OCW results/interpretation?

[Dildobaggins]

Bought a 26in, 6br, 1-8 twist barrel from NSS.
Broke it in/fireformed 100 pieces of brass.

Using Hornady 105 BTHP and varget, with CCI 450 primers.

The first picture is from fireforming and just shooting groups at the cardboard with different charge weights.

The second is from the actual OCW test. I only did 3 shot groups.

Questions:
What powder charge would you go with?

This was done jumping the 105s .020 from the lands. I understand every barrel differs, but could I tighten one up a good deal by playing with seating depth?

Thanks fellas

Fire forming loads

OCW TEST

 

[RegionRat]

Was there any significant wind event when you shot the 29.8 group?

It seemed to really jump to the right compared to the ones next to it on either side.

If you ignore the 29.8 step, the rest are a nice slow steady change which would imply you could just pick your desired speed with impunity and go test seating depth.

I would go re-test the 29.6 to 30 to see if that jump repeats cause if it does you will want to stay the hell away from there.

You may want to check a mild jam to see if these bullets ever cluster, even if you don't ever plan to run it jammed. For the trouble it will show you what if any effect you are getting from your throat dimensions.

 

[Dildobaggins]

Was there any significant wind event when you shot the 29.8 group?

It seemed to really jump to the right compared to the ones next to it on either side.

If you ignore the 29.8 step, the rest are a nice slow steady change which would imply you could just pick your desired speed with impunity and go test seating depth.

I would go re-test the 29.6 to 30 to see if that jump repeats cause if it does you will want to stay the hell away from there.

You may want to check a mild jam to see if these bullets ever cluster, even if you don't ever plan to run it jammed. For the trouble it will show you what if any effect you are getting from your throat dimensions.

I pulled a shot real bad on 29.8. So I re did the 3 shot group, and cut it out of the paper and pasted it next to the rest the best I could that's why it looks out of wack. POI was about the same as the rest.

I'll re test 29.6-30.0 and see which one I like and then move to seating depth.
The gun is a repeater action in a KRG bravo. I have an urban rifleman front bad rider on it. I'm going to get a shadetree top for my bald eagle front rest, and a better trigger. I pretty much single feeding it as it is, so jamming them doesn't bother me! Trying to make a wannabe f class rig, to make sure I like it, before I go down that path

Thanks for the information man!

 

[RegionRat]

Just keep in mind...
The shot group center shift is the whole focus of the OCW test pattern.
You are looking for one of two outcomes.
One is a few powder steps in a row where the group center shift is stable, or if that doesn't happen...
to at least stay away from places where the group center makes big jumps.

Being what we are, it is difficult to try and ignore the actual size and shape of the groups, but the idea is the group center is the priority.
If possible, these are also best shot in a round-robin fashion to mitigate barrel heating and fouling effects.

 

[Dildobaggins]

Just keep in mind...
The shot group center shift is the whole focus of the OCW test pattern.
You are looking for one of two outcomes.
One is a few powder steps in a row where the group center shift is stable, or if that doesn't happen...
to at least stay away from places where the group center makes big jumps.

In hindsight I should have just shot an extra for the 29.8 group and left the group on the paper. Live and learn. Thanks for the info.

 

[nn8734]

Agree w/RR. Reshoot 29.6-30 or maybe even include 30.2. If nothing changes pick the charge that gives you the velocity you want and go to seating depth trials if you don’t like the groups sizes. Otherwise load up 40-60 and start gathering drop data, true your ballistic solver and put the load into production.

 

[Dildobaggins]

Interesting. Not that I disagree with either of you, but I thought 29.4 was a good group. Am I missing something? Will do though. Less monkeying around use of components with 29.6-30, so I won't complain. Haha

 

[nn8734]

Interesting. Not that I disagree with either of you, but I thought 29.4 was a good group. Am I missing something? Will do though. Less monkeying around use of components with 29.6-30, so I won't complain. Haha

OCW doesnt care about group size, its all about seeing center poi alignment (or lack thereof ) and finding poi stability between consecutive charge weights.

 

[spife7980]

I too like the 29.4-29.6 area. I’d do a 29.5 seating depth test because I want to know if I could easily do better or worse.

