308 velocity's

[midwesthunter]

Did some load development today for the 308. Not sure but think my chrony might be on crack? Anyways gun needed sighted in. So I used some blackhills match 175 smk that have shot well in past. Well 3 shots later I was zeroed at 100. I shot these three through the chrony and averaged 2680. Then I started with my loads of cfe 223 with 175 smk's loaded to same length as the factory stuff. Started at 46 grains and went to 48 in .5 grain intervals. 47.5 is max. Well all these loads were couple hundred faster then the blackhills. 47.5 and 48 proved best groups. With 47.5 I averaged 3055 fps and 3089 with 47.5. This seams really high to me? Starting load was in upper 2800's. I kept the chrony in the shadows never moved it and was sunny out whole time. Also the cfe 223 has a different smell for sure. Gun is a savage mod 12 bvss 26" tube.

 

[liltank]

Seems high, but the only thing you could do is use the same loads over another chrony and see what happens. Do you have any definitive load data that you have chronographed and proved with drop charts? Prior chrony work?

 

[midwesthunter]

No data I can trust. I'm going to be shooting some loads over varget today. Once I pick a load I like I will do some drops

 

[timmay]

I dont think your chrony is wrong. Ive been reading everywhere that cfe 223 is a good powder and giving higher than normal velocities in 223 and 308

 

[liltank]

If it makes you feel any better, I shot some Alliant Power Pro 2000MR through the chrony today. With a 1:12 twist, 175 Custom Comps shot 2808fps out of a 28" barrel. I was using 47.7 grains of powder. I found a good load at 975yds with a 2.5" dispersion using 48gr. I think I was in the 34MOA realm.