Is there anyone who has estimated BC at varied velocities for the 139gr Lapua Scenar in cal 6,5 mm. I tried asking Lapua, but they had estimated it at 800m/s only.
I know that this is a long shot, but there are many people using this forum...

I don't know about the Balistic Co-efficient, but I know it's one terrific bullet. All the Scenars in 6.5 are. I use these Lapuas in 108, 123 and 139 as well in my Remington Classic. It's not uncommon to get .5 groups (5 shots/100yds). I load the two lighter ones with VihtaVouri 550, and the heavier bullet with VV560. The two companies, Lapua and VihtaVouri are related. You'll find VV powder heavily used by benchrest shooters. Best wishes.

Cal - Montreal

So you use N550/560. What caliber do you use? Does it perform better, precision-wise with the Vihtavuori 500-series than the 100-series, or is the higher velocity the only reason for your choice?

I've heard stories saying that the 100-series is a better choice if you are looking for tight groups.

[ 05-01-2003, 15:49: Message edited by: Olimahtes ]

Olimahtes,

The BC of the 139 grain is listed as .615 in the Sinclair International catalog.

I shoot these at 2700 fps MV, and the come-ups are as predicted using BC = .615 in the "Point Blank" ballistic program, so I think it is a pretty good number to use.

I load 260 Rem with H4831SC powder, barrel is 1 in 8 twist Shilen.

Good shooting!

Bill

I know that there is only small differences, but still. I load my 139 gr Scenar to MV 2840 fps or 865 m/s (6,5x55). At 300 m the velocity has dropped to 2090 fps or 640 m/s (according to modelled data) and by then it seems unlikely that the BC would remain the same.

In fact, after comparing the position of my groups at 300 m (a looot of grops) with modelled data, I can see that there is a slight difference.

[ 05-02-2003, 22:09: Message edited by: Olimahtes ]