 

[Dildobaggins]

OCW doesnt care about group size, its all about seeing center poi alignment (or lack thereof ) and finding poi stability between consecutive charge weights.

That's why I post these questions. Still very green to all of this.

 

[waveslayer]

29.5 , seating test and call it a day! Good job

 

[Dildobaggins]

29.5 , seating test and call it a day! Good job

Thanks brother. The 6br was recommended to me from a post on here. Very pleased with it so far.

 

[nn8734]

That's why I post these questions. Still very green to all of this.

All good. Ive been reloading since end of high school 20 years ago and still learning.

What was your muzzle velocity at 29.4-29.6?

And if you’re going to do seating depth, id do one or two test samples at .020 to see if the groups are same at that distance from lands and do another at .040 and .080… reason for the huge gaps is i want to see where the groups start to open so I know the “width” of my “precision node”.

Also don’t shoot traditional groups, shoot dot drills instead. One shot per little 1” pastie. Two rows of three pasties, maybe two separate targets. One for .020 (2 test samples, 3x2 set up) and another at .060 or .080, same set up.

 

[Dildobaggins]

29.5 , seating test and call it a day! Good job

Thanks brother. The 6br was recommended to me from a post on here. Very pleased with it so far.

All good. Ive been reloading since end of high school 20 years ago and still learning.

What was your muzzle velocity at 29.4-29.6?

And if you’re going to do seating depth, id do one or two test samples at .020 to see if the groups are same at that distance from lands and do another at .040 and .080… reason for the huge gaps is i want to see where the groups stsrt to open so I know the “width” of my “precision node”.

Also dont shoot traditional groups, shoot dot drills instead. One shot per little 1” pastie. Two rows of three pasties, maybe two separate targets. One for .020 (2 test samples, 3x2 set up) and another at .060 or .080, same set up.

My muzzle velocity is unknown. I have a magneto speed V3 coming at the end of the week. Feel like I've been shooting in the dark since I started reloading last year.

That was going to be my next question on here. How far to seat them. Good info!

 

[Precision Underground]

Good shooting. I’d go 29.6. You have a big widow there where the impact didn’t
move. The right bias on 29.8 looks shooter induced to me. It looks like right is your tendency. Are you left handed?

 

[Dildobaggins]

Good shooting. I’d go 29.6. You have a big widow there where the impact didn’t
move. The right bias on 29.8 looks shooter induced to me. It looks like right is your tendency. Are you left handed?

Thank you. I used your ELR 3D bag! I am not. The poi is a little to the right, but I did notice that myself, that my groups tended to go from right to left. Definitely need better technique, but my trigger is also set at 16oz which I want lighter.

 

[Precision Underground]

Thank you. I used your ELR 3D bag! I am not. The poi is a little to the right, but I did notice that myself, that my groups tended to go from right to left. Definitely need better technique, but my trigger is also set at 16oz which I want lighter.

It’s a good looking target man you’re doing fine so far. 16 ounces should be plenty light. Keep working at it

 

[Dildobaggins]

here is the original without the cut and paste. Pulled the shot on 29.8

 

[padom]

29.5 and move on.

 

[Devildog]

I agree with everyone one that said 29.5. That’s your sweet spot!

 

[Doom]

You have a nice flat node and probably the in the 29.6 gr range will be a good spot to test at distance. As noted the second 29.8 is a setup bias, which I unfortunately recognize from personal experience.

 

[LR1845]

I'd shoot this again but start at your top and work down...ill bet your upper groups will look better.

 

[Dildobaggins]

I'd shoot this again but start at your top and work down...ill bet your upper groups will look better.

No offense but why would I shoot the whole thing again, when 29.4-30 look like that? I don't understand what it would accomplish?

 

[Precision Underground]

I'd shoot this again but start at your top and work down...ill bet your upper groups will look better.

This is the reason you should shoot OCW tests round robin. 90% of people don’t, but it’s a hugely important part of taking the shooter out of the equation. That being said, whether the OP shot RR or not, the target shows a pattern that makes sense so I’d trust it. I’d guess another node is up around 30.8-31.4

 

[LR1845]

No offense but why would I shoot the whole thing again, when 29.4-30 look like that? I don't understand what it would accomplish?

