OCW opinions?

[Kampfjager]

This is a OCW test i did with a 308.... whats your thoughts on what you see here?

 

[birdiemc]

I'm saying 42.1 looks good, not a whole lot of POI shift 1 up and 1 down, what distance are you shooting at?

 

[Kampfjager]

I'm saying 42.1 looks good, not a whole lot of POI shift 1 up and 1 down, what distance are you shooting at?

100 y

 

[Kampfjager]

Its..
168 SMK
Lapua brass
CCI br2 primers
Varget
Seated at mag lenght

 

[Kampfjager]

Oh and its a factory 700 5r milspec off a harris bipod....

 

[Mike 338]

I'd go 42.2 and mess with seating depth as needed.

 

[Kampfjager]

I'd go 42.2 and mess with seating depth as needed.

Why not 43.1?

 

[Blackdirt Cowboy]

Yep. I thought somewhere around 43 looked good. 42.9 to 43.1 there's very little poi shift. I'd load 43 and play with seating depth. All this assuming you had no signs of pressure.

 

[Kampfjager]

Yep. I thought somewhere around 43 looked good. 42.9 to 43.1 there's very little poi shift. I'd load 43 and play with seating depth. All this assuming you had no signs of pressure.

Absolutely no signs of over pressure and the velocity of 43.1 was 2,620 fps.... seems to be a conservative load....

 

[birdiemc]

Honestly there's not a HUGE shift in POI across your whole range...
The idea behind OCW, as I understand it, is to allow you to determine what charge you want to use that gives you some wiggle room in both directions without much shift in POI. So you have to determine for yourself how much wiggle room you need. If you are capable of loading and achieving single digit es/sd's then you need a little less wiggle room than the guy who just crammed his first bullet in a case this morning.
My 2 scales suck, so I like the thought of 42.1 because you get +-.2 gr without effecting POI more than the size of your best group in that picture.
As Mike stated, 42.2 would be good, less POI shift, less margin. What are you comfortable with?

And 43.1 looks awesome, but in the spirit of OCW you would load 43.0 and play with seating depth.

 

[Mike 338]

Why not 43.1?

Well, this is a OCW Test which is a quick and dirty method of determining which charge falls into an area of least harmonic "uniqueness". The idea with this test is not necessarily to pick the tiniest group but to triangulate your three shot group and identify the spot where the center of that 3 shot group would be. When you find two or three adjacent groups whose centers are virtually in the exact same spot, those powder charges show the greatest sweet spot potential. If you look at 43.1, it's center is at 12:00 of your target dot but the two groups on either side are at 9:30 or 10:00 o'clock. If 43.1 was more in the 10 o'clock position, that would be the obvious winner.

 

[brentc]

I say 42.2 for this test, however I think you have room to push it up.

 

[birdiemc]

Its..
168 SMK
Lapua brass
CCI br2 primers
Varget
Seated at mag lenght

I agree with Brent you do have room to push it up higher if you wanted to, I'm doing the same load development right now, factory 700 rem, same everything, except federal brass over here, and I'm about to load up at 45.0 to start working seating depth.

 

[Kampfjager]

Well, this is a OCW Test which is a quick and dirty method of determining which charge falls into an area of least harmonic "uniqueness". The idea with this test is not necessarily to pick the tiniest group but to triangulate your three shot group and identify the spot where the center of that 3 shot group would be. When you find two or three adjacent groups whose centers are virtually in the exact same spot, those powder charges show the greatest sweet spot potential. If you look at 43.1, it's center is at 12:00 of your target dot but the two groups on either side are at 9:30 or 10:00 o'clock. If 43.1 was more in the 10 o'clock position, that would be the obvious winner.

I see what your saying.....