OCW Node Analysis 700 SPS Tac 20" 175gr SMK

[CK_32]

Just care to see your thoughts on my final OCW for my 700.

Distance @ 300 yards

Notes: Tail wind slight left to right picked up during my 4th group.
Temp cranked up from 82F to about 92F during the test.

So I'm not sure if that explains that last wild group of if that's just a wild node.

But I'm thinking 42.2gr is the ticket.

 

[Jordanwickham]

Not much you can do with an OCW at 300 yards

 

[Jordanwickham]

If you glean anything from this it would be that 44 is the OCW not 44.2. You are confusing group size for OCW.

 

[CK_32]

Not sure I'm tracking. Why not?

Initial OCW was done around 100 yards and there seemed to indicate a node around 44.0 and 42.0gr.

This was the final 5 shot grouping of the 44.0 node sequence at distance. IIRC initial single shot OCW is made at 100 yards. Then followed up with node selection groups at 200 to 300 yards to finalize groupings at slightly greater distance to maximize the spread distance of any given node.

 

[CK_32]

If you glean anything from this it would be that 44 is the OCW not 44.2. You are confusing group size for OCW.

Not exactly. Tho the group is smaller. Im looking at POI + Spread. Which is similar but center of the top two.

But I can see and also could agree 44.0 has the center POI of the lot. 42.4 might be the high end of that node. Again why I'm here to get 3rd part opinions.

Not trying to fight you on this. Just understand the why. I still get confused to this day about OWC grouping findings. As soon as I think I start to understand the process. I still seem to confuse results.

 

[Jordanwickham]

Didn't realize you had done a 100 yard. That's not exactly how OCW works but I can see where you were going.
In real OCW you run a 3 shot round robin at 100 yards. Take the POI node and load up a seating depth test. Then just confirm the load at farther range. Generally at farther range you just can test the stability of the OCW charge by loading the OCW charge the charge above and charge below and shoot it at the same target and it should all group.
I don't know if you did any of the second and third step.
I've never heard of running a 100, 200, and 300 yard OCW.

 

[Snuby642]

I dont follow the 44.0 recomedation?

I would have chose the 44.2 and started on depth testing.

 

[CK_32]

Didn't realize you had done a 100 yard. That's not exactly how OCW works but I can see where you were going.
In real OCW you run a 3 shot round robin at 100 yards. Take the POI node and load up a seating depth test. Then just confirm the load at farther range. Generally at farther range you just can test the stability of the OCW charge by loading the OCW charge the charge above and charge below and shoot it at the same target and it should all group.
I don't know if you did any of the second and third step.
I've never heard of running a 100, 200, and 300 yard OCW.

Yea, I already did the initial OCW @ 100 yards. This is my OCW charge by charge groupings at further range for confirmation and finalization.

That being said do you still see the node at 44.0gr?

 

[Jordanwickham]

I dont follow the 44.0 recomedation?

I would have chose the 44.2 and started on depth testing.

44 based solely on this target is the OCW. 43.8 POI is identical and 44.2 is just slightly lower. If you were to load 44.2 and it was either hot out or your scale drifted or dropped in the +/-.1 grain your POI will start to drift off low.
43.8 and 44 POI is nearly exactly the same. 44.2 is just very slightly lower. But 44.4 is a mile low.

 

[Jordanwickham]

Yea, I already did the initial OCW @ 100 yards. This is my OCW charge by charge groupings at further range for confirmation and finalization.

That being said do you still see the node at 44.0gr?

Based solely on this target but I don't know your other targets. And I wouldn't change things up based off a 300 yards target.

 

[Snuby642]

Isn't 44.3 varget a popular node?

 

[CK_32]

Isn't 44.3 varget a popular node?

Normally the node is around 42.0 and 44.0 from what I've found around the net with these particular rifles. Which is essentially exactly what I found with my personal teting as well.

 

[Jordanwickham]

Isn't 44.3 varget a popular node?

Sure in some rifles. I don't see anywhere that says this is Varget. And I don't know anyone that just says I heard that "X" is good on the internet so I'll just load that and sling lead.

