RE: OCW method. How are the first 3 powder weights determined?
Before the ladder test, I'd just grab the book and select the highest velocity load (I'm a velocity hawg) that seemed reasonable, back off a few percent and load 5 and go to shootin.
With the ladder test I did on the 375 I found a "node" hunted and pecked around it to get the hunting load I was going to use. The 375 was a bad one to judge things as it's maximum range is 300 yds and about anything stuck in it shoots the same.
With my LRH rifle, 338 Win, I haven't done a latter test or any other 'test' whatever. Got to the 75gr of RL 22 and the Sierra 250 GameKing and Wildcat RBBTs. Needless to say I have shot at a bunch of Sierras and 100 WCs (have gone through 3 pounds of power. Not all was accuracy tuning. Much was recoil reduction, ya know, change the stock, test results. I have it where I can shoot many prone rounds with out any adverse bodily harm.
However, all I have is a rifle I can comfortably shoot on the "tight rope" mentioned above.
So what I'm gonna do is run the ladder test, then instead of huntin' and pecking around a node, I'll do the OCW process.
I'll keep copius notes and hope that I can learn enough to be able to be more conversant on the subject. But mainly get to the point where I load a 100 cartridges and don't reload any more until I shoot 100 elk [img]/ubbthreads/images/graemlins/smirk.gif[/img]
I may be the slowest guy on the mountain . . . . but . . . . I'm on the mountain!
grit, that's pretty much it. Both tests are essentially seeking the same data. But the OCW method refines that data to a level that leaves a lot less doubt than a ladder test.
Now, if you were to shoot three ladder tests all in succession, that would make the results more cogent. If the same cluster or clusters formed in each string, there would be little doubt as to the location of the individual accuracy node(s). The problem here is that most folks use graduations which are too small, and end up shooting twenty shots in one string. That may be fine on some rifles, but on others--especially sporter weight barrels--heat issues will often spoil the results.
Roy, there are instructions at my webpage (and the info there is free to the world, I don't profit from this--I don't even have advertising on my site) which describe how to choose the powder charges to test. If you're using a Hodgdon powder, get hold of their data (actually, now that I think of it, Hodgdon's data is free at www.hodgdon.com )... Use Hodgdon's max load and back off 7 percent for a fouler/sighter, then move up about 1 percent and fire another (6 percent under max) then move up again and fire one more shot at 5 percent under max, then begin at 4 percent under max shooting three each in round robin fashion at each of 5 or 6 different target squares. Don't be tempted to shoot too many graduations. .2 grain increments are way too small for the .338WM. Use at least .5 grain increments. You should even be able to see good results with .6 grain increments. If the charge weight increments are too small, the barrel may heat and/or foul too soon for you to be able to see where the accuracy nodes actually are.
If you're using another brand of powder, such as Alliant or IMR (now owned by Hodgdon), do much the same thing as mentioned above. Go with the powder maker's max and back down about 7 percent and shoot three graduated sighter/foulers, then begin the OCW test. Powder companies tend to have the most useful load data, I've noticed. Bullet makers aren't so great, although Nosler's "most accurate powder tested" is generally a good place to start.
You are correct this is a healthy debate about the merits of the two techniques. I can sum it up like this: OCW is all about getting MOA groups under ideal conditions (Look at Dans website and standards for OCW) while a true ladder is about getting extreme accuracy which is well below the OCW MOA standard. Dan might disagree but that is OK (nothing personal, will buy him a beer and still argue the merits), every one else figure out which way you want to go.
If I only had a factory gun and only a 100 yard range then maybe OCW would be viable. However, this is a LR hunting board and it should be safe to assume that we are talking about substantially longer than 100 yards and that most people will have access to longer ranges within an hour or two to do serious testing before taking a gun hunting. I have to drive an hour to test at 300-600 yds so I do all my preliminary testing and zeroing at a local 100 yard range.
