My OCW Test

Reloading equipment, methods, load data, powder and projectile information.

My OCW Test

Post by Berto » 04 Jan 2018, 1:11 pm

Hi there, here is a picture of my OCW Test that i am hoping to get some help with analysisng. As i dont want to make a mistake and begin reloading the wrong charge. I believe my node is at 37.4 grains and that i should fiddle with seating depth or perhaps a different primer to try bring the groups together. Thoughts?
Attachments
Reloading.jpg
Reloading.jpg (701.33 KiB) Viewed 7415 times
Berto
Recruit
Recruit
 
Posts: 7
Victoria

Re: My OCW Test

Post by brett1868 » 04 Jan 2018, 10:21 pm

Maybe as a first post you'd like to introduce yourself but I understand the desire for answers :) For others reading the thread, the rifle is a .243,CCI LR Primer, Norma brass, AR2208 and Hornady 75gr V-Max projectiles.
Rather then jump in at 37.4gr maybe try seating a fraction closer to the lands on the 36.8 & 38gr loads, by all means load up some 37.4gr loads to try as well. I personally like Federal Match primers or CCI BR2 as I find the standard CCI primers inconsistent.
What is the intended target cause a 75gr projectile might be a bit light for bigger game. Also what's the make, model, Twist and barrel length of the rifle?

(I'm not psychic, I was the mod that approved your post on FB this morning :) :)
How's my posting?
Complaints, Concerns - 13 11 14
User avatar
brett1868
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 3017
New South Wales

Re: My OCW Test

Post by bladeracer » 04 Jan 2018, 10:41 pm

Berto wrote:Hi there, here is a picture of my OCW Test that i am hoping to get some help with analysisng. As i dont want to make a mistake and begin reloading the wrong charge. I believe my node is at 37.4 grains and that i should fiddle with seating depth or perhaps a different primer to try bring the groups together. Thoughts?


I'd be working on the 36.8gn load a bit more. I don't see any need to load hot so if you can get that sort accuracy at 36.8gn I'd go with that.
I'm not a fan of basing these decisions on just a three-shot group with each charge though.
I'd try at least ten of each to nail down an area to focus on.
Practice Strict Gun Control - Precision Counts!
User avatar
bladeracer
Field Marshal
Field Marshal
 
Posts: 12655
Victoria

Re: My OCW Test

Post by Stix » 04 Jan 2018, 11:08 pm

Im probably to under qualified to pass comment, but ill do so anyway because im at eork with nothing better to do...!...

The way i see it, id be initially going with the 36.8 & 38 loads...
& as BR says, the lower charge if it works out--unless there is some miraculous velocity increase for the 38gr load over the 36.8--

Im not sure why the 37.4 is of interest unless its an elevation thing you're chasing & you've knowingly badly pulled (or wind has thrown) the fliers on the 37.2 & 37.6...

Can i ask what reasoning is behind the 37.4 interest...?
I dont know what conditions were, tange etc when you shot it.
The man who knows everything, doesnt really know everything...he's just stopped learning...
Stix
Colonel
Colonel
 
Posts: 3675
South Australia

Re: My OCW Test

Post by Stix » 04 Jan 2018, 11:16 pm

brett1868 wrote:(I'm not psychic, I was the mod that approved your post on FB this morning :) :)


:lol:
The man who knows everything, doesnt really know everything...he's just stopped learning...
Stix
Colonel
Colonel
 
Posts: 3675
South Australia

Re: My OCW Test

Post by Apollo » 04 Jan 2018, 11:38 pm

To me that is not an OCW Test... It's just a group test as such.

There is a lot of information and results available to show what an OCW Test is about and shows, if that is a test you believe carries some weight to belief and result. Sorry, but I don't believe it shows much as far as Target Shooting goes. OCW, one shot over many different powder loads and see where the "Node" is... then what, how do you improve...by shooting groups of shots in that zone and work from there.

What I see in the initial post is just a powder load test using 3 shots, nothing to do with OCW. Fine, as long as the barrel was fouled before the first group. Then go on and look at the shape of the groups, as long as the shooter is experienced and can exclude shooter error for bad placement.

The best group is the 38gr being the closest to a circular group with little verticle / horizontal. It could be tightened up some if that is at 100 metres. A good .243W at 100 metres using what should be near ideal for a 1:10 Twist Barrel which most are, using the ideal 70/80 grain bullets really should be one small clover leaf hole. That is using high quality grade bullets, like Berger. Not some cheap rubbish.

