308 OCW results, comments please.

[Shakeber]

Here are the results of an OCW that I performed yesterday. Great day to shoot, very little wind and ~60 degs. F.. I am shooting a Rem 700 5r in 308. I loaded 3 rounds each, all test rounds in Hornady Match brass, using RL-15 under Sierra Gameking 165 gr. bullets with Winchester primers. The loads were:
#1 = 42.2 gr.
#2 = 42.5 gr.
#3 = 42.8 gr.
#4 = 43.1 gr.
#5 = 43.4 gr.
#6 = 43.7 gr.
#7 = 44.0 gr. (my max.)
#8 = 44.3 gr. (max plus one graduation)
No overpressure indications thruout the exercise.
Attached is a url link to view the targets. Your comments are greatly apprciated.

http://i54.tinypic.com/15ek9c.jpg[/IMG]] I hope this works.
Thanks in advance.

 

[jonbearman]

Looks like 42.5 is the one to play with! I always wanted a 5r remington,dont have the money.

 

[Shakeber]

That's what I was thinking. 42.5 gr. Thanks jonbearman!

 

[RonAKA]

You have lots of data to work with. What distance was it shot at?

Here is what I would do next. Draw a horizontal line below your aim point the same distance for all targets. Chose a number of inches that is below your lowest point of impact. Measure up from that line to the center of each bullet hole (vertical distance only, not sideways or diagonal), and record the number (elevation). The purpose of the line is just so you can work with positive numbers.

Then for each load it appears you have 6 shots spread over two targets. Calculate an average elevation of those 6 shots for each load. Then plot a graph with grains of powder on the horizontal axis, and your average elevations for each load on the left. See graph below as an example.

What you are looking for is a flat spot(s), where grains of powder increase but elevation does not. The middle of this flat spot is a potential sweet spot.

 

[Shakeber]

The distance was 100 yds. I inadvertently copied same target twice, so it was actually only 3 shots per load/target. Thanks for your input. I do have work to do. The fun has begun!

 

[navyrad8r]

shake,
42.5 and start tinkering with seating depths next. when those primer pockets loosen up, grab some wolf or tula primers and keep shooting.
cheers,
doc

 

[whiskey08]

what navyrad8r said

nice groups !

 

[Shakeber]

Thanks Doc and whiskey. 42.5 gr. is it. I will probably load some at 42.2, 42.3, 42.4, 42.5, 42.6, 42.7 and 42.8 and head back to the range. Then i will play with seating depths. Thanks all!

 

[necchi]

Sure the 42.5 looks good, but so does 43.7

I'd skip the 42.2-42.3 and 42.7-42.8 and re-test the 43.7 being sure to give the gun a chance to cool tween shot's.
I run the OCW too, and a feller can get tired of it by the time those last 3 shots go down and rush it a bit too finish.
I want the best load my gun and me can handle, and that includes velocity.
If the 43.7 proves the second time, that gives you another node to look at.

I've only been loading a couple years, but one thing I learned pretty quick is if I really want the best for my gun, one box of bullets ain't enough to test AND have some left for use beyond testing.
Sure glad I didn't start loading too save money,

 

[Shakeber]

Thanks necchi, but when I read the instructions for OCW it seems that I am looking for POI. 43.7gr. is the only load that shot in that area. I don't think that it is a good candidate according to the instructions. Yur comment is greatly appreciated and I will consider.

 

[Heavies]

I'd tend to agree with necchi.
Looks to me like 43.1 is your 'scatter node'; 1.5% up falls around 43.7. Also, shots 5,6,&7 looks to be close POI
I'd try both the lower and the higher node.

 

[260Ravage]

Shake: It is obvious you can you your part well in shooting the rifle and you found a sweet spot. You will learn lots by moving your target to 200 yards and doing about the same test keying in on 42.3 --- 43.0. Good luck and keep us posted. I envy you.......yesterday our high temps was -10deg with 30mph winds.

 

[Shakeber]

Thanks for your input. I will keep trying.

 

[Shakeber]

I have triangulated the shooting results. All measurements are from the center of each shot. I also calculated the mean centers of the triangles. Green dots represent the mean centers of the 3 shot groups. I also measured from center of POA to center of green dot and results are:
#1 = 22/32" below
#2 = 20/32" below
#3 = 13/32" below
#4 = 14/32" below
#5 = 20/32" below
#6 = 6/32" below
#7 = 2/32" above
#8 = 1/32" above
You can see whether the green dot is to the right or to the left of Point of Aim. Comments are greatly appreciated.
I made blue triangles to indicate the center of each shot.

 

[DoubleUp]

Seems doubtful that you could hold exactly the same on different targets, which might then throw your calcuations off a bit. To me it is pretty obvious that you have a wide node on the lower numbers 1,2,3,4,5. Then 6,7,8 appear to be climbing to another node with the velocity increase and might actually tighten up a little higher if you can go up without pressure.

You can download this free software which will help you with you calcuations. See link below.
http://www.ontargetshooting.com/download.html

 

[Heavies]

I agree with Double up on using OnTarget software and using same type of target to aim at.
Here is an OCW I shot using 95SMK's in my 6br. I just used word processor to make X's at an appropriate size and font. This target is very easy to hold dead on and exactly the same spot at 100yards.

The obvious scatter node is at 29 grains, this puts my OCW right around 29.5.
In went with that and messed with seat depth, and settled on 29.4 to keep pressures in the workable zone for many rounds with out cleaning and temps that start low and rise throughout the day when I shoot.
This load is very good and repeatable in my rifle.

 

[Shakeber]

Thanks Doubleup and Heavies. I am downloading the software now.

 

[RonAKA]

See the graph I did in the window below. I think your best potential nodes are at about 42.9 grains, and 44.2 grains. There may be one at 42.2. Not sure about the 43.4.

My thoughts would be to pick the one you like and do another ladder around it at 200 yards or more. I think to some degree accuracy is getting in the way of seeing the ladder vertical effect. Going to a longer distance should help. I would use separate but identical targets. The 6BR Targets at the top of the page at this link may work for you, depending on scope power.

http://www.accurateshooter.com/shooting-skills/targets/

 

[Shakeber]

Thanks a bunch RonAKA, very interesting!