OCW...the new buzz word?why?

[JByrd]

I keep hearin all this talk about ocw this and ocw that. all the test targets ive seen haven't really been that definitive at all. to me a ladder test is just so much more clear. move to 400 +/- in early morning or late afternoon calm conditions and it clearly gives you node clusters in 15 rds max,then refine your oal to get tight short. then people say well not all people have access to a 400 yd range to which I ask........ why are you loading for a long range/precision rifle and on tactical/precision rifle forum????

just an observation... I had to throw it out there. to each his or her own I guess

EDIT, post discussion/study

I have finally gotten a chance to really study the OCW method and how to interpret results. Ocw IS a short range ladder test. there is a little mention of windage shifts and a few targets have that but the majority of them are clusters of verticle shift with a lil windage shift and your looking for the gun to get flat as usual.Dan is a real nice guy with a good option for development that should work with careful interpretation. I think the interpertation part is the Achilles heel of the system.I am going to start using the round robin procedure from his method on my 400-600 ladders and fire 2 shots per charge vs. 1 so its a lil more thorough and puts heating into play more or at least see what the effect is this time. I think this prob is the best bet for the guys that don't have access to shoot distance, but again I still stand by my points
the nodes are much easier to clearly see at distance
and its good to see exactly what the bullets ARE going to do at the distance the shooter plans to engage the majority of targets at.

I hate to burn the extra powder/proj but I will try to post pics of both methods when I work the rebarrel up.

 

[oldfatguy]

Simple answer. OCW works very well. Ladder testing also works, but requires greater ranges then OCW.

OFG

 

[rduckwor]

I think OCW is a bit easier for most of us to use and interpret. It is typically done on a 100 yard range and most have easy access to that distance.

 

[Infinity]

http://www.snipershide.com/shooting/snipers-hide-reloading/210435-ocw-interpretation-help.html

...explains the process pretty well.

 

[trailrider121]

Lately, I do a ladder test at 300 yards min. Shoot it round robin to be fair. Find a good node area, and do a semi OCW method working around that node area at 300 yards again. Once I find OCW, I then adjust col to find tune. 100 yard ocw works, and must ranges are close. Some have to drive an hour or so to long distance range, and to do load testing would be a pain.

 

[Desert Fox]

For me both is a total waste of barrel life, powder and bullet. I usually found my load with as little as 15 to 20 rounds. Now this is just my opinion. Take it for what it's worth.

 

[ChrisGarrett]

For me both is a total waste of barrel life, powder and bullet. I usually found my load with as little as 15 to 20 rounds. Now this is just my opinion. Take it for what it's worth.

Yeah, I'm kind of that way too. Select a bullet and powder, play with a few charge weights and shoot a few groups. I consider it practice, even if a particular charge weight doesn't group ideally.

Chris

 

[Dan Newberry]

I'm sure my system isn't for everyone--and there are many ways to "skin this cat"... so I would never dissuade someone from doing what works for them.

With the right approach, you can find a really great load in as few as 18 shots using the OCW method; a load which will be very resistant to throwing flyers. Sometimes the flyers are shooter induced (guilty as charged )... and sometimes it's just a non-optimal load that seemed good at first, but was not deep enough into a good node to resist pressure changes that spoil accuracy.

Dan

 

[Sugarbug]

I keep hearin all this talk about ocw this and ocw that. all the test targets ive seen haven't really been that definitive at all. to me a ladder test is just so much more clear. move to 400 +/- in early morning or late afternoon calm conditions and it clearly gives you node clusters in 15 rds max,then refine your oal to get tight short. then people say well not all people have access to a 400 yd range to which I ask........ why are you loading for a long range/precision rifle and on tactical/precision rifle forum????

just an observation... I had to throw it out there. to each his or her own I guess

Easy there, tiger. Why not "to each his own?" I, for one, am glad I have an good option to use at the 100y range 10 minutes away than only an option that I have to drive two hours to use.

 

[roggom]

I have used other methods, and sure have found nodes rather quick, but that is not always the case. Dan's system allows for a consistent and methodical approach to finding accuracy nodes. Since the test can be done at 100y, I can use a local indoor range. No wind, and less variables to affect my testing (parallax, DA, bipod loading, NPA). Works for me.

