Anyone proficient at reading a OCW target?

[GNCC407]

I am changing the bullet and powder combination in my 6x47. I mainly shoot PRS and I have used the Satterlee method in the past with good results. I figure I would see if the OCW test is telling me the same thing. I had a velocity node at 41g and 42g the OCW i did was 100 yards. Am I still looking at a 41.2g and 42.4g OCW? The poi is close between the groups and I know I shouldn't get hung up over group size. Where does one think I should load to go out to 600 yards to test?

 

[Jordanwickham]

I am changing the bullet and powder combination in my 6x47. I mainly shoot PRS and I have used the Satterlee method in the past with good results. I figure I would see if the OCW test is telling me the same thing. I had a velocity node at 41.2-42.4 the OCW i did was 100 yards. Am I still looking at a 41-41.4 window? The poi is close between the groups and I know I shouldn't get hung up over group size. Where does one think I should load to go out to 600 yards to test?

I think you are correct. 41-41.4 have pretty much no POI shift. I find it odd that 41.6 velocity went back down to the 41.2 speeds? This was shot in a round robin correct? The one you marked pull, did you catch a bad breath or your run of the mill pull?
This was shot using a LabRadar or other off the barrel Chrono?
I'd load 41.2 and seating depth test.

 

[stello1001]

I would have done a MV/pressure test first just to see where I pressure out and not to exceed that. I would have then done my OCW without testing for MV.

Anyhow, you want to look for POI changes/consistencies and not group sizes. Where your bullets are hitting laterally.

There's really not much I can see from you test. Maybe try adding more charge weights to the test to see if there are any very clear nodes. You can also stretch to 200 yards and try it that way.

I'm no expert though, hopefully someone with more experience can correct me if I'm wrong.

 

[GNCC407]

I think you are correct. 41-41.4 have pretty much no POI shift. I find it odd that 41.6 velocity went back down to the 41.2 speeds? This was shot in a round robin correct? The one you marked pull, did you catch a bad breath or your run of the mill pull?
This was shot using a LabRadar or other off the barrel Chrono?
I'd load 41.2 and seating depth test.

Round Robin, the pull was a bad breathing shot. Magnetospeed off the barrel.

 

[GNCC407]

I would have done a MV/pressure test first just to see where I pressure out and not to exceed that. I would have then done my OCW without testing for MV.

Anyhow, you want to look for POI changes/consistencies and not group sizes. Where your bullets are hitting laterally.

There's really not much I can see from you test. Maybe try adding more charge weights to the test to see if there are any very clear nodes. You can also stretch to 200 yards and try it that way.

I'm no expert though, hopefully someone with more experience can correct me if I'm wrong.

I did a velocity ladder went up to 42.8 with no pressure, but speed exceeds my comfort level.

 

[stello1001]

You probably don't want to hear this but...

You should try the test again without the magnetospeed as there is always a chance it will throw off your results.

 

[GNCC407]

You probably don't want to hear this but...

You should try the test again without the magnetospeed as there is always a chance it will throw off your results.

I agree, but I haven't had a poi change with the magnetospeed mounted on my spigot adapter off the barrel.

 

[Jordanwickham]

I would have done a MV/pressure test first just to see where I pressure out and not to exceed that. I would have then done my OCW without testing for MV.

Anyhow, you want to look for POI changes/consistencies and not group sizes. Where your bullets are hitting laterally.

There's really not much I can see from you test. Maybe try adding more charge weights to the test to see if there are any very clear nodes. You can also stretch to 200 yards and try it that way.

I'm no expert though, hopefully someone with more experience can correct me if I'm wrong.

I assumed that since he said he only changed the powder and bullet that he had a sense of where his MV / pressure should be based on prior load. If it was a new barrel then yeah all new start based on the pressure.
In OCW you triangulate the center of group and compare that to other groups. As the OP and Stello mentioned group size doesn't mean shit in OCW you can always seat that out if you are in the right node.
Stello is correct that when doing an OCW velocity really inst important information. Nice to know but not a Crux of the testing. But it seems like you have a pretty good grasp on what you are doing. New reloaders get all fucked up trying to look at too many data points at one time.
OCW differs from Saterlee in that Saterlee you are concentrating on velocity and groups as a last step, OCW is POI, then groups, then velocity info for dope. Generally you end at the same point. As you can see by your velocity info and the OCW info being identically good.

