OCW test, need input

[LILBUCK]

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Rifle 300WM
WIN Brass
H-1000
Federal 215M
208A-MAX

This test was shot at 203 yards, the wind was on and off but id say no more than 2-3 MPH.The wind was just enough to slightly move the tops of the tall grass. Every shot felt good so don't think i pulled any but it is possible. Shot off of front and rear bags. I don't really make anything useful from these results. Can someone with more knowledge than I make sense of this. Thank you for your input

 

[seanhagerty]

Re: OCW test, need input

OK, OCW's are best shot at 100 yards. Dan Newberry has a lot of info at his site. Do a search for ocw and load development.

OCW is based on the way the barrel vibrates when the round is fired. The best load is when the barrel harmonics are the same with a slightly higher and lower load than the one chosen. (That means the group is impacting in the same place on the target for all three loads.) Once you find the best load, you can tighten the grouping up by adjusting seating depth.

Based on what I see, I would pick the 77.1 load and then vary seating depth to tighten it up.

 

[trailrider121]

Re: OCW test, need input

I see three that are close and 77.1 being in the middle however, not that great of ocw. 77.4gr is moving poi higher.78gr looks to be a scatter node so another 1.5% higher should put you in the high node. My guess would be 79-79.7 grs would be next ocw. Watch for pressure signs though.

 

[LILBUCK]

Re: OCW test, need input

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Sean Hagerty</div><div class="ubbcode-body">OK, OCW's are best shot at 100 yards. Dan Newberry has a lot of info at his site. Do a search for ocw and load development.

OCW is based on the way the barrel vibrates when the round is fired. The best load is when the barrel harmonics are the same with a slightly higher and lower load than the one chosen. (That means the group is impacting in the same place on the target for all three loads.) Once you find the best load, you can tighten the grouping up by adjusting seating depth.

Based on what I see, I would pick the 77.1 load and then vary seating depth to tighten it up.</div></div>

I have read Dans website and have a basic understanding of the test, an expert i'm not. I was expecting to see more definitive results. Do you think the results would be any better at 100 yards? To me all the groups are scattered. Thank you for your help.

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: trailrider121</div><div class="ubbcode-body">I see three that are close and 77.1 being in the middle however, not that great of ocw. 77.4gr is moving poi higher.78gr looks to be a scatter node so another 1.5% higher should put you in the high node. My guess would be 79-79.7 grs would be next ocw. Watch for pressure signs though.</div></div>

What do you mean not that great of an OCW, being at 77.1gr or my test results? I was actually getting faint ejector marks and slight smearing on the head at the 78.0gr but bolt lift was fine.

I did a ladder test with this same gun a few years back and with the help of the hide i settled on 77.2gr. I have always felt this gun should shoot better considering the amount of money i have in the build. Maybe i need to very seating depth as i have never done that. thank you for your help

 

[8nbait]

Re: OCW test, need input

I would load up some at 77, 77.2, 77.4 77.6 and give it another go. Then pick the best load and start playing with seating depth if not satisfied.

The other option would be 76.5, 77, 77.5 and 78. Shoot at 100 and then fine tune with .2 on each side of OCW (should all shoot about the same) get the best of those and start playing with seating depth.

This OCW method has worked great for me. I find it more conclusive than ladder testing.
good luck, Gary

 

[jsthntn247]

Re: OCW test, need input

Load 3 up at 76.5, 76.8, 77.1, and 77.4. Load them at a different seating depth than your last test. Mine likes the 208's just touching the lands or .005 off. Looks to me like your node is 76.8, which is a known OCW for H-1000 and the 208's.

 

[gvanhyning]

Re: OCW test, need input

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: jsthntn247</div><div class="ubbcode-body">Load 3 up at 76.5, 76.8, 77.1, and 77.4. Load them at a different seating depth than your last test. Mine likes the 208's just touching the lands or .005 off. Looks to me like your node is 76.8, which is a known OCW for H-1000 and the 208's. </div></div>
Not to step on any toes, but I would not do anything with seating depth until I have found a charge weight to work with. Once you have the charge weight then try shot groups with different seating depths. Personal opinion.

 

[LILBUCK]

Re: OCW test, need input

I will be loading up another test batch tonight and hopefully shoot them this weekend. I will work on seating depth after this test and report the results. Thank you all for the input.

 

[NoFail]

Re: OCW test, need input

Are you shooting them "Round Robin"? I didn't do that when I first started OCW testing. I saw an immediate improvement when I started shooting them Round Robin. The groups tightened up and it was easier to discern between the keepers in the accuracy nodes and the not so desirable charge weights.

 

[shoot4fun]

Re: OCW test, need input

Read Newberry's writing on OCW and follow it to the letter. 100 yards for distance and no more. shoot off a good solid rest and bag. Get on the bench. Once you have a solid OCW then work on seating depth. For seating depth testing I start just in the lands and work back by .002 with each change. Go to 15 or 20 thousandths off because you may be surprised at what you find.
If you want to shoot at longer distance use the ladder test method.

 

[LILBUCK]

Re: OCW test, need input



<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: NoFail</div><div class="ubbcode-body">Are you shooting them "Round Robin"? I didn't do that when I first started OCW testing. I saw an immediate improvement when I started shooting them Round Robin. The groups tightened up and it was easier to discern between the keepers in the accuracy nodes and the not so desirable charge weights.</div></div>


Yes i am shooting "Round Robbin" and this weekend will be at 100 yards. It does make me curious as to why it would affect the results if shot 3 in a row or 1 charge weight at a time.


<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: shoot4fun</div><div class="ubbcode-body">Read Newberry's writing on OCW and follow it to the letter. 100 yards for distance and no more. shoot off a good solid rest and bag. Get on the bench. Once you have a solid OCW then work on seating depth. For seating depth testing I start just in the lands and work back by .002 with each change. Go to 15 or 20 thousandths off because you may be surprised at what you find.
If you want to shoot at longer distance use the ladder test method.</div></div>

I was and will be shooting prone off of front and rear bags. I don't shoot at the range so i don't have a bench. Maybe i need to build a portable one? The COAL is .010" off the lands right now, we'll see what happens. and ill report back. Thank you all for helping the less educated.