 

[Supersubes]

In my experience most people spend way too much time load developing. I am also a simple reloader and generally have it worked out quickly, but not as quick as when I use the OCW method. I agree with the OP that at distance, the results are clearer. I do it a little beyond 500, on a single bull, with sharpy colored bullets. Works for me.

 

[FN in MT]

Why OCW? Because it works.

You like the ladder...and it works for You. Fine, You are GTG.

 

[JByrd]

Easy there, tiger. Why not "to each his own?" I, for one, am glad I have an good option to use at the 100y range 10 minutes away than only an option that I have to drive two hours to use.

Re read the last sentence of my post

 

[Sugarbug]

Re read the last sentence of my post

It wasn't sexist enough.

 

[bigedp51]

Erik Cortina of Lapua Team USA explains OCW very well at the link below.

Long range load development at 100 yards.

 

[JByrd]

Even on his test targest hes talkin about comparing groups before and after the 2 good center groups
Top row previous group is clustered high and group after the good one is clustered low. He speaks about the high low

Bottom row. Center group best again but both previous and group after have as much vert. Stringing as the top row . They are not clustered one hig and one low they are each strung high AND low. This is why i say its hard to see a clear winner. In reality it is just your high low nodes that would show up clearly at distance but it took 18 rds and your not even in the second stage double check of refinement.

Dont get me wrong i still shoot 5 shot groups when tightening the gun up short. But my main initial concern is whats the gun goona do at 600 where 90% of comp shots are going to be taken. I want to start refineing from the winners there.

Im not sayin its wrong or right im just sayin before everybody jumps ship on ladder test, i would do some serious thinkin about it. If your gonna do most of you shooting between 100 and 300 i think ocw is your test. If your going to shoot mostly at 600 plus im still not convinced.im not closing my mind to it,im just not convinced yet. Lets say im kinda hype skeptic thats all. In 5 years i may be on here askin why the heck people are doin ladders still,but so far i doubt it.

 

[shoot4fun]

My 223 bolt gun OCW has proven itself thru temp and other environmental extremes and distances out to 1000 yards. I have tried many methods over my 40 years at the reloading bench and OCW has worked best for me.
Don't knock it until you try it.

 

[Rhyno]

The second row on Eriks target shows clearly why the OCW works.

Remember your not looking at the group, or the stringing your looking at how the center of the groups relate to each other.

All three in the second row had very similar center of group relationship.

After that you mess with bullet seating to fine tune the load.

 

[Tripwire]

I'm sure my system isn't for everyone--and there are many ways to "skin this cat"... so I would never dissuade someone from doing what works for them.

With the right approach, you can find a really great load in as few as 18 shots using the OCW method; a load which will be very resistant to throwing flyers. Sometimes the flyers are shooter induced (guilty as charged )... and sometimes it's just a non-optimal load that seemed good at first, but was not deep enough into a good node to resist pressure changes that spoil accuracy.

Dan

Don't fret it Dan, some of these guys would bitch if they got hung with a new rope.

We need to do lunch again soon......

 

[JByrd]

I got a gun comin back from a rebarrel fairly soon. Im tempted to work it up both ways and post results here and let the man hisself interpert the test stages as i go. And then work the ladder and see if i end up with the same charge or not. Then test them head to head on my 1025 yd target at early morn or dusk and post results. Like i said im not closeing my mind to it, its hard to talk myself into developing a longrange load short. Im gonna have to ladder the new barrel anyway and its a win win for me so whatever.

And as far as you are concerned tripwire,im not bitching, im questioning and compareing. Dont "eat" too much , and enjoy your dinner

 

[Dan Newberry]

procovert, that plan sounds interesting. I'm human, though, and certainly fallible... but to date, I've not missed a good long range load when I saw it staring back at me from the 100 yard target.

Tweaking the load with seating depth adjustments at 300 and beyond isn't a bad idea. I have found another "work around" for that, though, which can still be done at 100 yards. If you work with the seating depth to "steer" the cold, clean bore shot into the group, this seating depth (whatever it ends up being) is the preferable depth for the longer ranges as well. An added bonus is that you don't have to pre-foul your bore before a hunting trip or a match.

