175gr smk OCW First Test

[dustinoif3]

I stumbled onto some 175 smk's at the local shop the other day so I thought I would give them a try. The rifle is a 700 sps 1-12 twist 308. Ive ran ocw's on 168gr bullets and the ocw was easy to spot with them. This test did not go as well.

Test Details: 100y fired round robin with 3 to 4min cool down period in between shots
Sighters: 44.2, 45.1, 46
Group 1: 46.5
Group 2: 46.8
Group 3: 47.1
Group 4: 47.4 (47.5 is book max)
Group 5: 47.7 (Only fired one round due to hard bolt and extractor mark)
The bottom right target was 5 shots of 168gr smk's. I was playing with seating depth on that group. They were fired after test.

Load Details:
Cfe 223 powder
FC Brass
CCI Large Rifle Primers
175gr smk loaded 2.265 Ogive (2.270 is mag length)


Any input will be appreciated. I felt good behind the rifle and the wind was 0 value

 

[pell1203]

I think I would try another three rounds each at just under and just over 47.1 grains. Maybe even limit it to 47.0, 47.1, and 47.2 just to see if you can replicate the prior 47.1 group.

The 46.8 grain load could be a scatter area transitioning through an accuracy node (around 47.1) and then going towards another scatter area around the 47.4 load. My thought is the 47.1 range may the accuracy node in between that you are looking for... hence my suggestion above.

 

[dustinoif3]

Thank you for the reply Pell. My first thought initially was to go above and below the 47.1 because the rifle perked up there. What made me second guess is that there wasn't a whole lot of wiggle room on either side of that node before it scattered. My 168's OCW was plain as day. Had a 47.7, 48 and 48.3 all in the zone before it scattered. Maybe this brass, bullet and powder combo is a little more finicky?

 

[dustinoif3]

The only other thing that makes me wonder is that book minimum was 45.5 and I jumped way past it with my first group after doing all the math