Sorry I was just going to fix my post....had a dog fight and must of hit post as I went to get that mess stopped.

So I'd reshoot 30.2 down to 29.6 just to verify those upper charges were not shooter error I'd also load up 4-5 of each just in case you pull a shot.
That said I shot out 5-6 BR barrels before I moved to the BRA and the first barrel ended up at 30g varget cci450 and 105 hybrid .070 off the lands.
Second barrel was 30g varget cci450 and seating really didn't matter so the next 3-4 I'd FF 100 pieces of brass at 29.5g then load at 30g and run a seating test.

 

[LR1845]

This is the reason you should shoot OCW tests round robin. 90% of people don’t, but it’s a hugely important part of taking the shooter out of the equation. That being said, whether the OP shot RR or not, the target shows a pattern that makes sense so I’d trust it. I’d guess another node is up around 30.8-31.4

I agree but in most cases the more rounds that are shot the more shooter error comes into play...I personally am not a group shooter and do not know many ppl that can shoot group after group weather its round robin or just groups.

 

[Dildobaggins]

Quick notes. I did shoot round robin. So this is my first 6br, and after researching extensively I was a little worried/odd feeling, but the reason I stopped the test at 30.4 and didn't go any higher was because I was getting very, very slight ejector marks, but a pretty hard/stiff bolt lift at 30.4 and I stopped at 30.6.

I'll go back out and reshoot 29.8-30 because I'm absolutely 100 percent confident that the other groups were not pulled and shot well. If the others group/poi the same, then I'll leave them, and load 29.6

 

[LR1845]

Quick notes. I did shoot round robin. So this is my first 6br, and after researching extensively I was a little worried/odd feeling, but the reason I stopped the test at 30.4 and didn't go any higher was because I was getting very, very slight ejector marks, but a pretty hard/stiff bolt lift at 30.4 and I stopped at 30.6.

I'll go back out and reshoot 29.8-30

Over 30g in the BR IMHO is just not worth it, its starts getting hard on brass. Do you know how much free bore your barrel has?

 

[Dildobaggins]

Over 30g in the BR IMHO is just not worth it, its starts getting hard on brass. Do you know how much free bore your barrel has?

I believe it's .94 or .93 I had the reamer print picture on my phone from a different forum.

 

[LR1845]

I believe it's .94 or .93 I had the reamer print picture on my phone from a different forum.

Thats a short free bore .104 is pretty standard and I think .130 or .135 is popular...my reamers in BR and BRA were both .145 because I found I had better groups and consistency over the life of the barrel with big jumps. I think with .98 free bore and 30g of varget you'll start to compress around .030-.040 off the lands.

 

[Dildobaggins]

Thats a short free bore .104 is pretty standard and I think .130 or .135 is popular...my reamers in BR and BRA were both .145 because I found I had better groups and consistency over the life of the barrel with big jumps. I think with .98 free bore and 30g of varget you'll start to compress around .030-.040 off the lands.

It's off the internet, so take that for what you will haha. I'm going to be doing another 6br or 22 br this summer. I will keep that in mind!

 

[LR1845]

Where did you get your barrel from? Just curious.

 

[Dildobaggins]

Where did you get your barrel from? Just curious.

It's a criterion prefit from NSS

 

[Precision Underground]

I agree but in most cases the more rounds that are shot the more shooter error comes into play...I personally am not a group shooter and do not know many ppl that can shoot group after group weather its round robin or just groups.

But shooting RR is not shooting groups at all. It’s basically doing dot drills. That’s the whole point of shooting RR. If you end up with a clear pattern on target as the OP did you can take it to the bank.

 

[Precision Underground]

Quick notes. I did shoot round robin. So this is my first 6br, and after researching extensively I was a little worried/odd feeling, but the reason I stopped the test at 30.4 and didn't go any higher was because I was getting very, very slight ejector marks, but a pretty hard/stiff bolt lift at 30.4 and I stopped at 30.6.