Tripwire... I've got some idle time this week. Say the word, my treat this time... lemme know.

Dan

 

[steve123]

I keep hearin all this talk about ocw this and ocw that. all the test targets ive seen haven't really been that definitive at all. to me a ladder test is just so much more clear. move to 400 +/- in early morning or late afternoon calm conditions and it clearly gives you node clusters in 15 rds max,then refine your oal to get tight short. then people say well not all people have access to a 400 yd range to which I ask........ why are you loading for a long range/precision rifle and on tactical/precision rifle forum????

just an observation... I had to throw it out there. to each his or her own I guess

Seems like Dan is a smart guy that is also humble, which is very nice to see! Hey, anybody remember the solid projectile geniuses arguing back and forth on the beyond 1000Y forum as to why their design was superior??? Interesting to read but not much came of it.

OK, so both a ladder at say 400Y and the OCW method at 100Y should correlate at the same powder weights right?... by showing the same nodes, a high node and a low node. Procovert45 and Dan, I have a new barrel ready and waiting at the gunsmith. I wouldn't mind trying both methods as a experiment to compare. To be honest I've only done ladders up to this point but am open to trying the OCW.

 

[Dan Newberry]

In my own experience, it's hard to always know whether the lateral shift in a longer range ladder is due to wind (which many folks simply disregard), or due to an actual POI shift brought by the barrel itself. At 100 yards in no wind, you still see POI shifts and flyers going due right, and due left... so we know that non-optimal charge weights can shift laterally when wind is not to blame.

Depending on the bullet and the velocity, you can see around a full MOA of shift even in light winds at 300 yards. Then the question becomes: Did an unnoticed puff of 3 or 4 mph wind move that shot 4 inches left, or is that simply where the barrel is sending that bullet at that particular powder charge?

Non-optimal powder charge areas (particularly "scatter nodes" as I call them) can move shots here, there, and yonder with the SAME powder charge. A scatter node charge weight will actually put 1 or even 2 shots out of 3 right on the same POI that the preceding (or proceeding) powder charge does. This can really mislead you if you're only looking at one charge weight per shot. Shooting three shots at each charge level should reveal the scatter node's location. You can read more about the scatter node at the OCW webpage (linked in signature line)... click OCW versus Ladder Test.

Dan

 

[Rprecision]

I have found OCW to be a useful tool in load development. If your main complaint is the range, then shoot it at 400? It will work at 400 just as it will at 100 the only problem is the conditions have a greater effect.

Dan has put alot of his hard work out there for others to use for free, not something you see alot of these days

Hey besides if you dont like it dont use it. Its not like you spent any money on learning to use it.

 

[308sako]

The second row on Eriks target shows clearly why the OCW works.

Remember your not looking at the group, or the stringing your looking at how the center of the groups relate to each other.

All three in the second row had very similar center of group relationship.

After that you mess with bullet seating to fine tune the load.

"your looking at how the center of the groups relate to each other."

This is exactly what the OCW will show you. Do not adjust your sights as the impact points move around the paper, that's your barrel finding it's happy place.

I am an OCW convert because it works better than any other method for ultimate precision I have found.

Ultimately, do what works for you.

 

[Supersubes]

Dan, i understand what you're saying about not being sure of lateral deviations.

When I look through my long range OCW targets, which encompass a few calibers, the wind factor doesn't seem to add
much. In fact the groups are fairly round for the most part. I am generally very pleased with just how small the groups are as a whole. The vertical however is very easy to resolve. Admittedly I'm shooting high BC bullets (usually 6.5's) out of full custom rifles.

 

[stanley52]

Tweaking the load with seating depth adjustments at 300 and beyond isn't a bad idea. I have found another "work around" for that, though, which can still be done at 100 yards. If you work with the seating depth to "steer" the cold, clean bore shot into the group, this seating depth (whatever it ends up being) is the preferable depth for the longer ranges as well.

Can you explain this further? Is this to say if you tweak your seating depth on a clean/cold bore, it will have the same POI as a fouled bore?

 

[steve123]

In my own experience, it's hard to always know whether the lateral shift in a longer range ladder is due to wind (which many folks simply disregard), or due to an actual POI shift brought by the barrel itself. At 100 yards in no wind, you still see POI shifts and flyers going due right, and due left... so we know that non-optimal charge weights can shift laterally when wind is not to blame.

