Help me understand a flyer

[L.Sherm]

I went back and looked at your groups again, I guess some are good with 2" of vertical at 100 that's alot.
First I would switch primers and try that if that doesnt work single load and get .010 off if that doesnt work switch powders and start over with another powder, primer combo.

 

[NewLRhunter]

So are y'all saying the 1 shot at .3 grain increments ladder test is not what I should be doing for load development for a 308 that I'm only going to be taking hunting shots at 500 yards or less? Because your right, I won't be shooting any deer past 500 with a 308 just not enough umph behind it at that range imo.

A single shot ladder test can really lead you down the wrong road in a hurry. IMO it might help a lot if you do your initial load spread with groups of 5 or 6 shots and spacing of around 0.5grs (I've tried groups of 3 and 4 and been bitten too many times thinking I was onto a good load only to find out later that that particular group of 3 or 4 was just luck). Single shot ladders can rule out bad areas in the powder weight spectrum but can easily give you false positives. Shooting groups of 5 or 6 eats up components a bit faster, but I've found that it prevents a lot of frustration like what you're seeing with those "flyers" on small groups. Those might not be flyers at all but could actually represent the group size that one could expect with that load combination if you fired a larger number of shots.

Here is a rough illustration. Say you fired three powder charges and this is how the groupings turned out.

In another scenario, let's say you chose to only fire single shot ladder tests with those same 3 charges and the shots with the yellow centers (in the figure below) represent the single shots that you were able to get data from. From that small sample size you might be drawn to believe that the Blue and Red groups' powder charges should fall very close to each other in a "node" and that this is the charge weight to focus around. When in reality if you had fired a larger group for each powder charge and used the avg point of impact it would have been clear that the Green and Red groups were much closer to each other and a better choice.

Then go back and do another spread between the Green and Red and pick your final powder charge.

After settling on a powder charge to use go back and vary seating depth with that final charge weight you picked and shoot them on paper at 200 or 300 yds if you can. You'll likely find one group that is a winner. (I try to do my initial testing with the bullet seated close to the lands and/or as long as your rifle's magazine will allow...then after a powder charge is chosen go back and load that powder charge with 4 or 5 different (shorter) seating depths.)

As a last step go back and load 10rds of this final load and shoot it to ensure there are no surprises.

 

[Zymurgist]

I am running 43.5 gr of Varget in my rem 308 that's what it likes but then that's mine not yours . I also have the bullet seated .062 from the lands .

My M1a loves 43.5g of IMR4064 under a 168gr AMAX. I even load it in Lake City brass to stay true to the GI loading.