Rifle Scopes Is my new +$2700 scope not tracking properly?

[cgbills]

Ok I have had my new AI AE MKIII in 6.5 Creedmoor with 26in barrel out to the range twice. The first time wearing my old Vortex PST 4-16x50, and the second time with my new Kahles 624i. Both times I was shooting factory Hornady creedmoor ammo, same lot #. Also both times were at the same shooting range, just a little above sea level. The first time I went out with the Vortex I zeroed at 100m and stepped out to 550m. The temperature was a little north of 40 and my muzzle velocity was 2740. It took me about 3.9 mils to get to 550m. I then got my new Kahles mounted, zeroed at 100m and stepped out to 550m. The temperature was 78, but I could not collect MV because my friend had my chronograph. In 78 degrees I dialed my scope to 2.9 mils to get to 550. At first I thought the drastic decrease in dialed mils was due to temperature. After playing around a bit with my ballistics calculator I found that to get 2.9 mils at 550, my bullet would need to be going an excess of 3000 fps in 78 degree weather. There is no way 30 degree change in temperature would cause that kind of spike. Even under relatively sustained fire and a hot bore, I don't think velocity would spike that much. I did a tall target test on my Vortex before and it was right on. I was not able to do a tall target test with the Kahles because of time constraints. What do you all think, does it sound like the scope is not tracking correctly?

 

[JLR]

Sounds like you definitely should do a tracking test to me. Lots of quick/easy ways to check your tracking and verify/eliminate your questions.

Sent from my DROID RAZR using Tapatalk

 

[cgbills]

I will be going back out in a week and will do a tall target and box test. I just wanted to see if my line of thinking and rational made sense.

 

[agbm]

I know you probably have it set, but are you at zero parallax?

 

[BCP]

That kind of tracking should be easy to spot even at 100. You are talking a 25-30% difference so a couple mils will be 9+ inches at 100.

 

[FLIGHT762]

Your elevation discrepancy is exactly 1 MIL off. Is there any way you may have made a 1MIL error in your adjustment when you either reset your turret after zeroing at 100M?

I know I've made mistakes in dialing the wrong direction and other mistakes and then stopping for a minute, then realize the error. It just seems a little too coincidental your error is exactly 1MIL off. Go back, re zero @ 100 M and try it again?

 

[earthquake]

Shooting that same ammo in my Creed, I'm at 3.0 mils at 600 yards. FWIW.

 

[CSTactical]

I shoot factory 6.5 Creed and it is 3.0 to 3.1 for 550mm with Alt 200ft.

Mike @ CSTACTICAL

 

[steve123]

I know a guy here in AZ that had the same scope. It wasn't tracking right and seemed to have POI shifts. He sent it back and that's all I'll say.

 

[bttbbob]

Don't guess, do a 100 yard box drill on a 100 yard sight in target.....Shoot one center mass, come up 8 moa and right 8 moa, shoot, come down 16 moa, shoot , come left 16 moa shoot , come up 16 moa shoot , come right and down 8 moa shoot.....if it doesn't come back center of target, you have a tracking problem. Your outliers should be a perfect box with your adjustments bringing you exactly back to zero.

 

[Rob01]

Elevation should be checked atleast 40 MOA. Small amounts of MOA won't be enough to see a problem.

 

[flatland1]

Both Shooter & Applied Ballistics call for a 600yd come-up of 3.5mils for my 260 Imp 30* with either Lapua or Sierra 123s @ 2870fps; 2400'MSL is the elevation on my range. However, after multiple sessions of confirming a 100yd zero while shooting over the chrono, then moving back to 600, the groups were always 5"-5.5" high with the 3.5 mil come-up. I finally shot a 'tall target' at 100yds and found the value of the clicks on my ERS is .41" instead of .34". I was going to send the scope back, but it's pretty simple to dink around with a zero correction factor in the software and just keep shooting with it.

BTW - I received a Kahles K624i AMR a week or so ago, mounted it with a DTA 20 MOA sloped base on my SRS, and it jives pretty much perfectly with the ballistics apps' come-ups out to 600. We've had 35-45mph winds all but one day since the scope arrived, so I haven't had the chance to shoot a tall target with it, nor to take it back to 1000yds yet.