Depending on the bullet and the velocity, you can see around a full MOA of shift even in light winds at 300 yards. Then the question becomes: Did an unnoticed puff of 3 or 4 mph wind move that shot 4 inches left, or is that simply where the barrel is sending that bullet at that particular powder charge?

Non-optimal powder charge areas (particularly "scatter nodes" as I call them) can move shots here, there, and yonder with the SAME powder charge. A scatter node charge weight will actually put 1 or even 2 shots out of 3 right on the same POI that the preceding (or proceeding) powder charge does. This can really mislead you if you're only looking at one charge weight per shot. Shooting three shots at each charge level should reveal the scatter node's location. You can read more about the scatter node at the OCW webpage (linked in signature line)... click OCW versus Ladder Test.

Dan

I went over to your site and read up on the OCW so I'll try it here in a few weeks.

When I do any ladder I go out in the morning before the wind kicks up and with this last barrel in 6x47L I shot two rounds each charge to try to eliminate uncertainty, which worked out. I noticed the horizontal tightened up when in the nodes as well. Then I finished seating depth adjustment at 200Y. The very last group had 4 shots touching at .2" but ended up with a 1/2" group on the 5th. IIRC I was done with the load development in 50 to 60 rounds all together.

This time around I'm only interested in the high node so I think I'll do a ladder in .1 grain increments and also do it round robin for the heck of it.

 

[SporterII]

I read about the OCW test. My target showed groups tightening and going away. I could see three charge weights come together then go away. Come back again and I take the center high end group. Good results at distance now and I still do not know how to properly read this test. My 'version', best I could do, workin so far.

 

[Dan Newberry]

Can you explain this further? Is this to say if you tweak your seating depth on a clean/cold bore, it will have the same POI as a fouled bore?

Yes, I generally do this with all of the loads I use in the various rifles I shoot. I have found that some rifle chamberings are a bit more conducive to accomplishing the cold, clean bore shot tightening than others. Bullets which are matched well to the twist seem to work well when attempting this.

In short--yes, you can by adjusting the seating depth find a place where the CCB shot is into--or very nearly into the following group.

Here is a recent target... I haven't decided whether to tinker with the OAL on this load any further. The CCB (left group) is about 3/8" off to the left. This is repeatable... and the following 3 shots are in the same place, less than 1/2 MOA to the right.



Here are some targets from past tinkering...







here is the test target before shortening the OAL by .005"...


And again, if you adjust you load in this way, it seems that accuracy is phenomenal at the longer ranges (in most cases).

Dan

 

[bruddah]

Great info!

 

[usmc02xx]

i like the ocw becuase i can find a node for 100 that has no impact shift through a range of weight. then i settle in middle and i can throw powder without weighing every single one. my 243 was a great example. the load i had stayed tight and same POI for almost a full grain before falling apart. i load to the middle of that and i can throw powder at will without breaking ou the scales except to verify first throw. my dumper will be +/- .3 gn so im in the house. I also use to fine tune my longer stuff. its very interesting to see i tcomeout of the node and see poi shifts and groups sizes grow. nothing is worse than having a great grouping load and the temo go up 20 degrees and it fall apart. a good ocw will keep that kind of thing to a minimum.

 

[steve123]

Seems like Dan is a smart guy that is also humble, which is very nice to see! Hey, anybody remember the solid projectile geniuses arguing back and forth on the beyond 1000Y forum as to why their design was superior??? Interesting to read but not much came of it.

OK, so both a ladder at say 400Y and the OCW method at 100Y should correlate at the same powder weights right?... by showing the same nodes, a high node and a low node. Procovert45 and Dan, I have a new barrel ready and waiting at the gunsmith. I wouldn't mind trying both methods as a experiment to compare. To be honest I've only done ladders up to this point but am open to trying the OCW.

Yesterday I went out and broke in my brand new Krieger 30"-8 twist barrel chambered in 6x47L. I shot 14 rounds through it with a few thorough cleanings, one after 2 rounds and the other cleaning after the 14th round.

