There just isn't a lot of room in a 25-45 for 117's, your pretty much lobbing them out there about on par with a 25-35 Win.
I shoot a 25-204 1-10 twist and I don't have enough room for 117's. 85gr NBT's are great at around 3000 fps, 21" barrel. 75gr V-max at 3150 fps and 100 gr Partitions at 2800 and change.
Usually if a rifle doesn't like a bullet you aren't going to get 4 good shots and a flyer then a poor group and back to good group and a flyer. Have you checked to see if the gas block is hitting the handguard.
Shoot 3 shot groups and everything will be just fine, the barrel might be heating enough to throw that last one.
The only shot that really counts is the first one from a cold barrel.