6BR and Chrono opinions.

[pdhntr]

Well, I think I am making progress after my resizing fiasco.

I am bumping the shoulder only about a .oo1 using the Harrells die, and accuracy has improved.

I ran 12 over the chrono this weekend. It is a new pro chrono digital. Not much I suppose, but a big step up from my old green box.

These are my readings in order:

1. 2783
2. 2766
3. 2789
4. 2795
5. 2789
6. 2789
7. 2789
8. 2789
9. 2783
10. 2777
11. 2789
12. 2795

My questions are:

1. Do you guys shoot some rounds before chronographing to "season" the barrel, or just start with the first one.

2. Do these results look good, not so good, etc.?

Any comments, suggestions or observations would be welcome.

Jim

 

[CoverDog]

You don't say what powder you are using, but your reading are up to 148 fps slower then mine.

 

[pdhntr]

You don't say what powder you are using, but your reading are up to 148 fps slower then mine.

The load is 29.2 gr. Varget, CCI 450 primer, Lapua blue box. Using a .266 bushing.

Jim

 

[CoverDog]

PM sent

 

[pdhntr]

Myself, I shoot 2 or 3 rounds to get the barrel (and chrono) up and going.
Your 2nd shot hurt the ES bad, but the rest look decent to me. Possibly because the barrel wasn't ready/seasoned to fair state.

On a note, I have tested several brands of chronographs, and have found larger spreads with the Pro-chrono then most others.
Sending you a PM of some chrono testing results.

Happy Shooting
Donovan Moran

Thanks so much for the test results.

That pretty much makes my data worthless.

So is there a reasonably priced chrono that can be trusted?

Jim

 

[pdhntr]

I should have studied a little more.

Gees, where have I heard that before.

Thanks.

Jim

 

[CoverDog]

You don't say what powder you are using, but your reading are up to 148 fps slower then mine.

The load is 29.2 gr. Varget, CCI 450 primer, Lapua blue box. Using a .266 bushing.

Jim

Your speeds are probably pretty close for the amount of powder you are using. With your limited info Quick Load says 2789 fps w/29" barrel

 

[pdhntr]

You don't say what powder you are using, but your reading are up to 148 fps slower then mine.

The load is 29.2 gr. Varget, CCI 450 primer, Lapua blue box. Using a .266 bushing.

Jim

Your speeds are probably pretty close for the amount of powder you are using. With your limited info Quick Load says 2789 fps w/29" barrel

Sorry about that CoverDog, I forgot to include the bullet: 105 Berger Hybrid, and yes it is a 29" barrel.

Thanks for running that through Quick Load, and the PM info.

Jim

 

[Exercion]

Extreme spread of 29, SD of 8. I'd say that's pretty good. At least with a standard deviation calculation you are comparing the shots relative to each other, so lets say your chrony is off a bit, over time it should average out and still give useable data. With solid atmospherics and bullet data, you should be able to get a clue whether the chrony is in the ballpark by checking predicted come ups vs actual at distance. Or get a buddy's and shoot over both in series.

Eric

 

[pdhntr]

Extreme spread of 29, SD of 8. I'd say that's pretty good. At least with a standard deviation calculation you are comparing the shots relative to each other, so lets say your chrony is off a bit, over time it should average out and still give useable data. With solid atmospherics and bullet data, you should be able to get a clue whether the chrony is in the ballpark by checking predicted come ups vs actual at distance. Or get a buddy's and shoot over both in series.

Eric

Thanks Eric,

That is exactly what I was thinking of doing. I can shoot out to 575 yds. I don't know if that is enough to get accurate data, but at least I can see what is happening with come ups and vertical in the groups, and try to go from there.

I just haven't shot at that distance yet as I have been trying to correct all my errors to get consistent groups at 100-200 yds, before I stretch the rifles legs.

Even with the very basic equipment I have, I shot 5 groups in a row (this last weekend) that averaged .230 at 100 yds.

Certainly nothing to take on the road, but good enough for the local competition.

Jim