OCW Loading Technique

[@Rico11b]

This is an all day event when you consider the time it takes to cool the barrel between strings. I'd feel better doing 5 shots per powder load. That way I don't have to go back and confirm with additional testing later on.

[@scorch101]

Agreed. I have found that even 2-3 per load to determine a node followed on the next trip with a 5 shot confirmation load of the node usually works.

[@josevelez7539]

Good video!

[@scorch101]

Thanks Jose.

[@58harwood]

Actually the video is very misleading and flat wrong in many of its assumptions and leaps to conclusions! Like I said, “clueless!”

[@bigbore4459]

Did you mention where to start seating depth?

[@scorch101]

Sorry, no. Perhaps I should do an entire video on determining seating depth. Short answer is once you know your chamber dimensions and where the bullet touches the lands, I start at 20 thou back (if possible, due to magazine limitations) and start playing around forward and backwards from there.

[@charlesking8542]

OCW is a method coined by Dan Newberry and does not involve a chono, only stable poi.

[@scorch101]

Granted that Dan Newberry may have been the first to "coin" the term OCW, however it has evolved over time to encompass a method to try to determine the best charge weight and powder for a particular rifle, bullet, brass, primer and powder combination. My method tries to minimize the number of rounds by using both POI and velocity distribution. The thought here, ( and I am not the originator of this thought) is that dispersions in POI and dispersions in velocity are both related to the resonance of that combination of constituents. Finding the best or optimum charge weight such that the barrel is at a node or "least deflected" point when the bullet exits the barrel is the aim of the search. By combining both POI and velocity spread for a given charge weight you get to consider two factors to determine the optimal charge weight. If the POI spread and the SD occur at the same load, you may have found the node. A five shot grouping at that node + or - .1 or .2 grains would be the confirmation test.

[@58harwood]

@@scorch101 Your method, and Dan’s method, are statistically flawed, the sample sizes are way to small to be of any meaningful use in any way! Garbage in, garbage out! 👍

[@scorch101]

@@58harwood you see 58 you can post a useful text. This might surprise you but I mostly agree with you on the statistical value of this method. I find it useful to screen powders and loading without having to generate large amount of data. Recently I have combined this with Gordon’s reloading tool with the additional screen of no powder charge that has less than a minimum 90% case fill AND 100% powder burn. This may not tell you the best load but it will tell you the powder/charge combinations that are not worth trying.

[@58harwood]

All I’m saying is, like Astrology, many can see trends and supposed “nodes” when and where you want too! There is an implicit bias in the interpretation of the limited “data”. Look, I was the poster child for the OCW and Satterlee methods! In retrospect, I couldn’t have been more naïve, wrong or embarrassed! Just saying………

[@charlesking8542]

@@58harwood There are several versions of OCW, all of which are aimed at showing where the point of impact (not group size) is stable within a charge weight range. If you cannot see a very clear node on this basis, then you have a significant issue at hand. All these approaches are based on positive compensation, and in fact the barrel harmonic frequency can be determined by this type of test. It is quick, easy, and reproducable.

[@MrBigcharl]

Is it possible to share the spead sheat you use if i send you an email address

[@scorch101]

No problem. I will create a blank sheet. I have one for each cartridge that I load for. If you have a particular favorite that you wish to try, let me know and I will send a blank one for that cartridge.

[@FrancoisCloete]

I would also apprecaite a. spreadsheet for the 6.5 Creedmoor.

[@scorch101]

@@FrancoisCloete No problem, I just need an email address to send it to.

[@scorch101]

@@FrancoisCloete you can send me your email address to send the Excel file to [e-mail]

[@scorch101]

MrBigcharl you can send me your email address to send the Excel file to [e-mail]

[@terrycalvert7812]

Yeah and every time you repeat that velocity test it changes every single time

[@scorch101]

Ok, so I am not sure of your point. This is the reason you do OCW and validate with SD and ES. Am I missing something in your comment?

[@terrycalvert7812]

@@scorch101 Just stating that me and several other people have done the satterly method of load development to find the flat spots in velocity and every time you do that test the flat nodes are in a different spot every time sometimes they are close but never ever the same place twice. Iv seen a flat spot at example 45 grains repeat the test and that spot would move to 45.8 grains the OCW portion of your video is statistically a sound method but the velocity testing to find flat spots is worthless. Brian litz has a podcast with Eric cortina where they talk about this method to find loads and also have found the same thing iv noticed when trying to find a load this way.

[@scorch101]

@@terrycalvert7812 Thanks for the response. The method I mentioned in this video, uses both velocity and Point of impact to determine nodes. After you think you have a node then you still need to do confirmation loads of greater numbers around those nodes to make sure that your SD and ES are low. Preferably in the single digits or teens.

