Truing Dope Question

[spennebake]

I have some confusion with truing my dope and looking for some suggestions on what I am missing.

I am running 109 hybrids. When using a G7 of .299, I can stack up rounds on the water line at 988 yds. When I come in to 732 yards I am 5" high. My zero is confirmed and is half a tenth high at 100. I have double checked all my input data but obviously I am missing something. Gun is shooting good as you can see in the 1k group below.

 

[KnowNothing256]

How sure are you of the yardage at 732? Just throwing some SWAGs into Hornady’s G7 calculator at sea level or so, 3000 fps MV, if that plate was actually at 720 yds with a 732-yd DOPE you’d see impacts 5” high. Pretty much same story at 2900 FPS.

 

[hafejd30]

I’ve had better luck using the G1 bc when tuning

Sight in at 100 then I shoot multiple distances to establish the drop.

If you enter your MV, temp, humidity, BP etc you can establish a drop chart to get you close

After you shoot you can adjust your bc numbers to tune the ballistic data into your actual drop.

Make sure your scope to bore height is correct as well. If your scope center is 2” above your bore center than make sure that’s correct in your ballistic app

 

[spennebake]

Distance to targets is solid as they have been up for a couple years. We have 62 plates up that we have never questioned Distance as our dope has always lined up.The 988 target was confirmed yesterday. I am in the process of learning this new cartridge, 6 GT. I have double checked all my input data. Today, all shots were ran across a chrono. 45 shots, SD 5.4. The odd thing I noticed last weekend when playing with BC was that I set it at .340 and was center punching 1 & 2 MOA targets from 250 to 750. I new something was odd but didn't care at the time.

 

[1moaoff]

True velocity out to 600 then bc beyond that

 

[Dunraven]

True velocity out to 600 then bc beyond that

OK. So, true mv in the kestrel at 600, then revert to altering bc at, say 1000? Should the kestrel solutions be accurate at all distances then?

 

[1moaoff]

Should be close

 

[Lowlight]

Exactly as noted,

Align the computer using MV at 600 yards,

Then adjust / fine tune the computer at 800 or 1000 (both are fine) using the BC, start off changing the middle number, its a bit of trial and error with the BC vs MV

MV it's 25fps per .1 mil

 

[John Glidewell]

Scope height correct? Tall target test? I had a scope with a tracking issue. Once the tracking error was accounted for in computer it was right on the money.

 

[Dunraven]

Exactly as noted,

Align the computer using MV at 600 yards,

Then adjust / fine tune the computer at 800 or 1000 (both are fine) using the BC, start off changing the middle number, its a bit of trial and error with the BC vs MV

MV it's 25fps per .1 mil

oh that helps. thanks.