OCW results interpritation

[Monteria]

First of all, hello and thank you for any assistance that may be provided. I've been reading here a while. I registered not too long ago so that I could buy a scope from the classifieds, and now I figure I might use that registration for something constructive.

How do Yall interpret the OCW results below?

Notes* estimated velocities are from QL @ 90°. Actual are @70° from a shooters chrony beta, which I'm hopefull is the reason my SDs look so horrible.

These were fired round robin and two bad shots are marked with a red hash and #1.

 

[Rardoin]

Pick the charge in the middle of #1 and #2 charge weights and do a seating depth test.

 

[The Oregonian]

Pick the charge in the middle of #1 and #2 charge weights and do a seating depth test.

I agree...it is also hard to get much of a statistical sample for velocity from 3 shots. Measure again during seating depth tests with the additional shots at the same charge.

 

[nksmfamjp]

I would use 4 as my center point and run another iteration at 0.2gr increments.

How did you determine your oal?

 

[Monteria]

I'm glad someone likes #4+. I hope more do too. Its hard to explain away that one bad shot though. if I was stuck at the low node I'd probably just start over. I doubt anyone buys a 300 Weatherby to shoot 2850fps, even with 215s...

My plan was to work with .2gr increments from here in hopes of nailing it down before seating depth testing because I dont have much room for adjustment there.

My current OAL is as long as would eject a live round without removing the bolt. On the other end of that, I dont have far before the ogive ends up below the case neck.

IF the Berger 215s dont work out because of these constraints, my options are to find another bullet or sell this to someone who wants to shoot 180s and buy myself another in Win Mag

 

[The Oregonian]

I'm glad someone likes #4+. I hope more do too. Its hard to explain away that one bad shot though. if I was stuck at the low node I'd probably just start over. I doubt anyone buys a 300 Weatherby to shoot 2850fps, even with 215s...

My plan was to work with .2gr increments from here in hopes of nailing it down before seating depth testing because I dont have much room for adjustment there.

My current OAL is as long as would eject a live round without removing the bolt. On the other end of that, I dont have far before the ogive ends up below the case neck.

IF the Berger 215s dont work out because of these constraints, my options are to find another bullet or sell this to someone who wants to shoot 180s and buy myself another in Win Mag

The way I understand OCW, and I may not understand it correctly, is that you don't necessarily look for the smallest group, you look to see where successive groups print relative to POA, but obviously group size plays into it as well. That shows less sensitivity to changes in powder. Then work in smaller increments within that node, and test for depth when that is done. Maybe the final two steps are recommended in reverse order from what I listed, I don't recall.

 

[Monteria]

I'm not looking for the smallest group, I'm looking for the least vertical dispersion. But, I also dont know how to interpret what I'm seeing. Its definitely 1 and 2 or 4 and 5. But which, or does it matter? And what is the deal with #3?

 

[asd9055]

I'm glad someone likes #4+. I hope more do too. Its hard to explain away that one bad shot though. if I was stuck at the low node I'd probably just start over. I doubt anyone buys a 300 Weatherby to shoot 2850fps, even with 215s...

My plan was to work with .2gr increments from here in hopes of nailing it down before seating depth testing because I dont have much room for adjustment there.

My current OAL is as long as would eject a live round without removing the bolt. On the other end of that, I dont have far before the ogive ends up below the case neck.

IF the Berger 215s dont work out because of these constraints, my options are to find another bullet or sell this to someone who wants to shoot 180s and buy myself another in Win Mag

I would use #4 also, do a seating depth before playing with the load. Look at seating the bullet deeper.

 

[338 dude]

Yes 4 is a small group and while that is good there is the least amount of vertical dispersion also in regards to where the group impacted on the bull's-eye it is higher than others telling me the barrel is near the top of the Oscillation before it started down you see other groups are much lower but what do I know

 

[Rardoin]

Like 338 said, look for a 2-3 successive charge weights that have a group center that impacts in the same area relative to the aim point. That will be an area that will be less sensitive to variations in temperature/minor case volume differences/neck tension differences etc. Once you find that zone pick the middle charge and work on seating depth. You will then be very close to an optimal load. Then do a fine charge test in increments of .1-.3gr depending on case capacity. For my 6.5 Creedmoor it was .1gr and my .284 and 7 SS .2gr. You won't be in a proper powder 'node' if the group size takes a dump .2-.3gr on either side of your chosen charge in a case the capacity of a 300 Weatherby.

 

[hunter67wa]

Thats why I would look at 3 at it is between 2 and 4 and if you center the groups 2,3,4 are it.

 

[Korhil78]

I didn't see where you said you had any pressure signs. Did you? If not, do you think you could go to a higher charge test?

 

[Rardoin]

I didn't see where you said you had any pressure signs. Did you? If not, do you think you could go to a higher charge test?

I like to span 1500 or more fps and run the test until I get stiff bolt lift. My ocw tests are usually 10-12 charge weights.

 

[Monteria]

No pressure signs. However, I was shooting at 70° and I used Quickload to forecast pressures at 95°. I hunt from 20° to 100°, so I am trying to make sure my loads are summer safe.

I am aware that, with temperature variations that big, I may have to load to temp eventually. Maybe I should just start now?