Recently picked up a Kimber Montana in 280 Ackley Improved and the seller was kind enough to include some factory Nosler 140gr Accubond ammo. I primarily reload so I decided to use some of those rounds to zero the scope and then use the brass rather than buying some new stuff. Accuracy was much worse than I would have expected (even with the pencil barrel). I only shot two three shot groups and they were both 1.25 and 1.50 MOA. The 6.5cm that I was also sighting in was shooting .3-.4 MOA so I know it wasn't my shooting so I was pretty bummed to say the least. I decided not to waste the rest of the ammo and go home and pull the factory rounds down for components. I was shocked to see the deviation in powder weights as I pulled each projectile and weighed the powder on every round. Out of the 14 rounds that I pulled 61.8 grains of whatever powder they were using was the most common drop but there were some that were +/- .4 grains and one even a full 1.0 grain lower than the rest.
I'm hoping that after working up a load for this rifle the groups will tighten up and it was just an issue of being factory ammo. It's been a while since I've shot factory stuff but it was a good reminder why I take the time to reload for all of my firearms.