Just started my second year of USPSA. Looking to make some major matchs this year so I want to make sure my load is correct. Went to the range today to chrono some rounds. Precision delta 200 gr FMJ, 4.2gr Titegroup , oal 1.18 out of Fusion 6in. It was making between 166 and 168 power factor. My question is the temps were about 40 degrees or colder outside. How will this effect the #s ? How much of a buffer should tune the round up to ?