If I was instructing, working up a load and keeping in mind that a .243W is a Barrel Burner, I would go with the 38gr Load and just tweak a few things, like seating depth.

Target shooting I do, with a .243W but at 300 Metres and I use Berger 90gr BT Bullets with AR2209 and it that has won a couple of times. I'd use the same for general hunting, BUT shorter range the 70/80 Grain Bullets (Berger) shine with AR2208.

Just my view and experience over the past 40 odd years.

BTW... I found the best results I have had in a Tikka T3 or Sako 85 was using CCI BR2 Primers. ie Tightened my groups. Best of luck.
Apollo
Warrant Officer C1
Warrant Officer C1
 
Posts: 1327
New South Wales

Re: My OCW Test

Post by tom604 » 04 Jan 2018, 11:42 pm

bladeracer wrote:
Berto wrote:Hi there, here is a picture of my OCW Test that i am hoping to get some help with analysisng. As i dont want to make a mistake and begin reloading the wrong charge. I believe my node is at 37.4 grains and that i should fiddle with seating depth or perhaps a different primer to try bring the groups together. Thoughts?


I'd be working on the 36.8gn load a bit more. I don't see any need to load hot so if you can get that sort accuracy at 36.8gn I'd go with that.
I'm not a fan of basing these decisions on just a three-shot group with each charge though.
I'd try at least ten of each to nail down an area to focus on.


TEN !!!are you crazy!! :sarcasm: nine will do :lol: three groups of three :thumbsup: 36.8 would do me but you could try 36.6 or 37 again nine shots just to make sure, why do you think 37.4? they are only just closer to the bull and only then if you discount the flyers (should of put an extra shot in) also what range were you shooting? :unknown: guessing 100?
adi powders are temp stabilised so i wouldn't think that it will make that much difference :allegedly: let us know how you go :thumbsup:
User avatar
tom604
Warrant Officer C2
Warrant Officer C2
 
Posts: 1053
South Australia

Re: My OCW Test

Post by Berto » 05 Jan 2018, 7:19 am

brett1868 wrote:Maybe as a first post you'd like to introduce yourself but I understand the desire for answers :) For others reading the thread, the rifle is a .243,CCI LR Primer, Norma brass, AR2208 and Hornady 75gr V-Max projectiles.
Rather then jump in at 37.4gr maybe try seating a fraction closer to the lands on the 36.8 & 38gr loads, by all means load up some 37.4gr loads to try as well. I personally like Federal Match primers or CCI BR2 as I find the standard CCI primers inconsistent.
What is the intended target cause a 75gr projectile might be a bit light for bigger game. Also what's the make, model, Twist and barrel length of the rifle?

(I'm not psychic, I was the mod that approved your post on FB this morning :) :)


Small World! Yes sorry i am new to reloading but i have done a lot of reading and yoitube watching on what they call the OCW Method. All the above infomation is correct and i am shooting a stainless steel tikka t3 forest at 100 yards. The reason im thinking about 37.4g is that the OCW test states you are looking for verticle spread and not counting the horizontal spread as it could be shooting error or a bulket seating issue. Bit as for horizontal spread i would assume that 37.4 or 37.6 itself would have the smallest standard deviation.

Im using the 75grain progectile as a varmit rifle but regardless i want the best accuracy possible, i believe the bullet we used to hunt should be as good or better than we use on targets.

Also the photo is side ways, its should be looked at with the grain ammounts on top.
Berto
Recruit
Recruit
 
Posts: 7
Victoria

Re: My OCW Test

Post by Berto » 05 Jan 2018, 7:21 am

Apollo wrote:To me that is not an OCW Test... It's just a group test as such.

There is a lot of information and results available to show what an OCW Test is about and shows, if that is a test you believe carries some weight to belief and result. Sorry, but I don't believe it shows much as far as Target Shooting goes. OCW, one shot over many different powder loads and see where the "Node" is... then what, how do you improve...by shooting groups of shots in that zone and work from there.

What I see in the initial post is just a powder load test using 3 shots, nothing to do with OCW. Fine, as long as the barrel was fouled before the first group. Then go on and look at the shape of the groups, as long as the shooter is experienced and can exclude shooter error for bad placement.

