MagnetoSpeed Sporter malfunction?

[MTbackwoods]

Anyone had issues with the Sporter giving accurate velocity with a big boomer? The velocity data for my 7mm was spot on for drops at 730 yesterday. However, my 338 RUM was 1.25 minutes high. When I validate my velocity based on drop, it increases by 104 FPS. I'm running a custom multi bc based on velocity drops from Hornady

 

[shooter7]

No problems with my sporter on either 300 Win Mag or 7mm Rem Mag. I do usually have problems trying to chrono 22lr but that's not a very common thing for me. I typically run with published BCs and JBM Ballistics and can't ever recall being more than about half MOA high or low when I feed it good atmospheric data.

 

[MTbackwoods]

I guess I shouldn't say "custom". It's the published bc from their website but it's the multi bc drag function

 

[MTbackwoods]

Nobody else?