First off, I'd like to thank Dan Newberry and Audette for thinking outside the box and creating a way to quickly find a accuracy node!

This morning I shot my first OCW.

The powder I selected for this test is H-4831SC, lit by CCI450 primers and the bullet used is Bergers 105 grain Hybrid. The rifle is a MAK tube gun with a trued-screwed and glued M700 with PTG bolt. I used a Farley joystick front rest and a Edgewood rear bag.

Winds were in my face from 2-6 mph est, switching back and forth a little and rising towards the end of test. I let the barrel cool a couple minutes after each 3 shots with two 10 minute breaks for the cease fire at the range.

The low right bull was my first 3 shots to warm the barrel and get a left to right zero, this included the CCB. I adjusted the scope over .1 mil left for the test. The group directly above it was the very last group shot by my friend Christopher after the OCW was finished.

Shooter ballistic program gave a .1 mil windage variance - left /right- between 10 oclock and 2 oclock at 6mph. Unfortunately I spaced out putting up a wind flag so I have no idea exactly what the wind was doing from shot to shot. I clearly see where the scatter node is at #7/ 43.4 grains but grouping seems to come back at #8 43.7 grains. I might be able to stuff 44 grains in a case if I got a drop tube but I stopped at 43.7 and it was very compressed.

Please help me interpret the results from the pic below. Which powder charge would you consider optimum??

Chronogragh didn't pick up a few shots so I estimated velocity here and there.

Thanks

At my earliest convenience, when I find a morning that is calm for the most part, I'll do a ladder test at 400 yards. But I'll shoot it round robin and shoot it in .1 grain increments because I haven't shot a ladder that way before.

 

[Dan Newberry]

I would say the scatter node at 43.7 points back to an OCW of 43.0 grains. Then there's a node under that level at 41.7 grains, if you want to try that.

There should be another scatter node at 42.4 grains. The fact that 42.5 shot tight the second time around is interesting, but I question whether that's going to be a repeatably accurate charge for you.

Good luck with the longer range testing.

Dan

 

[steve123]

I would say the scatter node at 43.7 points back to an OCW of 43.0 grains. Then there's a node under that level at 41.7 grains, if you want to try that.

There should be another scatter node at 42.4 grains. The fact that 42.5 shot tight the second time around is interesting, but I question whether that's going to be a repeatably accurate charge for you.

Good luck with the longer range testing.

Dan

Thanks for your advice Dan.

The results are a little confusing to me.

It looks like #2/41.9gr is a low node because the group before and after are at the same POI and they are all in the .2's but two of the #4/42.5gr groups are small and same POI, with that one flyer off to the left on the 3rd #4 group, all of which should be in the scatter node. I was surprised the other two shots hit the CCB also.

Velocity wise I'm more interested in #6/43.1gr/3110fps but the groups seem to be growing in size at the higher velocity's. What to do???

 

[Dan Newberry]

Steve, I see what you're saying about the lower node. It's just that obvious scatter node that seems to anchor the results at other points as well. I know the lower scatter node isn't even showing up so well, but with very accurate rifles, good bullets and powder selections (and great shooters too), scatter nodes can be subtle. It looks like the evidence is there; that the scatter node is somewhere around 42.4 grains... but I guess we'll have to see.

You're right, as the pressure increases the slight differences in case construction, as well as the nuances in bolt lug fit, action integrity, etc. get amplified, and accuracy falls off before the next OCW node is reached.

See how 41.7 grains shoots at long range, and of course test 43.0 grains to see what happens.

Dan

 

[RobertB]

I have always used OCW with no Chronograph, once I find the load I like (doesn't take a lot of shots) I shoot a group on my 600yd paper backer and decide whether its good enough or not. If it is I'm GTG, if not tune a little more. SO far, every load that looked good at 100 or 200 that I liked worked very well at 600&1000 yds.

Latter test work well too. Just because less people use it doenst mean it doesn't work as well. Usually people do latter tests at the distance they will be shooting, 600 or 1000 yds.
OCW can be done easier for most people.


