I have a Remington 700 PSS in .223. This rifle shoots well under 1/2 MOA with 52 grain SMK. I checked the twist with a cleaning rod and it shakes out to 1 in 12". I thought that all remington 700 PSS .223s were 1 in 9 twist? The serial number is D6850XXX. The only other thing that is different about it is the parkerizing. It has a greenish color vs the black of my other PSS rifles. Is the 1 in 12" twist something that is common? I was going to try heavier bullets in this rifle, but am not going to waste my time since it is a 1 in 12 twist. Any info is appreciated.