Any OCW experts to verify my 260 remington OCW test?

[bani]

Any OCW experts out there who can verify my OCW test for 260 remington?

i did an OCW from 41.1gr - 43.1gr in 0.4gr increments.

based on the targets below, i suspect i want to use 41.1gr.

my scope sight-in loads were 41.9 and they chrony'd at 2802fps with S-D of 11.

http://i.imgur.com/2XLFr6X.jpg

http://i.imgur.com/yaD3Sls.jpg

http://i.imgur.com/kTHPn6s.jpg

http://i.imgur.com/rFbxTUo.jpg

http://i.imgur.com/nSMlhpy.jpg

http://i.imgur.com/6V0O4Bs.jpg

[Mozella]

According the the OCW instructions you need to pick the "middle" charge weight of three which have a similar POI. You don't supply the Group Offset Data, so I can't say for sure, but just eyeballing the images I'd say that 41.5gr is your starting point for testing seating depths and neck tension because it looks like it's the "middle" of three groups hitting the target in roughly the same spot. The lower charge weight of 41.1 shows better performance, but it can't be the "middle" so perhaps further testing at even lower charge weights is warranted.

I'm not a big fan of OCW and if this were my load development, I'd take a further look at the highest charge weight. You don't label it, but I assume the last image is based on 43.1gr. Look at the graph of MOA, Mean, and Group Height (Vertical). The highest charge weight shows the best performance, especially the best MOA and Mean (Average to Center). The vertical ain't bad either. To many people, including me, the group Mean is a more important factor than MOA and the more shots in your group the more meaningful it can be. So, assuming you aren't showing pressure signs at 43.1, I'd load a little below that charge weight and work my way up a little higher until performance started deteriorating or, it goes without saying, excessive pressure signs appear. Be careful, as always. And, assuming you can live with the MV associated with the lower charge weights, you might want to test even lower charge weights as well. If this were easy (or cheap), everyone would be doing it.

Sometimes all the bullets fall into the same hole, and vice versa, for reasons we don't fully understand. Remember, we're trying to gather data measured to the nearest .001" produced from 100 yards away with a device held by a live human and a bullet traveling through unknown winds. So making a decision on one test session with only five shots per group is a fools errand. But you're on the right track and it appears to me you have a great starting point. But, as far as I'm concerned, in order to make a decision you can rely on, you need to do your best to duplicate parts of this test session and perhaps extend both the low and high end of your charge weights to see what happens.

Unfortunately, your test produced data which is frustrating to the load developer. What you hope to see when you test 5 to 7 different charge weights is poor performance at each end with good results somewhere in the middle. Unfortunately, your worst performance is in the middle with increasing performance at both the high end and low end with a hint of even more promising performance at untested charge weights, both higher and lower. Dang.

Any of these groups will kill one of God's furry creatures, but if you're shooting matches against other highly competitive shooters you can be sure some of them have done their homework. You want to show up with a load recipe you KNOW is good, not just one you HOPE is good.

Don't worry, you'll find Nirvana just about the time you wear out your barrel. :behindsofa:

https://farm5.staticflickr.com/4296/36113194486_a21d342d02_b.jpg (https://flic.kr/p/X2cyyf)2017-07-25_045545 (https://flic.kr/p/X2cyyf)

[jpdown]

I'm not an expert, but based on doing numerous OWC test over the years, it looks like you have nodes at 41.1 gr and 43.1 gr. I'd retest 43.1 gr with .2 gr load increments above and below. I suspect 43.1 gr is already at or near your max load. If so, then retest around the 41.1 gr load. Your brass will last longer.

[jim_k]

The last two groups have a very good vertical dispersion, and both hit higher than the other groups, relative to POA. That POI is consistent between the two groups. This looks like the barrel is at the top of a node. Best load may be somewhere higher than 42.7 gr, and possibly somewhat higher than 43.1 gr, if that doesn't cause pressure issues. Time to change seating depth at a given charge, such as 42.9 gr, then work the powder load in 0.2 gr increments after you see your best groups from a given seating depth. That's how I'd do it. You'll get this done within the next 20-40 shots, then you're good for a very long time.

[SageRat Shooter]

43 gr. H4350 using the 143 ELDX is my load... Pressures are right at max and I'm using Lapua brass and WLR primers. I've got a 260 Remington "Match" chamber.