The best group is the 38gr being the closest to a circular group with little verticle / horizontal. It could be tightened up some if that is at 100 metres. A good .243W at 100 metres using what should be near ideal for a 1:10 Twist Barrel which most are, using the ideal 70/80 grain bullets really should be one small clover leaf hole. That is using high quality grade bullets, like Berger. Not some cheap rubbish.

If I was instructing, working up a load and keeping in mind that a .243W is a Barrel Burner, I would go with the 38gr Load and just tweak a few things, like seating depth.

Target shooting I do, with a .243W but at 300 Metres and I use Berger 90gr BT Bullets with AR2209 and it that has won a couple of times. I'd use the same for general hunting, BUT shorter range the 70/80 Grain Bullets (Berger) shine with AR2208.

Just my view and experience over the past 40 odd years.

BTW... I found the best results I have had in a Tikka T3 or Sako 85 was using CCI BR2 Primers. ie Tightened my groups. Best of luck.



What is your understanding of the OCW test?
Berto
Recruit
Recruit
 
Posts: 7
Victoria

Re: My OCW Test

Post by Berto » 05 Jan 2018, 7:26 am

Also if adjust the bullet seating depth and 37.2 and 37.6 close up dramatically then i would assume the 36.8 and 38 would incrase in horizontal spread but keep there verticle spread
Berto
Recruit
Recruit
 
Posts: 7
Victoria

Re: My OCW Test

Post by tom604 » 05 Jan 2018, 8:23 am

just had a read of newberrys load system,,use a lot of ammo for a "stable" load, then use more to try and get it to group,you have two groups that already group so why not tweak those? were you using a lead sled/rest to remove flyers? what is your understanding of the ocw test and what do you want to achieve,not a target shooter myself so i am curious :thumbsup:
User avatar
tom604
Warrant Officer C2
Warrant Officer C2
 
Posts: 1053
South Australia

Re: My OCW Test

Post by sungazer » 05 Jan 2018, 8:30 am

There is some great advice in here. I tried a similar test with my rifle and while a lot of people believe in these ladder test. (That is what you are doing trying to find the point where the elevation changes the least for a given powder change.) I felt that the tests that I did (which went up in 0.1 gr and a lot of shots) any information was lost in the noise of the results. You need to write down all the factors that could cause an error in your results. You don't have to just add these up to get an error bar. A simple way is to square each error add all of those and take the Sqrt. If you want to really get into stats thats another thing.Anyway I think you will find like me for a true ladder test the error is greater than the result. You are better off shooting some some multiple groups and different loads. Then vary the seating depth You would need to specify the bullets you are using or want to use to for depths to explore.
For my 243 being a barrel burner I dont get to worked up about extreme accuracy as they are inherently anyway really have just tried a few groups and seated either as close to the lands for secants or 20 thou off for hybrids or tangents.
sungazer
Sergeant Major
Sergeant Major
 
Posts: 1525
Other

Re: My OCW Test

Post by bigfellascott » 05 Jan 2018, 9:59 am

If the rifle is only for hunting, just go with the 38gn load and go shoot fur! No need to stuff around worrying about crap that won't effect your hunting (why waste time and money for no real benefit) if it's for target shooting then proceed!
User avatar
bigfellascott
Lieutenant General
Lieutenant General
 
Posts: 5289
-

Re: My OCW Test

Post by Cooper » 05 Jan 2018, 11:05 am

Berto wrote:
Also the photo is side ways, its should be looked at with the grain ammounts on top.



Berto your hurting my head! I did happen to see your post on Facebook. When I saw your post on here it did appear that the target was now horizontal rather than vertical as it was on Facebook. So I am kind of quessing that the target is now in its correct orientation given that the grain increments are written on top.

I'd go with 36.8gr. But 38.0 also looks pretty good.
Cooper
Sergeant
Sergeant
 
Posts: 539
Victoria

Re: My OCW Test

Post by sungazer » 05 Jan 2018, 11:21 am

I would repeat the 37.2 and see if that horizontal shot repeats itself other wise you have good vertical and good vertical on each side of you. This is what you are looking for somewhere in the middle where a little bit of velocity difference doesn't cause a vertical shift.
sungazer
Sergeant Major
Sergeant Major
 
Posts: 1525
Other

Re: My OCW Test

Post by Wm.Traynor » 05 Jan 2018, 1:57 pm

Berto,
Is the horizontal dispersion a result of wind variations?
Wm.Traynor
Sergeant Major
Sergeant Major
 
Posts: 1644
Queensland

Re: My OCW Test

Post by Oldbloke » 05 Jan 2018, 2:15 pm

bigfellascott wrote:If the rifle is only for hunting, just go with the 38gn load and go shoot fur! No need to stuff around worrying about crap that won't effect your hunting (why waste time and money for no real benefit) if it's for target shooting then proceed!


