OCW Help Please

[he lives]

I posted this yesterday, but wondering if my post got picked up by spam filters? If this is a repeat please delete mods.

I'm developing a hunting load for my 308 using 165NBT and Varget. To start, I shot an OCW test at 100 yards using 3 shot groups at each powder weight. I was hoping to get some of your input on where the best charge weight might be. Thanks!

 

[he lives]

Forgot to add:

- On the first row of groups (42-43.5), the first round of shots all landed lower than the rest of the group. The group at 42 is hard to tell from the scan, but it had the lower shot, and double holed the second two. Then, 42.5 - 43.5 had the lower shot and the second two shots on each were touching.

- I've only shot a couple of these tests and certainly no pro, but it looks like there may be a scatter node at 45 grains and 47 grains. I've read that the accuracy should be approx. 1.5% above or below the scatter node. This seems to be confirmed at 45 grains given that 44.5 and 45.5 (about +/- 1.1%) are very tight groups.

- Since this will be a hunting load, I'd like all the velocity I can get. Do you think its worth shooting more groups around 47 to see what i get there (being careful for pressure signs of course)?

 

[Dan Newberry]

your charge weight graduations are larger than I like to see, but I think that 45.5 is going to be repeatable... if that's too much pressure, 43.5 looks good as well. These nodes don't seem to be spaced as you'd normally see them, but the target data is there.

 

[mxjunky78]

your charge weight graduations are larger than I like to see, but I think that 45.5 is going to be repeatable... if that's too much pressure, 43.5 looks good as well. These nodes don't seem to be spaced as you'd normally see them, but the target data is there.

+1 I would also start with 45.5gr and adjust seating depth to see if you can improve results although from the looks of it, not much room to improve. Good shooting.

 

[majohnson2]

5 shot groups will give you a bit more info. I think most use .3grs steps. Try redoing 45.5, going back to 45.2, 45.5, and 45.8 and switch to 300yds.

 

[he lives]

Thanks for the input guys.

Dan - you mentioned that the weight gradations are larger than you like to see. My logic was to shoot a broad range of charge weights and try to identify potential nodes without burning through too much powder. I had planned to then shoot another test with smaller increments around the possible nodes. With that said, do you think it would be useful to shoot another test from 45-46 in 0.2 grain increments? Or do you think the results show 45.5 to be the best load to go with?

 

[he lives]

5 shot groups will give you a bit more info. I think most use .3grs steps. Try redoing 45.5, going back to 45.2, 45.5, and 45.8 and switch to 300yds.

I just saw this after I posted a reply. My normal range goes to 200 yards, so I could shoot more groups at 200 yards, but not 300. I see what youre saying though...if 45.2, 45.5, 45.8 are similar, I can confirm 45.5 as my node.

 

[918v]

I think that while 45.5 is prolly your node, it is also real hot. Too hot for me.