[Robinhood]

What powder scale are you using? I like the 42.7 to 43.1 range with your rifle. Work on the seating depth. Go out to 2 or 3 hundred yards.

[cowtownup]

Its hard to deny the low vertical dispersion and the similar POI on the 42.7 and the 43.1 charge groups... I would maybe shoot 42.6, 42.8, 43, and 43.2 and try to nail down where the middle of that node is and then play around with seating depth... Or just go straight to 42.9 and start messing with seating depth... If you are like me, I'll burn a **** barrel up trying to find a load for it... LOL.. I stay away from the 800-900 round count calibers....

[m12lrs]

Would be nice to know powder and bullet

41.1 and 41.9

Obvious choice from an OCW evaluation. Go to the middle and do a seating test followed by fine tuning the load might just.tighten them right up.

42.3 42.7

Now this is not an OCD evaluation but i have seen this pattern before. Vertical stringing followed by horizontal stringing. Usually somewhere in the middle is a node. If you want a little more velocity you might try to find it. It will be a narrow one though.

Last group

Tight. But no information. Position on the target is completely different than anything else. Can you enlighten us. I try to stay away from max loads just.for brass life but often there is a very accurate node.there.

[Zero333]

I would test 43 to 43.4 in 0.2gr increments.

But looking at your targets... 43.1 is obviously the smallest group and looks to be right around a node.

41.5 is your other node but around 43 gr looks like it might be the better node.

[bani]

in the interests of preserving brass, powder, and barrel, i decided to explore the lower node.

http://i.imgur.com/qXdY5Ho.png

http://i.imgur.com/CDSq9cP.png

http://i.imgur.com/KoSdQc2.png

http://i.imgur.com/SBvIvkN.png

http://i.imgur.com/FPjtJW7.png

[m12lrs]

i would recommend a seating depth test. you might be suprised what you find. i bet they will tighten up considerably

[Zero333]

If seating depth testing of 41.1 gr doesn't satisfy, I would pursue the node around 43.2 gr

[jim_k]

Don't sweat the brass life issue. That has more to do with whether you oversize the case and make it stretch a lot with each firing than it has to do with the load's pressure. I second Zero333. Anyway, you're very close, and you are acquiring some usable information for future testing. What's this for? If it's for paper-punching, stay with the low node. If it's possibly going to be applied for long-range target shooting or for hunting at longer ranges, go to the higher node.

[bani]

ran out of hornady projectiles and getting low on h4350. scored 8lb of h4381sc and my berger hybrids arrived so decided to give it a try, using nosler load recommendations.

http://i.imgur.com/bxc5YM2.png

http://i.imgur.com/3BHCPkJ.png

http://i.imgur.com/YCYPW9n.png

http://i.imgur.com/bJEL4gn.png

http://i.imgur.com/bkbwCJ9.png

[Zero333]

H-4831 (and 4831sc) is ALWAYS my first go to powder for load development in the proper cartridges.

It's always accurate.

44.4 is a good looking group, but on the other hand 44.0 & 44.2 had the same point of impact and little vertical dispersion.

You can load some a 44.1 and play with the seating depth.

[bani]

on the 44.0gr target i pulled the flyer to the right and knew it as soon as i pulled the trigger.

bryan litz @ berger says hybrids are supposed to be insensitive to seating depth?

[jim_k]

All bullets are sensitive to seating depth. Litz' reference on the hybrids means that they are a lot less sensitive to seating depth. Some VLD's will barely shoot under 2" at a seating depth your rifle does not like. At a different seating depth, the same bullet may shoot 0.3". With hybrids, most any load might shoot about 1", or even 0.75" groups, but the best seating depth will get you down to 0.3".
BTW, you're done as of that last group. Anything beyond that is just showing off! Feel free to show off, but you're officially done.

[m12lrs]

in my 6BR with 105 hybrids seating depth test from a 0.010 jam to .020 off at .005 increments were performed. two nodes .005 off and .020 off were found. further testing found the .005 off seating depth was best.

a final charge weight test was performed. at .05 off any charge from 29gr of varget to 29.9 gr varget will shoot in the 3s and 4s. at 30 grs of varget it shoots like this.

http://i1056.photobucket.com/albums/t379/rcoody1/sorted%20target1_zps2a0j1q8i.jpg

[WV1951]

^^^^^^^^^ Now this is showing off.:cool:. Love it.

[WV1951]

Oops.