I think the front looks fine, though it could be the angle... a minor cant (one needing calipers to detect) probably wouldn't put you off the paper at 25. If it doesn't stand out to the eye, it's probably not an issue. Still, worth being sure, since you're troubleshooting now.
I guess it could be the rear sight/receiver itself is off a bit, but then again, it seems like that too would jump out without even having to check.
If that too checks out, then I would really look hard at the barrel... I mean, that's really all that's left.