 

[Snuby642]

Looks like using range buddy.
If so the other function will add notes on poi distance for you.

 

[Jordanwickham]

You would also be fine to load 44.1 and run a seating depth test to find the optimal seating and just do some confirmation at all distances.
With OCW when you get it dialed in you should be able to load an increment above and below with your OCW and it should all group decent. Like load 2 at increment below, 2 at OCW, 2 at increment above, shoot it at one aim point and have only a very slightly worse group than the tuned OCW load.

 

[Jordanwickham]

That two above and two below would be best at the middle of your .6 gr node.

 

[Jordanwickham]

But without all the targets I wouldn't suggest you to change anything. And it seems like you have it fairly dialed. I would just warn that with how off the 44.2 is from 44.4 you can go haywire in a big way pretty fast getting too close to 44.4.

 

[Snuby642]

I was talking of a load we run with 175 and varget.

It's late and my notes are at my sons house.

Also it was used by a lot of people here on the hide so we included it in testing.

So don't be a bitch.

 

[Jordanwickham]

Was it in this particular rifle? If not then it's a good starting point. It's pretty obvious that 44.3 in this rifle will be a shit load.

Don't be so soft.

 

[Snuby642]

We also have a 20 inch barrel.
And I guessed varget since a very similar load.

 

[Snuby642]

No I think 44.1 - 44.3 will hold after seating depth test.

Probably the wind at 300 scewed things some.

And the 44.3 was a refrance to a popular load that is close, not to imply using it instead of the 44.2

I dont think when we went past that anyting got better as I remember.
Hogden says 45g max

 

[CK_32]

But without all the targets I wouldn't suggest you to change anything. And it seems like you have it fairly dialed. I would just warn that with how off the 44.2 is from 44.4 you can go haywire in a big way pretty fast getting too close to 44.4.

Yea I agree, kind of what I was seeing as well. Again with my OCW and my previous ladder test with this rifle which showed me this node originally.

Ill probably just leave it at 44.0gr to leave room for pour/scale error.

 

[CK_32]

No I think 44.1 - 44.3 will hold after seating depth test.

Probably the wind at 300 scewed things some.

And the 44.3 was a refrance to a popular load that is close, not to imply using it instead of the 44.2

I dont think when we went past that anyting got better as I remember.
Hogden says 45g max

I don’t plan on going any higher than the 44gr range. Beyond that you’re just wasting brass life. I’m sure I could go to around 46gr but I don’t think it would benefit me much and again I’d just be killing my brass.

But you are right I’m using Varget - Win Brass - CCI 200 primers.

 

[Snuby642]

Still have not got to my notes at my sons house but I found a picture or two.

They were labled 42.3 and the other 44.3 the problem being I don't remember which was the 168g and the other 175g.

Mostly my son shoots that 308 and I just load for it.

I may have confused the bullet weight, I apologize.

I load for a variety of guns and calibers for my family and get them mixed up without my notes.

Now to figure out if the 43.2 was 175 as labled or the 168.

In iether case it was a nice group.
I can't get it to transfer from range buddy for some wierd reason.

But hell I did not shoot it my son did.

 

[nn8734]

Not sure I'm tracking. Why not?

Initial OCW was done around 100 yards and there seemed to indicate a node around 44.0 and 42.0gr.

This was the final 5 shot grouping of the 44.0 node sequence at distance. IIRC initial single shot OCW is made at 100 yards. Then followed up with node selection groups at 200 to 300 yards to finalize groupings at slightly greater distance to maximize the spread distance of any given node.

What was your MV/SD/ES at 44.2 and 44.4g?

Those are the two best looking groups...44.6 looks ok but prob lies just outside the node..

 

[Jordanwickham]

Still have not got to my notes at my sons house but I found a picture or two.

They were labled 42.3 and the other 44.3 the problem being I don't remember which was the 168g and the other 175g.

Mostly my son shoots that 308 and I just load for it.

I may have confused the bullet weight, I apologize.

I load for a variety of guns and calibers for my family and get them mixed up without my notes.

