OCW Take 2 **Updated**

[CK_32]

Alright some of you guys might remember about 2 weeks ago I posted a OCW but it couldn't be read due to weather conditions and bad zero on my scope.


Re-shot the OCW and hopefully this one can be a bit more clear.

Info:

Rifle: Rem 700 Tac 308 1:12
Bullet: 175 SMH HPBT
Powder: Varget
Brass: Win
Primer: CCI 200
OAL: 2.800

I didn't get a photo but I did measure with a caliper of all 3 shot groups center mass from point of aim (center) of target.


Pwder Charge (gr.): 43.8 - 44.2 - 44.6 - 45.0 - 45.4 - 45.8 - 46.2 - 46.6 - 47.0

POI from center (in.): .94" 1.05" .95" .43" .12" 0" -.05" -.29" -.55"


So hopefully someone can see a pattern and tell me my OCW.


***Updated See Post #7 ***

 

[CK_32]

Made up a quick graph on Excel for a visual aid to hopefully represent a node.

And it looks like it shows what I thought in my groups I have a node at 43.8 to 44.6 and another at 45.5 to 46.2.

Edit:

Y axis represents POI off by (Inches)

X axis represents powder weight (Grains)

 

[kvwpwr]

Need a picture. Distance from center doesn't help if you don't know which direction from center.

And 47grs is 2gr over book max (hogdgon). Are you checking for pressure signs?

 

[Pinecone]

Yeap, need distance AND direction.

 

[CK_32]

Still no pressure signs at 47gr like last time.

Had a few at 43gr give a sticky bolt but I think that's from how I neck sized.


Every group has a listed number of inches from center vertically. Numbers are listed as in above target.

45.8 was dead center and the numbers with (- , negative) represent shots measured below the center of the target or POA which should reflect on the line graph.

Oddly enough at the higher grains seemed to drop slightly lower in POI.

I also have horizontal measurements (windage) but didn't post because I figured that didn't matter on account the wind was at 3 to 10MPH. Last test was at 10 to 18 mph gusts reason I had to reshoot this.

Also didn't want to post windage if it wasn't relevant and cause confusion.

But if you need horizontal measurements to determine node I will post those later.


But again the chart and numbers given show grain weight and vertical spread if that's what your confused on

 

[Deadshot2]

I also have horizontal measurements (windage) but didn't post because I figured that didn't matter on account the wind was at 3 to 10MPH. Last test was at 10 to 18 mph gusts reason I had to reshoot this.

Also didn't want to post windage if it wasn't relevant and cause confusion.

Wind can have a very pronounced effect on vertical. Depending on the direction and speed it can cause significant rise or drop in the bullet's POI.

Winds from 3 or 9 can spread sideways but any wind from a "Quarter" also effects speed which will cause vertical changes. This effect is also exacerbated by spin drift over longer distances.

I used to totally disregard the "horizontal", dismissing it as "wind or shooter" but then discovered that the loads that were "great" didn't seem to notice wind at short ranges.

 

[CK_32]

Windage measurements

All shots left of center on target. Wind was 1/4 value blowing to the right at 6 - 10 MPH.

43.8gr: 1.27"

44.2gr: .547"

44.6gr: .104"

45.0gr: .939"

45.4gr: .765"

45.8gr: .107"

46.2gr: .051"

46.6gr: .645"

47.0gr: .683"


That's all given info. Hopefully now someone can give me some feedback.


Thanks for all those replying as well. Really appreciate it.