I agree 38 Or 36.8
The greatest invention in the history of man is beer.
https://youtu.be/2v3QrUvYj-Y
Member. SFFP, Shooters Union.
SSAA, the powerful gun lobby. :lol: :lol: :lol: :lol:
Hunt safe.
User avatar
Oldbloke
Field Marshal
Field Marshal
 
Posts: 11192
Victoria

Re: My OCW Test

Post by Berto » 05 Jan 2018, 5:07 pm

Wm.Traynor wrote:Berto,
Is the horizontal dispersion a result of wind variations?


Its wasnt windy but it was hot so if it wasnt me it could have been the heat mirage rhat threw me?

I have since reshot the grp at 37.6 and there is far less horizontal spread
Berto
Recruit
Recruit
 
Posts: 7
Victoria

Re: My OCW Test

Post by Berto » 05 Jan 2018, 5:22 pm

37.6 shot again
Attachments
take 2.jpg
take 2
take 2.jpg (44.89 KiB) Viewed 6220 times
Berto
Recruit
Recruit
 
Posts: 7
Victoria

Re: My OCW Test

Post by tom604 » 05 Jan 2018, 5:40 pm

should of tried 36.8 or 38 again as well, if it was the heat that caused the spread on 37.6 and then it tightened up that much those two groups should pin hole :D
what rest were you using ? did you try any other loads? nosy bugger arn't i :lol: :thumbsup:
User avatar
tom604
Warrant Officer C2
Warrant Officer C2
 
Posts: 1053
South Australia

Re: My OCW Test

Post by sungazer » 05 Jan 2018, 6:10 pm

Should of shot the 37.2 again if you were the fault of the horizontal at 37.6 it was probably the same fault at 37.4 other have said go for the outlies due to better looking groups again I would suggest you go for the mid range 37.4 as you have good groups on each side, where fliers are less likely to happen. You can see what I meant about the true results getting lost in the noise of errors.
sungazer
Sergeant Major
Sergeant Major
 
Posts: 1525
Other

Re: My OCW Test

Post by Berto » 05 Jan 2018, 6:20 pm

37.8 shot similar to 37.6 in the retest, 37.4 had a bit of verticle spread but im blaming that on me.

I think ill be trying some seating depths at 37.6 as it appears i have a rather long node and it is rather stable either side
Berto
Recruit
Recruit
 
Posts: 7
Victoria

Re: My OCW Test

Post by bladeracer » 05 Jan 2018, 6:24 pm

Berto wrote:I have since reshot the grp at 37.6 and there is far less horizontal spread


That's exactly why I wouldn't be making these decisions based on three rounds of each load.
How do you know the other groups are truly indicative if you haven't shot any more than those three rounds?
Practice Strict Gun Control - Precision Counts!
User avatar
bladeracer
Field Marshal
Field Marshal
 
Posts: 12655
Victoria

Re: My OCW Test

Post by sungazer » 05 Jan 2018, 6:35 pm

The theory is that charge weight is only responsible for vertical spread. The ability to group is all based on seating depth. A lot of people will only shoot one shot at each charge normally a bit closer together based on others experience or velocities wanted. then a flat spot selected and that charge weight then shot at different seating depths to look for grouping. Lots of theories out there with some guns you cant afford to shoot lots in load development unless you purchase 6 barrels and have them all chambered at the same time and then also grade barrels.
sungazer
Sergeant Major
Sergeant Major
 
Posts: 1525
Other

Re: My OCW Test

Post by bladeracer » 05 Jan 2018, 6:38 pm

sungazer wrote:The theory is that charge weight is only responsible for vertical spread. The ability to group is all based on seating depth. A lot of people will only shoot one shot at each charge normally a bit closer together based on others experience or velocities wanted. then a flat spot selected and that charge weight then shot at different seating depths to look for grouping. Lots of theories out there with some guns you cant afford to shoot lots in load development unless you purchase 6 barrels and have them all chambered at the same time and then also grade barrels.