I agree, but I haven't had a poi change with the magnetospeed mounted on my spigot adapter off the barrel.

You should be fine with that as long as it's hanging off a handguard and in no way interfering with your barrel.

 

[GNCC407]

I assumed that since he said he only changed the powder and bullet that he had a sense of where his MV / pressure should be based on prior load. If it was a new barrel then yeah all new start based on the pressure.
In OCW you triangulate the center of group and compare that to other groups. As the OP and Stello mentioned group size doesn't mean shit in OCW you can always seat that out if you are in the right node.
Stello is correct that when doing an OCW velocity really inst important information. Nice to know but not a Crux of the testing. But it seems like you have a pretty good grasp on what you are doing. New reloaders get all fucked up trying to look at too many data points at one time.
OCW differs from Saterlee in that Saterlee you are concentrating on velocity and groups as a last step, OCW is POI, then groups, then velocity info for dope. Generally you end at the same point. As you can see by your velocity info and the OCW info being identically good.

You should be fine with that as long as it's hanging off a handguard and in no way interfering with your barrel.

So if I am correct on Newberrys thinking 41.6g would be the scatter and another possible node around 42.2g mark?

 

[stello1001]

@Jordanwickham
Wouldn't the new powder he's trying mean he would still have to test for pressure regardless of it being the same barrel?

 

[GNCC407]

@Jordanwickham
Wouldn't the new powder he's trying mean he would still have to test for pressure regardless of it being the same barrel?

Velocity ladder was done before hand.

 

[stello1001]

Velocity ladder was done before hand.

Yeah, I got that from your previous reply but was just curious why he said it was not as relevant being that the barrel was still the same.

If I had to really pick anything out of that test, it looks like your first two charges might be the better way to go.

 

[Jordanwickham]

Yeah, I got that from your previous reply but was just curious why he said it was not as relevant being that the barrel was still the same.

If I had to really pick anything out of that test, it looks like your first two charges might be the better way to go.

Velocity and pressure are fairly tied. As long as he wasn't on the gnats ass of pressure before then being in the same velocity shouldn't produce odd pressures. Obviously things can go haywire. But it looks like he worked up.

So if I am correct on Newberrys thinking 41.6g would be the scatter and another possible node around 42.2g mark?

Did you shoot 41.8 in this test? It's hard to say for certain since it's a small range of charges. If I were shooting this OCW I would have covered a ~2 grain spread. It really makes things easier to see. 41.8 could be your scatter. But 41 could be your OCW.
Based on this test (the info provided) I'd say 41.2 is your OCW, 41.8 would be your scatter, and 42.4 would be your high OCW.
Might be worth a go to run it from 40.6-40.8 up to 42.8.
But even with this limited OCW your high node is either 42.2 or 42.4

 

[stello1001]

Velocity and pressure are fairly tied. As long as he wasn't on the gnats ass of pressure before then being in the same velocity shouldn't produce odd pressures. Obviously things can go haywire. But it looks like he worked up.

I'm not trying and I don't mean to argue, but i will disagree with this. OP switched powders. Different powders have different burn rates. I can have a load with a 140 hybrid using varget or h4350 that pressures out at ~2700 FPS. If I switch powders to say R16 or R26, i will have that same bullet way way faster before I get any pressure.

OP, would you mind sharing what bullet and powder you are using? Knowing your components does not change how to read an OCW, but sometimes it helps to know.

 

[GNCC407]

105 Hybrid H4831sc

 

[Jordanwickham]

I'm not trying and I don't mean to argue, but i will disagree with this. OP switched powders. Different powders have different burn rates. I can have a load with a 140 hybrid using varget or h4350 that pressures out at ~2700 FPS. If I switch powders to say R16 or R26, i will have that same bullet way way faster before I get any pressure.

OP, would you mind sharing what bullet and powder you are using? Knowing your components does not change how to read an OCW, but sometimes it helps to know.

You are correct. I assumed he was going to a similar burn rate powder ( because of availability ) which I should not have assumed.

 

[GNCC407]

H4831sc work better than 4350 in my rig.