since they went to the G7.
I think Bryan Litz has verified the BC's at least to 300 with multiple chronographs and perhaps Doppler.

If your zero was 100 then that is probably too short unless you shoot in the 1's
If you have a good group at 1k then try zeroing that group and dial back to 100 and see where you hit.

Atmospheric conditions not elevation but inches of Hg, wind in your face or at your back?
Scope Height above centerline of bore?

edge.

[archer300]

Right, not sure on the scope height, it's a on a 20 moa rail mounted to a chassis. That's is a good point. Wind as 8-10 o'clock 10-12 mph.
Between sml and shooting long range I am a little distracted and over look some basic principles.
I will take some measurement and recalculate.
Lane

[7mmfreak]

If you didn't use a chrono (and even if you did since they are not always spot on) use the Litz BC (they are accurate to 1% and true your MV.

[7mmfreak]

Another thing I thought of while I was mowing the yard this evening is that if you haven't done a tall target test to verify your turrets' accuracy you will not get good data either. I had that happen recently with a gun at work. By the time I had dialed on 22MOA the optic was off by 2MOA. I've seen it happen with other optics too (Leupold Mk6) where by the time you get to 15MRAD it was off my .5MRAD

[archer300]

Good point! I never check my turrets for accuracy.