True, but if you own a rifle like that it generally drops all the bullets through one hole so you don't need groups to know where it's shooting.
If you can't shoot that consistently though then you need to shoot a much larger sample to determine the potential of each charge weight - including horizontal and vertical displacement.
Practice Strict Gun Control - Precision Counts!
User avatar
bladeracer
Field Marshal
Field Marshal
 
Posts: 12655
Victoria

Re: My OCW Test

Post by marksman » 05 Jan 2018, 9:02 pm

this is a true OCW test
what Apollo is referring to is the Audette ladder system
I recon your pretty close with what you have :thumbsup:
“If you do not read the newspapers you are uninformed. If you do read the newspapers you are misinformed”. Mark Twain
User avatar
marksman
Colonel
Colonel
 
Posts: 3660
Victoria

Re: My OCW Test

Post by Gwion » 05 Jan 2018, 9:50 pm

I'm with Brett. Load up a bunch at 36.8 and 38 to confirm. Personally the 38 looks the best but not enough data to know for sure. You need a few more 5 round groups to get a good indication. Some times you fluke a good group just like sometimes you shank a flyer. That is, it's not uncommon to actually pull a shot into the group that would have been a flyer if your aim was true.
Numbers count when it comes to averages.
User avatar
Gwion
Colonel
Colonel
 
Posts: 3978
-

Re: My OCW Test

Post by straightshooter » 11 Jan 2018, 7:27 am

This whole exercise seems like a waste of time to me. Similarly with some of the attendant advice offered.
So the rifle is intended for hunting, right.
Shoot a numerically significant group, like at least 10 shots, at 200 yards or meters or at your preferred zero range depending on what you have access to.
Then adjust your scope to correctly center it for that group and your desired trajectory.
Then fire a confirmation group.
If the confirmation group shows that you have done things right and provided you don't do any further tinkering, then you can happily pack up and proceed to a successful hunting career.
Don't give a second thought at all to the actual group size because in reality, over a sufficiently large sample size, no amount of minor tinkering will improve it.
An appreciation of statistical analysis would help to grasp why.
Unfortunately many people cherry pick and fall in love with factors they believe will improve accuracy while ignoring or being totally ignorant of other factors that swamp the effects of their preferred minor adjustments.
In your case for example you have chosen 2208 for a 75 grain projectile in a 243. This results in a loading density of at best about 80%. You will thus inherently have significantly greater variations in ignition and pressure and chances are that this will overwhelm the effects of tinkering with minor variations in charge weight or seating depth.
"Anything is possible if you don't know what you are talking about."
"There is no expedient to which a man will not resort to avoid the real labor of thinking." Sir Joshua Reynolds
straightshooter
Warrant Officer C1
Warrant Officer C1
 
Posts: 1263
New South Wales

Re: My OCW Test

Post by in2anity » 12 Jan 2018, 9:54 pm

Did you have few minutes break between groups? What sort of rest were you using? Did you only shoot a group of 3 per increment? Was there any wind? Are you a good shot?(I.e. can you rule out human error)

Point is, IMO three shots per increment is not a big enough sample size to identify trends. I say run the test again and see if the results are the same. And then do it again, even try 5 shot groups.
At what point does lack of maintenance become patina?
User avatar
in2anity
Lieutenant Colonel
Lieutenant Colonel
 
Posts: 3048
New South Wales

Re: My OCW Test

Post by marksman » 13 Jan 2018, 10:23 am

I'm usually cocky enough that if when I do an OCW test if 2 holes are way apart I wont shoot the third and move to the next
saves my barrel life, I never do more than 3 shot testing, if it don't work for 3 shots its not going to for 5 or 10
when finished and have decided what I want to explore I will definitely reshoot what I call the OCW as well as just above and just below to verify the OCW
exactly how you are supposed to do when doing an OCW, there is usually more than one load you would want to explore
I have seen too many people who don't verify then call the OCW a waste of time when there load does not perform
after shooting this load for a while you will need to retune your loads as well as retweek your rifle, its called maintenance
“If you do not read the newspapers you are uninformed. If you do read the newspapers you are misinformed”. Mark Twain
User avatar
marksman
Colonel
Colonel
 
Posts: 3660
Victoria

Next

Back to top
 
Return to Reloading ammunition