Good luck

 

[Desert Fox]

I just can't wrap my brain on this OCW/Ladder thingy. I always thought that if your stick is put together, using the best component by a very competent smith, you shouldn't have problem finding load. When developing load for my rifle, I always start by establishing velocity parameter. Then I will choose the most common proven powder that bullet manufacturer recommend for that particular cartridge and load 20 rounds total in 4 sets of 5 in half a grain increment for 308 size cartridge and 3/4 to 1 grain on large magnum caliber. I'll chronograph the load and watch for velocity. If the starting load is too slow, I will skip it and proceed with the next one and so on and so forth until I arrive at my velocity parameter. Once I got there, I normally won't proceed no farther.

Here's one example. I wanted to try 178 A-Max for my 308. I wanted the velocity to be around 2600 fps. I have two proven powder on hand that I know is a 308 performer ( Varget and BLC-2). I loaded using Varget starting at 39.5, 40, 40.5, and 41 grain. Went to range and chronograph the load.

Here's my result:



As you can see, any of those load shoots tight and at 40 grain, the velocity was already over the 2600 fps parameter. I forgot to write the velocity I'm getting from the 40.5 and 41 but I believe it was around 2635 and 2650 respectively. So with this result, I decided that 41 grain will be the ticket.

I load another batch of prepped Winchester brass on different lot and checked the consistency and of the 41 grain load. I shot 10 rounds and here's the result. As you can see the velocity went down but still above 2600 fps.

[/URL]

I use this load at our local 600/1000 yards championship of which I took 1st place. You can see how the load group at 600 yards. Mind you this was a night shoot and the target was illuminated by a 50 watt light bulb. I was just aiming at the center chest on the Zombie target. You can only kill a Zombie by shooting it in the head so I put my last round right between the eyes.

 

[Dan Newberry]

Desert Fox, great shooting... like I mentioned earlier, there's lots of ways to skin this cat.

If we weigh every charge precisely, with (as you mention) a good powder and bullet for the rifle at hand, we can make nearly any charge work well, as you've proven here without question. For instance, with IMR 4064 (very much like Varget) it is nearly impossible to find a powder charge within reason that won't group well from a well put together rifle.

But even then, there are charges that will be deeper into the accuracy groove, and therefore behave better and more consistently--especially in factory and well worn rifle barrels. None of that is to say that charges outside of that groove cannot perform exceptionally well if carefully weighed (which granted, most of us will do anyway if we're serious about accuracy)... it's simply to say that some powder charges are going to be more forgiving of rougher factory barrels, and .1 to .2 grain variances in the charge weight, and non-segregated brass cases, etc.

Dan

 

[Desert Fox]

Desert Fox, great shooting... like I mentioned earlier, there's lots of ways to skin this cat.

I guess so. Here's another one.

I already have a proven load for my 6.5-47 Lapua which I use at our local 1000 yards competition. Here's a 5 shot group at 110 yards.



Here's how that load grouped at 1000 yards that earned me 3rd place. I scored 246 I believe.



Out of the blue my wife decided to shoot with me at our next 1000 yard competition. The problem was, she doesn't have a rifle and i only have 1 month to get her to prepare. Mind you, she never shot in any competition, let alone a 1000 yard at that. So I decided to have her use my 6.5-47 for the shoot. In the main time, she need to practice.

I used up the last lot of powder I had and I'm on the new batch. As a precaution, I reduced my load from 41.3 to 40.5 and had my wife practiced with it. This was her result at 110 yards.





The weather forecast predicts a 100 degree temperature, the day of the match. And to be safe, i reduced the load further another half a grain to 40 without testing to see if it is a good load. I'm confident that my Gruning built rifles will shoot no matter what I feed it.

Turned out she can't make it to the match due to prior commitment so I ended using the rifle. I scored 247 out of possible 250 which again earned me 3rd place.

Here's the 25 shot group with the 40 grain grain load at 1K. The load barely clocked 2800 fps.

 

[Dan Newberry]

good stuff... great shooting.

 

[steve123]

Rommel, it might be that you don't have enough of a velocity spread in your 308 from 39.5 to 41 to get out of the barrels node since you stated you were already past 2600fps at 40 grains??? I'm guessing 60 fps difference between 39.5 and 41???

With my test I've got a full 200 fps spread from 41.6 to 43.7. Definitely going to swing in and out of some nodes with a large velocity spread like that.