[@PaulWilliams-l7x]

@@terrycalvert7812 I have found the very same thing and it has me puzzled what to do next. A very low ES and SD node over a few different 0.2 grain weights one day, then 3 days later, totally different ES and SD's at the same charges. Any advice would be greatly appreciated. Cheers

[@terrycalvert7812]

@@PaulWilliams-l7x the method iv had the most success with is the ladder test where I focus more on flat spots in impact at further distance say 500 and on out to even a 1000 yards! Shoot 2 shots at each charge and you will find normally a grain spread where all 6 of those shots will be within a cpl inches of each other the others will be spread out much more than your node then I load in the middle of that grain spread and do seating depth testing! After seating depth you might still need to play with powder charge a cpl tenths one way or the other just to see if the load can be improved a lil more! Iv also found with this method that I find a much more stable load that’s a lot more tolerable to temp changes and environmental conditions!! Long range only has a great video going through every step of this form of load development it’s about an hour long but if you want to learn how to do a ladder test and get the most out of it I’d watch it a cpl times and write things down there isn’t a better video I know of showing how to do a ladder test!!

[@davidnuttall-y7l]

You have used two methods to determine optimum powder weight and that is OCW & LADDER METHODS Also why don't you demonstrate how to determine OCW using each target and compare each while you talk about it.

[@scorch101]

Good idea. I will try to incorporate some of your suggestions in a future video.

[@58harwood]

Because reading 3-5 shot OCW groups is akin to reading tarot cards! You can literally see whatever you want to see! I used the OCW method for years, was a big fan until the Hornady podcast showed the error in my thinking. OCW works to a degree but the Hornady method, backed by sound statistical evidence is a more reliable method and often quicker finding a load.

[@scorch101]

@@58harwood I agree the more data the better, but to get to a statistically valid solution requires more time and money than most people can afford. My point in my reply to you is that most of the people that I encounter that are gun owners, whether they be a the range or a competition are the nicest and most helpful people you would want to hang out with. Somehow when people get on the internet they seem to lose all civility and start acting like an a_ _. I appreciate good responses, the ones that are not helpful and in fact just demeaning will be responded to with tongue in cheek sarcasm and ridicule.

[@58harwood]

@@scorch101 But in the end it’s not “more time and money” than going the OCW route. That’s the common misconception that is not true! A 5 shot 5 group OCW test is a minimum of 25 rounds. And what do you have to show for it? Garbage in, garbage out! Any single 5 shot group is not diagnostic by themselves. You just shot 25 rounds and all of that data is suspect, incomplete, not all that reliable. Typically I’ll load one 5 shot test first, sometimes I’ll do a 10 shot group first but, the total number of shots always adds up to 30 rounds minimum total..If I get a flyer with the initial 5 shot group and the group already exceeds my expectations, I move on. If it looks possible/promising, I’ll go load another 25 rounds and shoot them over the first 5 shot group. So, I’ve used 30 rounds, you’ve used 25. However, your data points are incomplete, not that useful, lacking, not reliable. Whereas the one 30 shot group I shot is statistically more valid, more diagnostic. So, who’s really wasting time and ammo? The 5 shot, 5 group OCW test is statistically just a crap shoot. IMO 😎

[@scorch101]

@@58harwood I value your opinion, just try to be civil about it. Saying someone is clueless is classless.

[@rotasaustralis]

Sorry, but ladder testing using 1,2 or three rounds per charge weight has been thoroughly debunked I'm afraid. Even if ladder testing was a reality, relatively moderate changes in powder temp will throw the entire ladder out of whack anyhow. The whole ladder testing BS was thought up or, at least propounded by a guy who was a good shooter but, had no idea about shot to shot variation or how to correlate it. The idea has been bandied about for years & caught on fast because of the big names pushing it blindly.

[@rotasaustralis]

@@lngrange8912 It's the same thing with a slightly different focus which, is a another non event because it uses the same lack of data points & draws a similarly irrelevant conclusion. It would be worth your time to do a little study on the subject of statistical relevance & how to achieve it.

[@rotasaustralis]

@@lngrange8912 That's the very problem though. The data seems to be representative but, it isn't, at least not for the question you're asking. You have to allow the data to tell the story & not impose upon it something other than what it can statistically support.

