OK 6.8 and precision shooting gurus!!

[shark31]

How closely would the ballistics out of a 16" 6.8 match the BDC of the TA55A? I know that it is supposed to be a close ballistic match to .308, but how close is it? Have you guys running the .308 turrets on your Luepolds and NF optics had much luck with the BDC turrets matching the 6.8 spc? I would like the BDC to be within about 12" at 500 yds. I guess the most important question is how close is it to being on inside of 300yds where I would be doing most of my shooting?

[Stephen_H]

Zak Smith originally posted this on a thread at Lightfighter.net;

The 115gr OTM bullet has a BC of 0.365, and from a 16-18" barrel, should have a MV between 2650 and 2800.

Compare to .308 which has a BC between 0.395 (150gr) and about 0.496 (175gr), and a MV of 2500-2700fps from a 20" semi-auto.

This is also darn close to a 75-77gr 5.56 (BC 0.34 - 0.395) with a MV of 2600-2750fps.


_BC_ _MV_ 0 100 200 300 400 500 600 | YARDS

0.365 2800 > -2.53 1.39 -0.01 -7.97 -23.76 -49.59 -87.26 | > 6.8SPC 18.0"
0.397 2700 > -2.53 1.55 -0.01 -8.44 -24.95 -51.66 -90.18 | > .308 150gr SMK 20"
0.447 2600 > -2.52 1.72 -0.01 -8.88 -25.99 -53.28 -92.08 | > .308 168gr SMK 20"



In summary, if you can stand being within 3/4 MOA out to 600 yards, a 308 reticle will work.