Re: 308 win. Varget results
I have always found accuracy to be around 2500 to 2600 with 180's, 165 and 8's. I have not shot the 175, but for my guns I would look in the 2550 to 2650 range.
I would fire loads in this range at one target with one round at each load in two tenth grain increments while plotting on a paper each hit and velocity.
You will see a sweet spot emerge where all rounds stay tight in a certain charge range. Everything outside this range will be all over in comparison.
From there just pick the middle charge weight in this range and a forgiving load is found.
Another bullet will likely shoot better rather than another powder if not satisfied at that point, I've been told. Pick your powder and find your bullet so to speak.
If you cannot find a good load with a couple good bullets like this right away you probably need a new barrel is said.
Also, clean first then foul the barrel with that powder being tested for 3 to 5 rounds before starting.
Development test would be done at 200yds, 300 if no wind was present.
In your first test, cases firing rounds #1,8,11,16,19,22,29 and 31 are suspect and would be marked and set aside for later checking of case capacity due to the velocity variation within the load fired and use the other cases for the next test.
The one you mention that was always "off" could likely be resolved here too.
I've heard that CCI BR2 primers solved many flier issues for quite a few people on another site. I switched to them from the GM210M's the last brick I bought but can't say yet if they changed because I haven't hot a known load with them yet.
Sorry about the long post.
It sounds like yours will be a real shooter with very little effort though.