Good planning figure is that if you are getting .5 MOA at 100, then your distance groups will be 2x that .5MOA. In other words you will have a 10" group at 1000. That is why for LR hunting (past 500 for sure) you want to be in the .2-.3 MOA range as a minimum.
I believe that when Dan says that OCW is simply 3x the ladder, that is fundamently incorrect. The only thing he is doing that resembles a ladder is firing increasing powder charges.
1. The accuracy standards are different. the standard for OCW is MOA (based on Dans website and previous postings). Ladder goal is sub MOA.
2. OCW you do not use a chrono, has no purpose. True Ladder it is key to defining a sweet spot for the barrel on both accuracy and MV. You need both. Normally they coincide but not always. If you know where the MV jumps are they normally coincide with the next jump in pressure so you can avoid dropping off the ragged line of pressue. Using a chrono allows you to plot and define all the jumps. You will find that your shots will jump 20 fps each shot and suddenly 3-4 will be within 10-15 fps of extreme spread and the next shot jumps 20 fps again. You have probably found a tuning node or sweet spot for that barrel. I can tune in the middle of that node and with OCW you have no idea where it is other than it seems to group here.
I think that if all you want is MOA, then OCW will give you that, which maybe makes it OK for factory barrels. However, as I stated earlier I can take almost any components and get MOA with a match barrel. If you have a $500 match grade barrel and chamber and you want .2-3 MOA accuracy then OCW and Dans website reloading techniques are left way behind.
For example, He states that reaming flashholes for uniformity is waste of time and subject to dispute within the BR community. Got to differ as I shoot LR BR for the past 5 yrs, ranked nationally and most of us do our reloading similar, but we are learning more all the time how to refine and make our loads more uniform and everyone starts with flasholes as the ABCs of reloading. Never heard of any BR competitor not doing it As most flasholes are "punched" it leaves a lip sticking up inside the case and sometimes the lip rolls over the hole and sometimes it is not even open all the way.
He does not believe in custom dies. A die that matches your chamber minimally resizes the case preventing overworking the brass and work hardening the necks. Work hardened necks will increase neck tension on the round significantly. Short range BR rounds normally use .001-.002 neck tension while LR BR rounds are normally .0015-.003 and some have found that up to .004-.005 work for flat base bullets. Standard dies will give you about .010 neck tension. Uniform neck tension is the last element to hitting the tightest groups. I am sure that he is not aware that if you neck size cases and let them sit for say two weeks you will get about an extra .001-.0015 spring back, ie loss of tension. .001 variance in neck tension will open a group up. This has been confirmed by top shooters using custom pin guages to accurately measure the exact diameter of the necks and arbor presses with dial indicators on top to measure actual seating force. You can measure neck tension and the seating force exactly now with the right equip.
He also does not believe that seating depth plays a role in loading, only as long as all seated the same length on the ogive. He is correct as long as your standard is only MOA.
However to get to that sub 1/4 MOA level, .005 seating depth change can open or close a group as much as 3/4 MOA. Seen it and done it too many times to say otherwise.
If you are shooting a ladder for a magazine gun then start at max OAL, if you are testing for a gun that will be singly loaded then start the ladder about .030 in the lands for custom VLDs and Sierras and Hornadys just touching. That will be your max pressue points also. As you back off pressure decreases. Most VLDs like to be seating anywhere from .010-.030 in lands, while most Sierras just touching or off as much as .040.
"OCW is all about getting MOA groups under ideal conditions...
You haven't read the text of my website if that's what you actually believe. The MOA standard is for the low, normal, and high charged shots. Here is what I'm talking about:
The above is a sub MOA group with THREE DIFFERENT powder charges.
And at 300 yards:
This group, consisting of the low, normal, and high shots at 300 yards is actually about 1/2 MOA.
When you go to all 43.6 grains, groups at 300 yards are unbelievably tight. I've actually printed dozens of 1/3 MOA five shot groups at that range when conditions allowed--using OCW loads, first identified at 100 yards.
