80 gn Berger vs 80gn SMK major velocity differences

[Fotheringill]

Possibly off on a tangent, but-

Same brass was confirmed.

Necks turned exactly the same?
Neck thickness exactly the same?
Neck "tension" exactly the same with a seated round for each?

 

[JimSC]

Possibly off on a tangent, but-

Same brass was confirmed.

Necks turned exactly the same?
Neck thickness exactly the same?
Neck "tension" exactly the same with a seated round for each?

Al I do with cases is deprime, Fl size with Redding S bushing, SS media tumble, anneal and then toss into a bin to be primed when I load. Before priming lengths are checked and I trim chamfer and deburr any that are longer than 2.755 back to 2.750. Only primers I have used for months now are the same lot of Federal 205's

I think the issue has more to do with the light now. I always E to SE shoot before noon which means the sun is low on the horizon and hitting the chrono from behind and slightly to the left. Also could be the fact that chrono may have taken one too many dirt roads in the back of a Jeep for several years. No matter I have been looking for a excuse to buy a Labradar, now I have one

 

[grovey]

If you changed the Bergers seating depth to match the MK's this time around I can't see how you can blame it on the chrono. Repeat the first session if you want to confirm the original differences. Myself... I'd be too cheap to test it again, and just continue with my development.

 

[JimSC]

If you changed the Bergers seating depth to match the MK's this time around I can't see how you can blame it on the chrono. Repeat the first session if you want to confirm the original differences. Myself... I'd be too cheap to test it again, and just continue with my development.

I shot both the Bergers and the SMK's at both .075 off and 0.0 off. The differences in the base to ogive measurements is due to the differences in bullet profile. Seating differences made almost no difference

 

[SWRichmond]

with the possible exception of the Oehler professional models, optical chronographs are a waste of time,

^This