Ballistic Coefficient of a 139gr. Scenar

[Exhaust3]

I've searched the archives of the boards and cannot find consistent information regarding the BC of the Lapua 139gr. Scenar. I've read it's anywhere from .548-.569. Any information or website would be helpful. Thanks for your input.

 

[memilanuk]

IIRC, the listed B.C. in Sinclair Int'l catalog is 0.615. SMK 142 is given as 0.595, JLK, Cauterricio, & Clinch River 140gr VLD's given in the 0.625-0.630 range.

Actual results may vary depending on the conditions under which you launch them... that and a G1 BC isn't a very good fit for long spiky bullets like these.

HTH,

Monte

 

[BR]

i set my drop charts using a g1 function of .615 it has been right on out to 1680yds

 

[dantec]

G1 is link to a grave table the G1 closely all major use G1 to give a BC value that allow to compare product and some time make easy adds to sale bullets

If you want a true BC value best is to on JBM website and use the online software to compute a true BC with two know velocity at two set distances

example : muzzle and 200 yards

and select the right G table, G table are link with bullet form from flat base to boat tail with secnat ogive ...)

note BC value is link with trag curve nad drag curve vary, not a straight horizontalline ) so BC vary with velocity that when you check Sierra Web site you get three BC value for one bullet

BC of lapua is a bit optimitic or perhaps check under unknow weather conditions becuase barometric change change air density and air density change Mach velocity


another more quick and no pain

you load two bullet diffrent brand at SAME velocity example

142 SMK and 139 Scenar you make two zero at 100 yards and you check how much elevation you need to reach your traget at 1000 yards, lower is the value in elavtion request highter you BC bullet
good shooting

DAN TEC

 

[rhino]

139 and 142 SMK are pretty much the same on dope to 1k. This out of a 1-8 twist 28 inch Pacnor 3-groove barrel.

139 groups better up close and does great at 1k. 142 doesn't seem to want to group good up close, but seems to be similar at 1k.

Sounds odd I know! But that is what I have seen first hand in my rifle...which I no longer have.

RHINOUT!