First, OCW test. Multiple Nodes, or am I just that rusty?

[John-K]

M96 Swede, 6.5x55, 22" bbl, SWFA SS10x42, glass beded Butler Creek (steel rod/fiberglass reinforced and free floated forend), Dayton Traister trigger- consistent 1.0-1.1#, prone on a harris.

140gr Hornady SST
IMR4350
CCI200
3.150" OAL

The target is sharpie on lined posterboard. White squares are 1", Purple squares are 3", the purple squares MILed just barely under 1MIL, at what was supposed to be 100yds.

Spot= 41.4, 42.2, 43.0.

Then a "round robin" with 1 round from each group, with a 70-one-thousand count before chambering the next round. I ran the spotters, 1,2,3 before the line was called cold. Then 4,5,6,1,2,3,4,5,6,1,2,3 before it was called again. And finally 4,5,6. Then I cranked the elevation down 3 clicks (.3mil), and ran the 4 rounds @42gr in the lower group of the spotter target with ~5 seconds between each round.

1= 43.8gr 2= 44.2gr 3= 44.6gr

4= 45.0gr 5= 45.5gr 6= 45.9gr



Are there multiple nodes (2,4,6 & 42gr spotters) or is my form just that rusty?

Should I bracket from 44-45gr and run the test again?

Thanks,

John

 

[8nbait]

I would try 44.8 since 45.5 looks like the scatter node. I find it interesting there is not much elevation change in such a large spread of charge weights. That's my opinion anyway.

 

[Dan Newberry]

yes... re-shoot 44 to 45 grains... the place to be is in that area.

 

[John-K]

Ok, now I'm even more confused...
T1=44 T2=44.2 T3=44.4 T4=44.6 T5=44.8
T6=45

I loaded up 5 rounds in case of fliers.

3 rounds, round robin style, Target #5, flier at 4o'clock I called as a miss.



And the final 2 rounds, round robin style, 6,5,4,3,2,1 6,5,4,3,2,1 instead of 1-6

 

[John-K]

Why are you confused? That looks great to me, and agrees with the data from test #1. It's either 3 or 6 and I would pick 6 based on the limited data in test #1. What were your velocities?

Thanks guys,

I'm also thinking 45gr might be the best. I might load up 50-100 of each, and then try them both over the next couple of months. I'm trying to make it out to a 500yd range in August, to work my way out from 200yds, build some ballistic tables and get more trigger time.

The part that confuses me is the difference in groups of the same loads. The weather, according to wunderground.com (weather station is 2 miles from the range), air temp and humidity was within 5* and 10% for the days I was shooting the tests. Wind was minimal.

44.2gr, test 1

44.2gr, test 2


44.6gr, test 1

44.6gr, test 2


I don't have a chronograph, I upgraded my glass instead.

 

[pell1203]

I agree with pinsandpitons that T3 and T6 are the two obvious choices given the two targets from the second set (orange). The 45 grain load from the first set (purple targets) also confirmed this.

Additionally, based on the first set (purple targets) where 44.2 performed quite well I think your sweet spot for the lower node will actually be closer to 44.3 grains since 44.4 was also a very good performer on the second set (orange targets). My logic is since 44.2 and 44.4 performed well and impacted at the same relative point, splitting the difference between the two and loading at 44.3 would be somewhat more forgiving for minor charge weight deviations. Good luck!

Note: Sorry about reply being a bit tardy... started answering and got a phone call and then finished it and posted.

 

[Raufoss]

m96 swedish mauser and 6.5x55 have an 2650-2675fps accuracy node. you should use a chrono in relation with your result.
Also to my eye and personal experience , the T3 could be the good one.
Re-run your test with those two and shoot then at 200-300 yards on more accurate target like the orange one. Make only 3 shot group and make a triangle after that and find the center of this triangle. Mesure the distance form the triangle center to the POI. you will know which three groups come the closest to hitting the target in the same POI. You now choose the powder charge which represents the center of this string.
44.4 should be your OCW charge.

 

[Pinecone]

There should be an accuracy node, every 3% change in charge weight from another accuracy node.

So if you run a large enough range of charges, you should see multiple nodes.