Hey guys! I am new to this forum but after some issues my dad and I had at the range today I figured this would be a good source of information. I bought a remington 700 sendaro 308 with an aftermarket stock that had 1 box of shells through it according to the previous owner. I'll mention that it had a 6.5 lb trigger pull so I brought it in and had it lowered to less than 3. I brought it to the range and after probably 5-10 shots to get it zeroed I was shooting pretty good groups (smallest was .7 from 100) with some of our hand loads we use in other 308s (150 grain SSTs with 47 grains of H414 using Hornady brass). My dad and I loaded up some new loads (150 Hornady ssts on 48 grains of H380) and cleaned my rifle as well. We went to the range and right off the bat my rifle was really struggling. I'm talking like 3-4 inch groups at 100 off a bench. After about 15 or 20 out of no where it shot a group that could be covered by a quarter. We decided to walk down and check it out and when we got back I shot another group. It was about 2 inches on a cooled down barrel (it topped out at 5 degrees here in SD today). My next group I shot could be covered with a quarter again! By this time we used up all of hand loads so we headed home in a state of confusion. I know we havent done any load development or even sized the cartriges to my rifle but I was wondering if u guys had any thoughts on the situation? Was shooting on an unfowled barrel our probelm? Does the hot and cold barrel make that much of a diffrence? Or do u think my rifle just doesn't like the current load? Any and all advice is appreciated!