Tuukka-
Neither I, or the rifle can produce the .25 MOA results consistantly. There's too many variables (wind, operator error, etc.). The fact is, if you work with your handloads enough you can make an AR15, especially one with a precision stainless barrel flat shoot.
My rifle seems to like 25.0 gr. of VihtaVuori N135 with the bullet seated at 2.245 the best. In ten separate five shot group tests at 100 yards, this load averaged .558 MOA. Three of these groups were at .25 MOA or slightly smaller.
Another .25 MOA group was shot with 26.0 gr. of Varget, with the bullet again seated at 2.245. Ten five shot groups were also measured with this load, but averaged .680 MOA.
The last .25 MOA group I will tell you about was shot with 24.0 gr. of VihtaVuori N133 also seated at 2.245. Eleven five shot groups were measured and averaged .667 MOA.
All groups were shot from a bench rest, using a 4-12x40mm scope. All cartidges were loaded on a Dillon RL550B.
So nope, I'm not pulling your leg. I'm just reporting the success I've had in testing my handloads with the 53gr. Sierra HP.