I've only one OCW exercise once before, and it was a while ago, and I remember having some issues "reading" the results.  Wondering if the hive would be interested in lending a hand with today's results?


150gr Hornady:

Attached File



165gr Nosler:

Attached File



I drew horizontal lines out from each target dot to help make it easier for me to read vertical deviation from the center, and that helped a lot.  So did finding the centroid of each group.  I hadn't done either of those in the past.

Still, I'd like to see what your interpretation is vs what I came up with myself (I'm thinking my gun likes slow bullets).

Thanks.

OK, here's how I'd read them (absent chrono and other data) if they were my groups:

150gr Hornady
- 44.3, 44.7, 45.2 have very similar POIs.
- 45.2 begind to scatter, and so does 45.7
- 46.3, 46.5 have similar POIs, maybe 46.0 as well
- 46.8, 47.0 scatter
- Newberry indicates good nodes and scatter nodes are each often ~3% (~1.4gr) apart.

So I'd explore 44.7hr and/or 46.3gr with closer spaced charges and then, if successful, seating depth changes.

165gr Nosler
- 43.4, 43.8 have same POI
- 45.3, 45.5 look similar too
So I'd explore those two areas further as above

GL !

Thanks for the reply.  I can post chrony data if it would help, but I think my battery was dying as my results were a little inconsistent at times.  I think I can correct the strange readings with averages from the others in the string.

Ya, chrono data is always very useful(said the guy without a chrono ). If you're getting great groups but have a high SD those great groups won't be as great at longer ranges.
Also why are only shooting 3 shot groups? I would try 5 shot groups.

150gr

44.3gr 2614 2661 2635
44.7gr 2672 2688 2650
45.2gr 2677 2721 2743

46.0gr 2760 2749 2801
46.3gr 2760 2783 2795
46.5gr 2743 2777 2795


165gr

43.4gr 2496 2464 2492
43.8gr 2525 2464 2487
45.3gr 2583 2594 2564
45.5gr 2614 2583 2578* (mild pressure signs, not gonna pursue)

This is a 1:12 20" R700 LTR .308, Varget.

Thanks guys!

The data has a lot of distance between points, so may not help refine conclusions. How consistent do you think your powder charges actually were?

Having said that, the average velocity of your 46.0, 46.3, and 46.5  are 2770, 2779, 2772 respectively . . . though the 46.0 average was raised by a 2801 outlier. 46.3-4 may not be a bad landing place.

Thanks man.

It took me many hours to load this ammo.  It was all loaded in the same brass, same primers.  I trickled each load by hand and weighed each load three times before charging each case.  Scale was calibrated every five rounds loaded.  Ammo was kept in the shade at the range, and 2-3 minutes was allowed between each shot, using wet rags to cool the barrel and chamber between shots.  I shot 1 to 9, 9 to 1, 1 to 9 as prescribed by OCW.

Confirming the 150gr Hornady with Varget, target #1 in the initial post above.


6. One each of 46.2, 46.3, etc. to confirm zero (first target shot) (2726, 2721, 2737, 2754, 2749fps)

1. 46.2gr 2749fps, 2721, 2726, 2732, 2743

2. 46.3gr 2749fps, 2760, 2726, 2737, 2749

3. 46.4gr 2749, 2760, 2732, 2737, 2737

4. 46.5gr 2715, 2732, 2721, 2749, 2732

5. 46.6gr 2715, 2737, 2760, 2743, 2737


Attached File



I'm not impressed with ES and SD, although this was loaded in the same painstaking manner as the last, spooned in 46gr and trickled the last bits, confirming on two different scales several times, etc.  Brass used was once-fired FGMM full length resized, primer pockets uniformed and deburred.

What do you guys think would be the most reliable load?  Looking to move on to seating depth testing next.

Thanks.

So you want to say 46.3gr because it's the best 5-group . . . but 0.1gr on either side of it doesn't look so good, right.

Don't know the velocities and don't know what scale you have, but I'd choose mid-way between 46.5 and 46.6 based on the target alone . . . probably 46.4 as a target because I can do that as easily as any other number lol. Those two groups have the same POI and the outlier in each group is not due to vertical spread.

Good luck with depth checking.

It's hard to tell what you have going on there.  If I had to pick a spot to look at, I'd look at #3.

Edit: and #4

Move to 300yds and shoot 3 simple 10rd ladders with .4gr increments over a chrono.

Also, are you seating for runout?

What I mean is, start to seat a bullet, then stop midway, rotate the cartridge in the shell holder 90°, then fully seat.

This has proven to reduce bullet concentricity runout in testing with control groups by lot, with measurable results on-target as well.

At some point, you feel like you're spinning your wheels, and just pick a load that seems decent in your rifle, produce it, and get some trigger time.

The distances where the accuracy level you are chasing start to matter are beyond what the .308 is capable of with the bullets you're shooting when looking at the importance of wind call, so it doesn't really matter.

At what distance were these groups fired?

What are the group sizes, mean radius, point of impact differences?

My quick guess, you and your rifle are only capable of shooting groups of about 2-3" (I'm guessing on the group sizes and assuming they were first at 100 yards).  At that level of accuracy, you should not worry too much about finding a node.