[@4bigwheels09]

Doing a ladder test/ocw with 3 shot groups is a fast track to eliminate the noise. If you’re measuring powder weight accurately then simply looking at extreme spreads of the data will tell you enough about powder charge to eliminate charge weights of a load. Since ES is a prediction of SD we can simply look at our ES to tell us where SD will be bad and eliminate them as a potential node. 3 shot groups provide a 59% confirmation of 20 shot groups. 5 shot groups 74% and 10 shot groups 89%. So 3 shot groups are enough to say with 100% accuracy a charge weight will be bad and 59% confidence they will be good. Once that data is collected it’s time to Increase our firings of a 59% confirmed charge weight. You do this by increasing to 5, 10 or 20 shot groups. This time being able to analyze the data with more scrutiny. If ES and SD are where you’d like them to be then it’s time to do the depth test. The mistake people make is taking 3 shot groups of accuracy and saying thats a node. You don’t use 3 shot groups to confirm a node, you use it to eliminate where a node isn’t. Hope that helps.

[@rotasaustralis]

@@4bigwheels09 I see what you're getting at. The problem with that assumption is that it supposes that all the data represents what should be happening at a particular charge weight over the three or 5 shots. The same issue applies to reading group ES. The 1st erroneous assumption is that any significant deviation is due solely to the charge weight applied without any other supporting data. The 2nd error is the fallacious logic that a significant deviation represents the ongoing characteristic of that charge weight. In both cases of velocity & group ES, the assumption should be that the rifle is just firing one shot after another in a continuous series & not divided into blocks of small samples. One large deviation in 5, 10 or 20 shots does not mean much without the remainder of the data. This is the reason why low sample numbers are misleading because we never get to see the real data trend. Low sample numbers hide the real trend & cause the shooter to infer a far greater emphasis on one or two data points well before a realistic data trend is evident. For example, one significant velocity deviation in 3 or 5 looks far worse than that same velocity deviation in 20 whereby, the SD of the 20 shot group show a very consistent trend with the one significant deviation standing out as an anomaly rather than a defining data point. The same situation applies to group ES. One significant deviation stands out amongst 3 or 5 shots but, 20 shots may have revealed 19 shots in one inch with that large deviation at 2 inches. What that tells me is that the shot at 2" was an anomaly & the rest support the overall effect on the target. It's not only possible that a very good "Node" could be discarded but quite probable. I don't know when shooters are going to understand that statistical principals cannot be shortcut & achieve anything meaningful. Thorough statistical testing is very reliable only when used correctly. When shortcuts are used, it is no longer statistics & cannot reliably be used as an extrapolation method.

[@elmerfudd7674]

Meanwhile I am actually out hunting something. Paper punchers are concrete/asphalt dwellers.

[@scorch101]

Thank you, thank you, thank you. I am sure with this comment you will win KZbin most gracious, helpful and knowledgeable comment. You sir are truly a man among men, worthy of all the praise you deserve. Even I, a lowly resident of Commiefornia, with few, but still some opportunities to seek four legged prey successfully is surely in awe of your stalking prowess. A true king of the beasts seeking to make mankind to rise in your image.

[@elmerfudd7674]

Uh oh. Triggered !! Momma always told us that sometimes the truth hurts. You seem hurt.@@scorch101

[@scorch101]

Not at all, just acknowledging your obvious supremacy.@@elmerfudd7674

[@58harwood]

This guy is absolutely clueless!

[@scorch101]

Always great to hear from the wonderful helpful people that comment on the internet. I think your advice was invaluable and helps all of us be a better person. You are a true gift to humanity.

[@lmbear]

What a waste of time. Hopefully no one buys your bs. A lot of poor info in your video. OCW means work up loads and find Optimum Charge Weight. Your way is ridiculous. When I see someone posting a charge weight of 41.9, as an example and then going up .2 of a grain, you are wasting components and your time. You should see significant nodes by increasing charge weights by 1/2 grain at a time. Start at 42 grains instead of 41.9. You are doing no one favors here. Shoot groups of 5 shots each and let the group dispersion tell you what you need to know. You don't even need a chronograph to work up an excellent load. After all, you are find the "Optimum charge weight". Groups will tell you that. The proof is always on the target, unless you can't shoot to save your life. This may be the case here???

[@scorch101]

Such a nice reply from such a courteous person, thank you so much for being alive. I am sure all your friends cherish your acquaintance.

[@lelandgaunt7130]

It's not 1970 any more numbnuts. We use chronographs these days and not your 50s alien movie antenna ones your grandfather used to rely on. Do it your way then, no one is telling you to do it this way. I for one use 3 methods. This, the 5 shot group and then 20 shots at 1200yds. If they all land on the same place, I know it's a good load. Usually between 17-25fps ES is what I end up with. There's is no sure way to do this or a real proven method. Anyone that's shot enough at far distances will tell you that. All anyone can do is get close enough and guess what? Too many variables and too many things figure into what the outcome will be. You are going to "waste" components like it or not. If you're not ready to accept that, pick a different hobby.