Now to figure out if the 43.2 was 175 as labled or the 168.

In iether case it was a nice group.
I can't get it to transfer from range buddy for some wierd reason.

But hell I did not shoot it my son did.View attachment 7390100

I would suspect the 43.2 is for the 175g and 44.3 would be for the 168g.

 

[Jordanwickham]

What was your MV/SD/ES at 44.2 and 44.4g?

Those are the two best looking groups...44.6 looks ok but prob lies just outside the node..

I agree those are the best looking groups... That's not the intent of an OCW test. Notice the POI change between all the groups you see that 3 are pretty identical and 2 are way off. Though 2 that had wildly different POI had good groups loading on the groups would produce terrible results if anything were to change.
OCW finds a powder charge that is resistant to change by finding POI stability over a varied charge weight. You can then tune any charge in that node with seating depth for group size optimization.

 

[nn8734]

I agree those are the best looking groups... That's not the intent of an OCW test. Notice the POI change between all the groups you see that 3 are pretty identical and 2 are way off. Though 2 that had wildly different POI had good groups loading on the groups would produce terrible results if anything were to change.
OCW finds a powder charge that is resistant to change by finding POI stability over a varied charge weight. You can then tune any charge in that node with seating depth for group size optimization.

POI is irrelevant at this stage of TE as the barrel will vibrate slightly differently with different load recipes, resulting in different POI relative to POA for each iteration. Example: You ever see POI shift with and without a can but same ammo?
POA equaling POI is more about accuracy (Measurement of shooter ability, ammo and rifle system) vs precision (Measures Rifle and ammo only).

I would only care about four things at this juncture, one of which is visible in his target pics, the other three which are not. They are:

1) Mean muzzle velocity
2) SD
3) ES
4) Vertical Dispersion*

* I couldn’t care less about horizontal dispersion at 300+ as that is driven by factors that have usually have nothing to do with the ammo itself. I also don’t measure overall group size as it’s largely meaningless if just evaluating load consistently (it is excellent for measuring overall precision potential of shooter and his system (rifle set up and ammo) as eluded to above).

Once I settle on a preliminary load recipe, I’ll go ahead and zero my rifle at 100 for that load then get on at 600. Once on at 600, I fire a test sample of 10 rounds at the 600 yard target, with the goal of keeping all 10 rounds within a six inch (or less) vertical string while maintaining a single digit SD.

If the load holds up, it’s ready to be put into production. Subsequent sessions, I’ll gather and validate my drops from 200 to a grand or whatever max effective range at 100 yard increments.

 

[Snuby642]

I would suspect the 43.2 is for the 175g and 44.3 would be for the 168g.

I believe sir you are probably right at that.
Getting a lot of powder under the 175g was a problem as I remember.

My sons ruger tactical has a problem of a stingy magazine. So everything has to be standard mag lenght.

168g smk's rule in that thing but longer bullets get to crunching powder fast.

We will be trying hybrids to see if we can streatch it's legs farther.

 

[Jordanwickham]

POI is irrelevant at this stage of TE as the barrel will vibrate slightly differently with different load recipes, resulting in different POI relative to POA for each iteration. Example: You ever see POI shift with and without a can but same ammo?
POA equaling POI is more about accuracy (Measurement of shooter ability, ammo and rifle system) vs precision (Measures Rifle and ammo only).

I would only care about four things at this juncture, one of which is visible in his target pics, the other three which are not. They are:

1) Mean muzzle velocity
2) SD
3) ES
4) Vertical Dispersion*

* I couldn’t care less about horizontal dispersion at 300+ as that is driven by factors that have usually have nothing to do with the ammo itself. I also don’t measure overall group size as it’s largely meaningless if just evaluating load consistently (it is excellent for measuring overall precision potential of shooter and his system (rifle set up and ammo) as eluded to above).

Once I settle on a preliminary load recipe, I’ll go ahead and zero my rifle at 100 for that load then get on at 600. Once on at 600, I fire a test sample of 10 rounds at the 600 yard target, with the goal of keeping all 10 rounds within a six inch (or less) vertical string while maintaining a single digit SD.

