Comparing chrono data to results on target

[Wildstreak]

And just like that my concerns about SD and ES are gone. Thanks.

 

[Wildstreak]

If your cold bore shot is accurate, you'll only need one. Don't go down that rabbit hole of trying to make your hunting rifle shoot like a precision target rifle.

This is something I need to be more comfortable with instead of constantly diving headfirst into a bottomless rabbit hole.

 

[Eric H]

This is something I need to be more comfortable with instead of constantly diving headfirst into a bottomless rabbit hole.

If you get <1 MOA @ 100yds, that's a good hunting load.

 

[Mikecr]

If you get >1 MOA @ 100yds, that's a good hunting load.

Yeah, if you hunt barn broadsides at point blank range

 

[std7mag]

The ES/SD on a 3 shot string is not enough to go on.
SD especially, you want 10-20 rounds to make it more meaningful.
Something as simple as the way you prep your brass, to a switch of primers can effect your ES/SD.

But the target doesn't lie. Your most accurate on the target is the most accurate on target.

Personally, if your going to be shooting longer ranges, even with the data you have, I wouldn't be happy with.

I'm looking for ES in the low teens or lower, SD in single digits.

You might want to set a target out at 600-800 yards and see what happens on the paper there.

 

[std7mag]

Yeah, if you hunt barn broadsides at point blank range

I think he meant <...
But, yeah.

 

[Wildstreak]

The ES/SD on a 3 shot string is not enough to go on.
SD especially, you want 10-20 rounds to make it more meaningful.
Something as simple as the way you prep your brass, to a switch of primers can effect your ES/SD.

But the target doesn't lie. Your most accurate on the target is the most accurate on target.

Personally, if your going to be shooting longer ranges, even with the data you have, I wouldn't be happy with.

I'm looking for ES in the low teens or lower, SD in single digits.

You might want to set a target out at 600-800 yards and see what happens on the paper there.

I had shot strings for each rifle that were single digit ES/SD. They just didn’t produce the best results on paper. But like you said, the sample size was small.

 

[Rick Richard]

I had shot strings for each rifle that were single digit ES/SD. They just didn’t produce the best results on paper. But like you said, the sample size was small.

We know Your sample size was small, but in my experience it is a good indicator how all the others will be. So if that is what you have then work on reducing it….if need be.

 

[FireFlyFishing]

I had shot strings for each rifle that were single digit ES/SD. They just didn’t produce the best results on paper. But like you said, the sample size was small.

If that’s the case, you may keep the same powder charge and mess with seating depth. Potentially, you’ll get the good numbers and good groups down range.

 

[Varmint Hunter]

Test the loads at 500yds and you will know exactly how the SD is (or isn't) affecting the group size at your maximum hunting distance.

 

[Eric H]

Yeah, if you hunt barn broadsides at point blank range

Well, that works all the way to 300yds.

 

[FEENIX]

This is the 6.5 shot at 200. ES was 22 and SD was 12.6

This is the 280. I was not happy with any of the groups out of that rifle. SD was 13.25 and ES was 26.5

Interesting though, that particular powder charge had shot pretty well previously, I had a couple half MOA groups at 300 with that powder charge.

The group pictured was shot with virgin brass though it had been sized and processed. Possible that had something to do with it. Don’t know.

Most of us will try to tighten the groups before trying further out. Good luck!

 

[FEENIX]

This is the 6.5 shot at 200. ES was 22 and SD was 12.6View attachment 580922

This is the 280. I was not happy with any of the groups out of that rifle. SD was 13.25 and ES was 26.5

Interesting though, that particular powder charge had shot pretty well previously, I had a couple half MOA groups at 300 with that powder charge.

The group pictured was shot with virgin brass though it had been sized and processed. Possible that had something to do with it. Don’t know.View attachment 580923

Most of us will try to tighten the groups before trying further out. Good luck!

 

[Doom2]

Typically a velocity deviation of 100 fps is only going to show up as 1" or less (0.5 MOA) at 200 yds (for a slow 168 gr 308 in this case) so trying to correlate POI with velocity from the normal noise is not easy and will probably not be possible. Depending on barrel harmonics you may actually find that the faster rounds impact lower.

Keep this in mind. The velocity data you obtain has absolutely no knowledge of where the barrel is pointing when the bullet is released. On the other hand, when you shoot groups at 100yds your barrel harmonics (and shooter) determine group size. Velocity and BC have no measurable effect on grouping.

EDIT: Small groups at 100yds are the result of minimizing the rate of change in barrel deflection at the point the bullet exits the barrel. It is a function of bullet velocity but only as it relates to barrel time.