"Dan might disagree but that is OK (nothing personal, will buy him a beer and still argue the merits), every one else figure out which way you want to go."
I will take the beer! [img]/ubbthreads/images/graemlins/laugh.gif[/img]
"If I only had a factory gun and only a 100 yard range then maybe OCW would be viable."
This was the first 1000+ yard group fired with a recently developed OCW load developed at 100 yards--from a factory barreled Savage. The brass was not match prepped in any way, and the load had not yet been tuned with seating depth adjustments.
"1. The accuracy standards are different. the standard for OCW is MOA (based on Dans website and previous postings). Ladder goal is sub MOA." Nowhere on my site do I suggest that one should stop accuracy testing when MOA is reached. Again, you're reading only bits and pieces of the text, and jumping to conclusions. The MOA standard I mention is for the low, normal, and high charged shots--all together. If you load only the normal shots on an OCW recipe, it tends to look like this:
Again, from a factory barrel at 315 yards. Bring on the customs, by the way. [img]/ubbthreads/images/graemlins/wink.gif[/img]
"2. OCW you do not use a chrono, has no purpose." That is true. You're 1 for 3 now. [img]/ubbthreads/images/graemlins/tongue.gif[/img]
"I think that if all you want is MOA, then OCW will give you that, which maybe makes it OK for factory barrels. However, as I stated earlier I can take almost any components and get MOA with a match barrel."
Here's the first testing at 1062 yards of an OCW load, developed at 100 yards for a Douglas 8 twist .243 win. The brass was regular Winchester stuff, just drawn from the bag--no match prepping, no weighing. The two high shots are likely odd weight cases, but as you can see, the group is still MOA at extreme range. Subsequent groups have been even better...
"For example, He states that reaming flashholes for uniformity is waste of time and subject to dispute within the BR community."
You're partially right about this. 1.5 for 4 [img]/ubbthreads/images/graemlins/smile.gif[/img] ... I've never seen the need to deburr flash hole on good brass. I just went through 200 Lapua 6.5 x 55 cases the other day, checking their overall condition, etc. I noted that there was not even a hint of a burr in any of those flash holes. Probably they are drilled. In any event, if you're looking for BR type accuracy from Winchester or Remington brass and you'd like to deburr flash holes, you'll get no argument from me--other than to question your choice in brass.
"He also does not believe that seating depth plays a role in loading, only as long as all seated the same length on the ogive."
WTF? [img]/ubbthreads/images/graemlins/confused.gif[/img] If you'll read elsewhere on my site, you'll see that I certainly do believe setting the proper seating depth is important. Most guys--yeah, even the BR gurus--get this bass-ackwards. You want to adjust seating depth after you have identified the OCW. While it is true that any reasonable, uniform seating depth will do for OCW testing, you don't want to just leave things at that--unless the group sizes are already satisfying you--in which case you should save the components and the time and the barrel wear and just go hunting. [img]/ubbthreads/images/graemlins/smile.gif[/img]
I actually advocate what I call "depth tuning" which, after the OCW has been identified, will allow you to make the load even more accurate. By the way, the only load actually depth tuned in the target photo above is the 180 gr Nosler BT/Varget load. On the 1000+ yard targets shown, the loads had not even been depth tuned yet.
I'll offer my opinions. Bear in mind, I'm a novice who just shot his first load development test of any kind.
1. The ladder test provided me with an accurate load. Even without a chrony, this time.
2. I shot 17 shots to find it, and 21 shots to test it. That's pretty productive. I believe one of the benefits of the ladder is it points out accuracy nodes with a minimum of shooting. This is not something I would give up.
3. If I was to alter the ladder test, I would simply multiply it by three. This would help remove questions about margin for error. It would also show grouping. Basically combining first test, and accuracy test as I performed them. I would only do this if a single ladder test didn't provide results I was happy with.
Thats all the debate I have in me [img]/ubbthreads/images/graemlins/wink.gif[/img]
Wait, wait, I'll buy the beer and bring six guns.