Here where I live in northern AZ we can have our long range steel match in the morning in the winter well below freezing and be shooting a match in the afternoon in the summer above 100 degrees. In this match we engage steel from 200Y to 1080Y during a single stage so it's important to have a very consistent load with small vertical. The reason I use a ladder or OCW is to find a powder charge that is tolerant to temperature year around while still staying in that accuracy node. I use temp tolerant powders only but they still vary in velocity with temps some.

In most cases, once a node is identified, seating depth can be adjusted to tighten up groups. Also I've noticed that just because a load groups well at 100Y doesn't necessarily mean it's going to group the best at distance. In the past I've shot sub half minute groups that had horrible extreme spreads but I sure wouldn't be using those loads at a long range match.

Personally I'm looking for the best compromise. I want a load that is accurate "enough", tolerant to temp swings, with low enough pressures so I don't have to worry about a sticky bolt in the summer heat and that has reasonably low - "single digit" standard deviation. Perhaps this might be a good example... I went out this morning to try the ladder with those 105's but there was someone already there so I couldn't do it. The guy was shooting from the 600Y berm so I asked if I could shoot with him. I had a partial box of my old load that I decided to try for the heck of it. I put my MGM mini popper - (4" at the widest) down next to his steel, got out my rifle, shot and hit low on the popper, dialed up 3 clicks then put 4 shots into 1.2" near the center. That old standby ladder tested load just rocks! Won me a couple long range championships too.

Hey, congrats on your accomplishments there man!

 

[Desert Fox]

Don't know Steve. My 308 is a pig of a rifle. Nothing special, just a Remmy with 3 grove 12 twist Pac-Nor Supermatch MTU contour in AICS.

Tried this 168 grain Berger Vld... just pick a load out of the blue and it will do this. Maybe this is worth pursuing also.



Here's a 10 shot group with two different charge about a grain apart using the same bullet. I'm trying to duplicate the Federal gold Medal match 168 grain load using Nosler Comp bullet. I pulled one out...my fault.



My preferred long range load using 155 grain Lapua Scenar.



The bottom line is I always developed load this way and it always works for me. I guess like they said to each his own.

 

[Dan Newberry]

The Federal GMM is using IMR 4064 again. We're all but certain this is the case, especially with the Mk316 Mod 0 military long range load specking IMR 4064, and of course Federal is making that load.

Pulled down recent lots of 168 Federal GMM has 42.8 grains of IMR 4064. That charge would deviate a bit, depending on what brass you were using. In Winchester brass, it would end up being 43.2 or 43.3 grains most likely.

 

[steve123]

Yesterday I went out and broke in my brand new Krieger 30"-8 twist barrel chambered in 6x47L. I shot 14 rounds through it with a few thorough cleanings, one after 2 rounds and the other cleaning after the 14th round.

First off, I'd like to thank Dan Newberry and Audette for thinking outside the box and creating a way to quickly find a accuracy node!

This morning I shot my first OCW.

The powder I selected for this test is H-4831SC, lit by CCI450 primers and the bullet used is Bergers 105 grain Hybrid. The rifle is a MAK tube gun with a trued-screwed and glued M700 with PTG bolt. I used a Farley joystick front rest and a Edgewood rear bag.

Winds were in my face from 2-6 mph est, switching back and forth a little and rising towards the end of test. I let the barrel cool a couple minutes after each 3 shots with two 10 minute breaks for the cease fire at the range.

The low right bull was my first 3 shots to warm the barrel and get a left to right zero, this included the CCB. I adjusted the scope over .1 mil left for the test. The group directly above it was the very last group shot by my friend Christopher after the OCW was finished.

Shooter ballistic program gave a .1 mil windage variance - left /right- between 10 oclock and 2 oclock at 6mph. Unfortunately I spaced out putting up a wind flag so I have no idea exactly what the wind was doing from shot to shot. I clearly see where the scatter node is at #7/ 43.4 grains but grouping seems to come back at #8 43.7 grains. I might be able to stuff 44 grains in a case if I got a drop tube but I stopped at 43.7 and it was very compressed.

Please help me interpret the results from the pic below. Which powder charge would you consider optimum??