I'll go back out and reshoot 29.8-30 because I'm absolutely 100 percent confident that the other groups were not pulled and shot well. If the others group/poi the same, then I'll leave them, and load 29.6

Me seeing a guy who shot his OCW round robin AND used a PURG bag.


Really though if you shot that test RR, 29.5-29.6 is your OCW… 100%. Your fire forming groups showed the same result for 30+ and you've got pressure at 30.4 so there’s nowhere to go.

 

[LR1845]

But shooting RR is not shooting groups at all. It’s basically doing dot drills. That’s the whole point of shooting RR. If you end up with a clear pattern on target as the OP did you can take it to the bank.

I am not arguing with you but if you think about it the OCW IS shooting groups just a different way of doing it...if I am shooting 5 dots with 1 round then going back and shooting 1 round at each dot again for 3(or how ever many you decide to use)total rounds at each dot and trying to get every round shot at that dot through the same hole or as close as I possible can for the best group/groups seems to me like I'm shooting groups.

Everyone has their favorite way of shooting load development I've shot most of them over the years and personally I don't think there is any perfect way its what you find works best for you and your needs.

 

[Dildobaggins]

I'll throw one more variable into the equation. I shot the fireforming loads in groups of 5 and did not do RR. When I did the OCW test I did do RR. I need to better explain myself. My bad!

 

[LR1845]

I'll throw one more variable into the equation. I shot the fireforming loads in groups of 5 and did not do RR. When I did the OCW test I did do RR. I need to better explain myself. My bad!

And what do you feel you shoot better groups or the round robin?

 

[MarkyMark007]

OP do yourself a favour and read this thread:

I'll Post This Here - Hornady's Podcast #50. I thought it was one of their best, but some reloaders might not like what they see....

Hornady podcast #50. Another in their ongoing long series on ballistics. This one focuses on things like SD and Velocity stats that reloaders tend to focus on, and why the statistics tend to prove that those things might not be as relevant as we all think.... A hard pill to swallow for some of...

www.snipershide.com

and stop halucinating about 'nodes', 'OCW', 'ladder'...

 

[Doom]

Newberry's OCW as explained by Dan himself was brought about by seeking a method to reload ammunition similar to those manufactured rounds (esp. FGMM) that seemed to shoot accurately out of almost every rifle. He concluded that the rounds were not overly sensitiveve to powder charge. He developed the method to seek a charge that was accurate over a range of loads (same/similar Point of impact) and of acceptable accuracy. It is not a ladder test. To achieve his loading he devised a three shot per load increment test shot round robin at 100yds to avoid having things such as barrel condition and temperature, and environmental factors such as wind affecting the groups point of impact. Using more than 3 shots in my experience doesn't improve the test. The system is not based on group size for evaluation although some info might be obtained from comparing groups. The evaluation criteria is based on average point of impact between groups of differing loads. It is important to note that unlike chronograph data the results are based on target impacts and represent the rifle system performance, including the shooter. As to whether the results are a "node" is left to the tester. It does produce a range of loads with very similar points of impact at 100yds and beyond for the tested seating depth.

It is important that the shooter pay attention to his setup. In particular in warm conditions where the shooter might move away from the rifle while it cools, it important to get back on the rifle with the same setup and followthrough. If not, then the groups open up but it's detectable as all points will usually shift. I will also add that the loads developed will typically shoot smaller groups than those shot during the test. This seems to be due to repeatability issues with shooting round robin.

As to the statistical significance of the data, in general the system uses 9 shots as a minimum to indicate similar points of impact over three or more load increments. Based on my own personal experience with the method it works. By using average point of impact all nine or more shots are included in the evaluation. The loads developed this way are repeatable. Are they the only loads that are acceptable? That's a question for others to determine. I have one load in 223 that has an almost identical accuracy and point of impact with a seating depth of 2.200" and 2.250".

A word of caution. The OCW method may for may not produce the most accurate load from a rifle. It will produce an accurate, repeatable load.

 

[Precision Underground]

I am not arguing with you but if you think about it the OCW IS shooting groups just a different way of doing it...if I am shooting 5 dots with 1 round then going back and shooting 1 round at each dot again for 3(or how ever many you decide to use)total rounds at each dot and trying to get every round shot at that dot through the same hole or as close as I possible can for the best group/groups seems to me like I'm shooting groups.

