What's my malfunction?

[WeiserBucks]

I've been using the Berger ballistic calculator for years with great success. Now , all over a sudden, my shots are landing 1.5-2 MOA high at longer ranges , 500+ . Same loads , same rifle/scope combinations, same chronograph reading +/- 15 fps for the proven loads . I ran the numbers through the Hornady calculator and it was within .1 MOA of the Berger calculator. What am I missing here? It's got to be something simple but apparently I'm to simple to nail it down .

 

[dok7mm]

Yeah, it's always something little. I'd confirm inputs, stock torque, scope & mount screws, etc., then you can address ammo or other possibilities.

 

[FearNoWind]

I've been using the Berger ballistic calculator for years with great success. Now , all over a sudden, my shots are landing 1.5-2 MOA high at longer ranges , 500+ . Same loads , same rifle/scope combinations, same chronograph reading +/- 15 fps for the proven loads . I ran the numbers through the Hornady calculator and it was within .1 MOA of the Berger calculator. What am I missing here? It's got to be
something simple but apparently I'm to simple to nail it down .

Unclear whether your changes are because of shooting at longer distances than you used to, if there are atmospheric condition changes like wind, temperature, etc. or some other influencing factor. As the temperature rises air density decreases so your shots will show up higher on the target and the results are exponential as distance increases.

 

[WeiserBucks]

Inputs are good, both rifles shoot sub 1/2 MOA at 200 . I have checked the torque on every screw on both rifles. My chronograph has been spot on since I've owned it . Not long ago I was 100% 1st round hits in good conditions out to 800 . Recently I have been 0% hits at 4 and 500 , all shots landing high. I'm stumped.

 

[gohring3006]

No changes to the rifle?
Like scope height?
Verify the scope is tracking as it should. Like when you move it 10 minutes, it moves 10 minutes or mils whichever you use.

 

[WeiserBucks]

I have verified both scopes via a tall target test and both (NF) passed with flying colours. It's gotta be something in the calculation, but I'm confident in the inputs and prior results. If anything has changed on my end , I can't put a finger on it .

 

[Frank in the Laurels]

If you verified it's not the physical parts of the rifle, scopes, loads bullets, powder etc then the only thing left is weather and atmospheric conditions..nothing else could be involved...myself I always blame scopes, no matter how great we and they think they track and perform there's always doubt..

 

[Khavic]

Are you shooting at a range or location you're familiar with and in a setting you've shot before, or are you at a new place? Are you updating elevation and temperature? Is it maybe time to re-barrel?

 

[dfanonymous]

I've been using the Berger ballistic calculator for years with great success. Now , all over a sudden, my shots are landing 1.5-2 MOA high at longer ranges , 500+ . Same loads , same rifle/scope combinations, same chronograph reading +/- 15 fps for the proven loads . I ran the numbers through the Hornady calculator and it was within .1 MOA of the Berger calculator. What am I missing here? It's got to be something simple but apparently I'm to simple to nail it down .

Copper equilibrium is changing. The barrel is building up copper and the muzzle velocity is increasing. Have fun with that.

 

[WeiserBucks]

All shooting is at a private range and i update the inputs each time i go . Not even close to time to rebarrel and the issue exists with clean and fouled bore . Muzzle velocity is not increasing, I record velocity at the beginning and end of my range trips.

 

[Khavic]

It sounds like the bullet you are using might have a higher BC than you have entered on your program. That's the only thing that explains predicted point if impact at zero, consistent velocity, but higher point if impact at distance. Unless you are shooting at a very steep angle and not adding that in, but I doubt that as it sounds like you are pretty familiar with your system.

 

[WeiserBucks]

Ya , I'm at a loss at this point. Everything was working great and now it has gone down hill quickly. The next time out I'm going to try lying to the calculator until I hit at point of aim and see if it helps narrow down the issue. Whatever false input I have to use may point me in the right direction.

 

[Khavic]

What powder, primer, case, projectile and optic are you using? How are you determining ranges?

 

[WeiserBucks]

140 VLD over 57 grains of Retumbo in Lapua brass with CCI BR2s in my LA 6.5x284 NF SHV

215 Hybrid over 76.5 grains of H1000 in Norma brass with CCI 250s in my 300 WM NF ATACR
Measuring range with a Sig 2000 , shouldn't matter at the place I shoot, all targets are known distance.