Looks like the 27.5 suits your rifle too, but I agree that you should wait for a still day and try again, because taking those results as gospel could send you down the wrong path early.
Once you've satisfied yourself of the load, start mucking about with the bullet seating depth. Get yourself a OAL gauge from Hornady and measure the distance between the bolt face and the lands. Using your pet powder weight, start loading different lengths and see where you go with that.
I once read an article by a top reloader. I stand to be corrected on this but it could have been Bruce Potts. He de