Was finally able to get the testing done correctly today. Please let me know where you think my best node would be so I may move further.
Thanks in advance!
CJ
Thanks in advance!
CJ
Ok...Here it is...the correct OCW test. What do you think?
- Thread starter clrems77
- Start date
What cal? Powder? If your running a .308 I'd run 45.7/45.8. Nice looking groups, but don't settle on one until you shoot it out to 300. 100yds id where I start, but I always verify at a minimum of 300yds, then stretch it on out. My 6BR shot lights out at 100 but opened up at 300, and I tuned from there, and found a better node almost 1gr higher.
It isn't just about group size...with ocw you are trying to find a load that shoots to the same poi even if you shift up or down a few tenths in powder. For that reason I would look at trying 45 grains. One step above and below shot to nearly the same poi, so I would expect it be a pretty stable load. I'm curious, since your results are not real definitive, is this is from a fairly heavy profile barrel of around 20 in? Longer, thinner barrels have groups that breathe more on an ocw test.
It is obviously critical to shoot really good groups in these tests so that group size corresponds to the load's potential, and these look pretty good. I agree with groundhog that you should take a look at whatever you choose out at 250-300 or so with a few 5 round groups on a day where wind isn't much of a factor. If those groups confirm your testing you are set.
It is obviously critical to shoot really good groups in these tests so that group size corresponds to the load's potential, and these look pretty good. I agree with groundhog that you should take a look at whatever you choose out at 250-300 or so with a few 5 round groups on a day where wind isn't much of a factor. If those groups confirm your testing you are set.
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Thanks for the correction guys! I'm running an AIAE in .308 20" barrel with break. This is Hornady Amax 168's over IMR 4064, Hornady match brass with FC 210 primers.
I would look around the 45.7 for your load. The important thing with the OCW test is to have 3 consecutive groups hit at the same point of impact. To put it in words as I don't know how to edit photos, 45.4, 45.7 and 46.0 all have a POI at roughly 8 o'clock with the center of the groups being right on the edge of the red square.
I would run a test with 45.7 grs and vary the OAL. I like to run an OAL length test in 0.020" increments. For example, if your initial test was shot at an OAL of 2.800, run the next test with 5 round groups at each of the follow: 2.780, 2.800, and finally 2.820. One of these should shoot better than the others.
I would run a test with 45.7 grs and vary the OAL. I like to run an OAL length test in 0.020" increments. For example, if your initial test was shot at an OAL of 2.800, run the next test with 5 round groups at each of the follow: 2.780, 2.800, and finally 2.820. One of these should shoot better than the others.
Your 45.7 gr group is a nice tight group, so you may not really benefit from running an OAL test. You could certainly skip ahead and due as KYpatriot suggested and run some groups at a further distance to see how the load holds up.
Agreed. Take it out to 400 yards and post some pictures. My guess it will shoot good out there too
No, the theory behind ocw is to manage barrel vibration. The barrel vibrates like a tuning fork, and you are trying to find the velocity you need such that the bullet exits the muzzle as it stops just before reversing direction at the end of an oscillation. A short heavy barrel oscillate tighter with less amplitude than a longer thin barrel, so the ocw results are closer. The nodes are closer and less pronounced. That's a good problem to have, and why it is easier to get short stiff barrels to shoot well. Heat is another problem entirely which thin barrels will obviously suffer from more than heavier barrels.
KYP
Being that I value your opinion, What do you think about the 45.7 node? I see what your speaking of at 45, but I also see another node at 45.7. Is this just another node at a higher charge? Shoot both nodes at 200-300 yards?
Thanks again!
Yes try 45.7 it looks close too. See what it looks like at 300 if you can get a low wind day, and if you have access to a chrony check the extreme spread. Looks like this rifle will shoot. If you are not seeing pressure then I see no reason not to pick the highest node you can. I don't use that powder so I'm not sure of the temp sensitivity. The only caution about choosing the highest node is that on a really hot day if your ammo gets hot it can push a load on the pressure limit over into popping primers and such.
Great, thanks! Im in southern CA (I know,I know) where the weather is pretty stable throughout the year. This test was conducted on a day of roughly 85 degrees so it wont get too much hotter during the summer months. Thank you again for your help and education!
CJ
I'd leave the OAL alone. If you were shooting VLD's then ok but the 168Amax is pretty jump tolerable, and the 168/175smk's even more so. I'm shooting a 20" tube in my 5R also, I liked 4064 but settled on Varget, and h4895, but with groups like that, I wouldn't switch powders, all you need to do is load 5 ea in the 43.8/ 45.7 range, and if it stays under 1.5" @ 300, then your good to go. Like me you'll need the extra fps, from that 20" tube with the hotter load to get to 1k.
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