Range Report 1000-2000yd Range Discrepancy’s

[Davidu]

I’ll be as brief as possible. I can shoot to 1050yds on my farm. My son and I went to Triple C range Wednesday to shoot farther. My son’s 6.5CM with Zeiss v6 5-30 maxed out at 1200 due to lack of travel. He shoots prone/Harris bipod. I shoot off bench/bags. I gave him my Tikka/PVA 7.5 twist in MPA chassis with ATACR 5-25 to shoot farther.
I don’t hand load. I’m in my late 60’s and have enough hobbies. I shoot 140 and 147 ELD Match. Use a Kestral 5700elite. Range distances were true by Leica 2800. All inputs were correct. Environmentals were good as my 6CM hits were pretty close to expected.
6CM @ 1600 yds:
Kestral 63.5 Moa
True 61.75 moa
So my son shot the 6.5 off a bipod. The rifle was zeroed off bench/bags using Hornady 140grELD M chrono Magneto @ 2725 f/s
1100yds. Kestral 36 moa. True 34 moa
1200yds Kestral 42.5. True 40 moa
1300yds. Kestral 49.78
True 46.5 moa
1400yds Kestral 58 moa. True 54.5 moa
I was concerned about the scope not tracking or scope induced cant
I ran a taller tall scope test today and it seems ok.
100yds(tape measure) x .01047 x 56
moa. = 58.63
Actual = 58.75
My question is :
Is it possible to get the above results with those significant differences in expected vs true due to shooting off a bipod when rifle was zeroed off bags??

 

[Davidu]

Due to a lack of a response, I guess I got a bit too mouthy.
Do the long range shooters on this forum believe a 2 moa difference at 1100 yds, a 2.5moa at 1200 yds, a 3.23moa at 1300 yds between expected and trued poi can be explained by bench rest on bag 100 zero vs shooting prone off a bipod?
Thanks

 

[spife7980]

I would say it’s due more to the shooters handling of different positions and influencing the rifles probably more than the fact that it was sitting on something different. And all of that is assuming that the calculator was trued up properly for that rifle bullet and load combo.

 

[sinister]

I concur.

Do either one of you wear glasses/contacts and the other not?

Do both scopes have the same movement per click?

Are both barrels the same length and twist? (Sorry, just noticed the difference between 6mm and 6.5 Creedmoor)

Whether you use a Kestrel or some other software, you are relying on whoever wrote its math and data. Did you match the Kestrel to the day's temperature, humidity, and density altitude? As they say with computers: garbage in - garbage out. You're relying on the base math logarithms.

As a separate aside, your son might be able to reach out further if his scope base has some slope to it.

 

[Davidu]

Thank you all for reply’s. Kestral environmentals were correct as 6CM results were good using same readings. I use Applied Ballistics custom curve for ammo used, not the G7.
I zeroed my 6.5 CM rifle off bags at 100 yds
My son shot this same rifle at 1200-1500yds off a bipod.

 

[Steel head]

What BC did the 6.5 use?
You may want to double check all the inputs.

 

[Davidu]

I’m using the Applied Ballistics custom curve in my Kestral 5700e
The G7 was less accurate to the true poi

 

[Sig Marine]

Several factors come into play, especially when shooting at longer distances. Chronograph error resulting in an erroneous muzzle velocity (they operate within a margin of +/-), scope tracking, BC needs to be trued (BC changes with velocity), target distances must be exact, data inputs, enviromentals, i.e. there are many things that contribute to numbers not lining up perfectly BUT, that is why you verify your elevations on the target and make adjustments based on what it tells you.

Ballistic apps give you theoretical numbers, the target/bullets give you the actual numbers.

 

[Slab74]

I’ll be as brief as possible. I can shoot to 1050yds on my farm. My son and I went to Triple C range Wednesday to shoot farther. My son’s 6.5CM with Zeiss v6 5-30 maxed out at 1200 due to lack of travel. He shoots prone/Harris bipod. I shoot off bench/bags. I gave him my Tikka/PVA 7.5 twist in MPA chassis with ATACR 5-25 to shoot farther.
I don’t hand load. I’m in my late 60’s and have enough hobbies. I shoot 140 and 147 ELD Match. Use a Kestral 5700elite. Range distances were true by Leica 2800. All inputs were correct. Environmentals were good as my 6CM hits were pretty close to expected.
6CM @ 1600 yds:
Kestral 63.5 Moa
True 61.75 moa
So my son shot the 6.5 off a bipod. The rifle was zeroed off bench/bags using Hornady 140grELD M chrono Magneto @ 2725 f/s
1100yds. Kestral 36 moa. True 34 moa
1200yds Kestral 42.5. True 40 moa
1300yds. Kestral 49.78
True 46.5 moa
1400yds Kestral 58 moa. True 54.5 moa
I was concerned about the scope not tracking or scope induced cant
I ran a taller tall scope test today and it seems ok.
100yds(tape measure) x .01047 x 56
moa. = 58.63
Actual = 58.75
My question is :
Is it possible to get the above results with those significant differences in expected vs true due to shooting off a bipod when rifle was zeroed off bags??

My sako a7 .308 shoots 1.5 moa high with the bipod and dead nuts off my front rest and bags. Same groups, just 1.5 moa high. I’m guessing it’s stock flex. I believe it’s a bell and Carlson stock made for sako. The bipod is a Harris-s. My gap PPR does not change poi with the rest or bipod. I have not had a chance to shoot past 200 with either rifle yet, so I don’t know if the shift holds up at longer ranges.