Chronogragh didn't pick up a few shots so I estimated velocity here and there.

Thanks

At my earliest convenience, when I find a morning that is calm for the most part, I'll do a ladder test at 400 yards. But I'll shoot it round robin and shoot it in .1 grain increments because I haven't shot a ladder that way before.

Today I did the 400 yard ladder test and was fortunate this morning because it was almost calm out.

The barrel had been cleaned after the OCW and had 8 shots through it including 3 shots to warm up the barrel for this test. The test took 1 hour 45 minutes to complete and I drove back and forth for every shot which took 4 minutes each trip. Yes this is a PITA but it gives a chance for the barrel to cool down a equal amount of time between shots.

Shots #1 and #2 hit farther right than I was expecting so to stay on the paper I adjusted the scope left .2 mil and continued through to #19 with that windage setting. As you can see #19 almost missed the paper because a small wind came up for that shot. I thought the wind would stay so for shots #20 through #24 I brought the scope back to the right .2 mil however the wind died back down so they are right of center.

Of all things the 3" wide Whidden sled came loose. I noticed it at shot #15 and tightened it but I think it had slid back and cocked on shot #8 because the rifle recoiled to the left on that shot.

I didn't take time to set up the chrono because I got a late start and wanted to try to get done before the wind came up.

Sorry, I had said I'd shoot this test round robin and forgot till almost the end of the test so they were shot from lightest to strongest powder charge.

Looks like two nodes, the low node around 42.3 grains and high node around 43.2 grains.

For reference the black bull is .75". Shots 14 through 18 measure .9" ctc.

Here are the results.

 

[Dan Newberry]

The accuracy nodes are typically 3% apart... with a node at 43 grains (or thereabout) the next lower one would be down around 41.7 to 41.8. This charge didn't get a full venting on this ladder, however.

But the 43 grain area continues to bear itself out as a good place to be.

Dan

 

[Dan Newberry]

Shot 8 is on the scatter node which I mentioned from the OCW test... it's not surprising that it went a bit wild.

Again, the lower node is almost certainly at 41.7 to 41.8 grains.

 

[steve123]

The accuracy nodes are typically 3% apart... with a node at 43 grains (or thereabout) the next lower one would be down around 41.7 to 41.8. This charge didn't get a full venting on this ladder, however.

But the 43 grain area continues to bear itself out as a good place to be.

Dan

I put on a 30" barrel and am trying the 105's this time around vs 26"/115's for a little advantage in drift and drop so I was more interested in what the higher charges were going to do vs the lower charges, so yeah I'm sorry, that's why 41.7 wasn't fully vetted. From the results it looks like 41.8 to 42.1 were definitely out of the node though.

I really do believe #8 was a funky shot because the rifle recoiled back and left. Be that as it may 5-9 were a hair over 1" at 400Y, scatter node,???

Yep, no doubt you were very close about 43.1 but 43.2-3 I think is where I'll start checking for ES and seating depth.

This test is a lesson on why 100Y one hole groups aren't necessarily the end all be all for long range loads!

Thanks for your help Dan.

 

[Rhyno]

I put on 30" barrel and am trying the 105's this time around vs 26"/115's for a little advantage in drift and drop so I was more interested in what the higher charges were going to do vs the lower charges, so yeah I'm sorry, that's why 41.7 wasn't fully vetted. From the results it looks like 41.8 to 42.1 were definitely out of the node though.

I really do believe #8 was a funky shot because the rifle recoiled back and left. Be that as it may 5-9 were a hair over 1" at 400Y, scatter node,???

Yep, no doubt you were very close about 43.1 but 43.2-3 I think is where I'll start checking for ES and seating depth.

This test is a lesson on why 100Y one hole groups aren't necessarily the end all be all for long range loads!

Thanks for your help Dan.

Group size has nothing to do with the OCW.

 

[Desert Fox]

This test is a lesson on why 100Y one hole groups aren't necessarily the end all be all for long range loads!

My approach is different. A load that won't group at 100 yards is worthless to me.

My 338 Lapua Ackley with 95 grains of Retumbo and 300 SMK will shoot one ragged hole at 100 meters like the 5 shot group in the picture.



And it will kept 20 rounds all clustered together at 1000 yards.