Help with OCW test

[Berry228]

Today I went to the range and performed an OCW test with my .338 Edge using H1000, 300gr Berger OTMs, Bertram brass. Here are my results:

Velocities:
Group 1- 2710,2749,2743,2735
Group 2- 2747,2758,2730,2727
Group 3- 2761,2757,2795,2788
Group 4- 2769,2833,2780,2805
Group 5- 2820,2797,2813,2784
Group 6- 2800,2769,2787,2786

These groups are confusing me because of the velocity spread. Can someone please help me and tell me where I should load, or should I do another test? I've also posted a picture of the target labeled 1-6. The center is foulers.

 

[BountyHunter]

Did you use a magnum primer?

Your MV is all over the map.

What distance?

 

[ShtrRdy]

What were the charge weights for each load?

 

[Berry228]

I am using CCI 250s and the powder weights are 89.3, 89.8, 90.4, 90.9, 91.4, 92.0. The bullets were just kissing the lands.

The OCW was done at 100yds and the Chrony was set at a distance of 15ft from the muzzle

 

[doverpack12]

I like groups 2 and 5 but either your chrono is inducing some error or the rifle doesn't like that combo with velocity jumping around. I would load more of 2 and 5 and shoot a further distance now and try to get velocities again maybe with the chrono 20 feet out with that big blast.

 

[Gord0]

I was reading another post on here a little while back with some erratic chrony numbers. He had to move it out to 20' as the muzzle blast was messing with it at 15'

 

[trueblue]

I would take group 5 and shoot at 300 yards for groups. Back off the lands about .010,
and see what you get. Play with your seating depth at that point.
If you are not getting any pressure signs, you might ease your way up to 93gr, but most every Edge I have had or seen does very well at 92 gr of H1000.

 

[FURMAN]

Before you move on with load development I would shoot one of those loads again with the chrono farther away. If you get the same results try different primers. Even if the groups looked better the velocity es is horrible and not suitable for long range.

 

[brentc]

For the OCW, I see your near an accuracy node at #2 and a scatter node at #4. This is also indicated by the velocity spreads at the corresponding charges. I'm betting your load will end up within .2 grains of 90 and don't be surprised if that 20 fps ES, reduces down to single digits when you hit the spot.

 

[FURMAN]

He may find accuracy at that powder charge but if those velocities are real it will not hold long distance.

 

[brentc]

He may find accuracy at that powder charge but if those velocities are real it will not hold long distance.

A 20 fps velocity spread isn't bad, but it can be improved. I'm betting it will reduce at 90 grains with a seating depth adjustment.

 

[FURMAN]

The problem is between 89.8 and 90.4 There is 65fps ES. When I run ladders I get in the 10-15fps ES range over .6-.8 grains. Even if he finds an accuracy node there when conditions change everything will fall apart. He can do what he wants but if the velocities are real I would change primers and start over.

 

[dsculley]

Brentc nailed it. With a scatter node at 90.9 gr, you can expect an accuracy node at 90.2/90.3. If pressure is becoming an issue, you can drop back down to the 89.5/89.6 gr range.

FYI, from Dan Newberry's testing, accuracy nodes (or scatter nodes) tend to be 3% charge weight apart. Scatter node to accuracy node then is 1.5%. With the scatter node at 90.9 gr, multiply that by 1.015 and you get 92.26. Or, 90.9 divided by 1.015 gets you 89.55. Depending on pressure, I would test one of these areas.

FWIW

 

[FURMAN]

And that load will still suck at long range if the velocity he is reporting is real.