Everyone has their favorite way of shooting load development I've shot most of them over the years and personally I don't think there is any perfect way its what you find works best for you and your needs.

No argument taken, you’ve got to be a precision rifle geek to care about this stuff enough to discuss it so we’re all cut from similar cloth. That being said, I’m a round robin nazi and am in a boring meeting so buckle up lol.

Shooting round robin(correctly) isn’t like shooting groups at all. Shooting groups is getting set up and firing a string of rounds at a single target without breaking position. Shooting RR should be done by building a new position on a different target for every shot. Sure the object is to have groups on target at the end, but…….each round in each “group” comes from its own position. That’s the important part

What this does is take the variations in the shooter’s setup (the shooter’s influence on the rifle) and spreads them out evenly across the test vs injecting them into single groups separately. If you have a consistent/quality set up RR won’t make much difference in what your target looks like. If you don’t have a consistent set up the target will be a mess and won’t tell you much at all. So it’s a good way to set your test up so that gives you a clear result only if you shoot well and don’t cause shooter induced movement on target. If variations in your position change your POI you’ll have a mess of a target at the end of round robin. This is a good thing bc I’d rather have no conclusion than a false conclusion.

This is why a lot of ppl don’t shoot RR or shoot it once and then abandon it. They can’t set up consistently enough to get a clear result. They don’t like this so they just shoot groups instead. When they shoot separate groups the “result” on target appears to be more clear bc variations in their set up are injected into each group separately and some smaller groups will typically happen. This is why some ppl say shooting groups “works better” for them. It is better at providing “groups” to look at but it doesn’t work better to find the OCW. 9/10 times the movement on target is induced by their set up rather than by the change in charge weight. Whatever group they happened to get square and focused on becomes their “optimal charge weight” because it’s the smallest group for the day.

 

[Doom]

No argument taken, you’ve got to be a precision rifle geek to care about this stuff enough to discuss it so we’re all cut from similar cloth. That being said, I’m a round robin nazi and am in a boring meeting so buckle up lol.

Shooting round robin(correctly) isn’t like shooting groups at all. Shooting groups is getting set up and firing a string of rounds at a single target without breaking position. Shooting RR should be done by building a new position on a different target for every shot. Sure the object is to have groups on target at the end, but…….each round in each “group” comes from its own position. That’s the important part

What this does is take the variations in the shooter’s setup (the shooter’s influence on the rifle) and spreads them out evenly across the test vs injecting them into single groups separately. If you have a consistent/quality set up RR won’t make much difference in what your target looks like. If you don’t have a consistent set up the target will be a mess and won’t tell you much at all. So it’s a good way to set your test up so that gives you a clear result only if you shoot well and don’t cause shooter induced movement on target. If variations in your position change your POI you’ll have a mess of a target at the end of round robin. This is a good thing bc I’d rather have no conclusion than a false conclusion.

This is why a lot of ppl don’t shoot RR or shoot it once and then abandon it. They can’t set up consistently enough to get a clear result. They don’t like this so they just shoot groups instead. When they shoot separate groups the “result” on target appears to be more clear bc variations in their set up are injected into each group separately and some smaller groups will typically happen. This is why some ppl say shooting groups “works better” for them. It is better at providing “groups” to look at but it doesn’t work better to find the OCW. 9/10 times the movement on target is induced by their set up rather than by the change in charge weight. Whatever group they happened to get square and focused on becomes their “optimal charge weight” because it’s the smallest group for the day.

OK, straped in and ready for launch! I personally had never dug deeply into all of the aspects of shooting RR but based on my experience and having worked with others your analysis reflects my experience. I typically use target points that are about 3-1/2" on center when shooting at 100yds so It essentially requires a new setup, but uses the same bench/seating position. In summer when temps are above 90F here I will usually get up and move around while waiting on the barrel to cool. I initially found that when I would go back to shooting that the POI would move and be obvious on the first shot. When that would happen, it was important to fight the urge to correct the position which will skew the groups.

Guess I'm a RR nazi at heart!