If the load holds up, it’s ready to be put into production. Subsequent sessions, I’ll gather and validate my drops from 200 to a grand or whatever max effective range at 100 yard increments.

The verticle dispersion between 44.2 and 44.4 is about 2" so based on what you just said it would not be an ideal spot to load.
Not sure why you would load at 44.4 and hope to get a 1 MOA group that is unstable to changes when you could load at 44 and have a .5 MOA group that is stable.

 

[nn8734]

The verticle dispersion between 44.2 and 44.4 is about 2" so based on what you just said it would not be an ideal spot to load.
Not sure why you would load at 44.4 and hope to get a 1 MOA group that is unstable to changes when you could load at 44 and have a .5 MOA group that is stable.

Huh?

Im taking about the vertical dispersion of the five rounds in each individual group. 44.2 and 44.4 appear to have the two tightest vertical dispersion measurements.

He shot those at 300 yards, right? The vertical spread for 44.2 appears to be about 2”, which is .66 MOA at 300. Both his groups at 44.2 and 44.4 are tighter vertically than the 44g group. Are you looking at the pics in the original post?

Also, not sure if by stability you are refering to the POI location itself but to me, the barrel harmonics appear slightly different once you get to 44.4g and the resulting bullet is about 1 MOA low relative to charge weights in the 38.8-44.2 range.

If you’re referring to something else, then disregard the above paragraph (up to you if you want to clarify).

Solely based on the target results, I’d work with the 44.2g charge and swap primers and play with seating depth to see if I could improve upon it (assuming 44.2 gave me single digit SD and a MV I was happy with). If I couldn’t get 44.2 to work consistently, I’d try 44.1 and 44.3. Alternatively he could load 10 rounds each at 44 and 44.2, fire them at two targets over a chrono at 300 and compare the muzzle velocity data and vertical dispersion. Then move forward with developing the better performing load.

Anyway, unless we have chrono data for those loads we cant see the complete picture, the target itself only tells half the story, which is why I asked the OP if he can share that data.

 

[Jordanwickham]

The stability I'm talking about is that from 43.8-42.2 the POI between them is very stable. Whereas 44.4 goes far south. So if you were to load at 44.4 any number of conditions can change whether it be weather, scale drift, scale accuracy, ECT your groups will be all over the place because between 44.2 and 44.4 is a 2" POI shift.

 

[nn8734]

The stability I'm talking about is that from 43.8-42.2 the POI between them is very stable. Whereas 44.4 goes far south. So if you were to load at 44.4 any number of conditions can change whether it be weather, scale drift, scale accuracy, ECT your groups will be all over the place because between 44.2 and 44.4 is a 2" POI shift.

So you are comparing the POI across all the groups, gotcha. I don’t think I recommended 44.4 other then mentioning it had a tight vertical dispersion, but instead recommended 44.2 as that seems to be optimal based on the one 5-round group’s appearance. you get both stability and precision, assuming that test group’s performance is representative of a hypothetical population of rounds with that charge weight. Weather can be accounted for but a drifting scale is harder to detect so it makes sense to load south of 44.4 grains for that reason.

Hopefully he will post the chrono data. Then we will know for sure if 44.2 is in fact worth further developing or perhaps 44 is more optimal, larger vertical spread not withstanding.

 

[CK_32]

So you are comparing the POI across all the groups, gotcha. I don’t think I recommended 44.4 other then mentioning it had a tight vertical dispersion, but instead recommended 44.2 as that seems to be optimal based on the one 5-round group’s appearance. you get both stability and precision, assuming that test group’s performance is representative of a hypothetical population of rounds with that charge weight. Weather can be accounted for but a drifting scale is harder to detect so it makes sense to load south of 44.4 grains for that reason.

Hopefully he will post the chrono data. Then we will know for sure if 44.2 is in fact worth further developing or perhaps 44 is more optimal, larger vertical spread not withstanding.

Wish I could, but I’m not fortunate enough to afford a chrono as of right now. Wish I could but I can’t justify it.