Yes, I shot the P-10C with open sights today too, but my eyesight didn't cooperate, so I don't have any 6" groups to show for the P-10C.  I got out my bullseye pistol and shot it at 100, and, like every time I've shot the 97 at this distance, I had good results.  Red dot helped!  This pistol has the excellent CGW 1911 style barrel bushing installed.  The trigger pull is completely different from a P-10C.  Not that there is anything wrong with the P-10C trigger.  

https://youtu.be/u7Rp9RLx3QE

Joe

....just watched your video - that's pretty cool!

How can you see the target at that distance?

I use a 3 moa dot on a Burris Fast Fire 3, and the dot is good and crisp.  I also have had cataract surgery so my vision at distance is quite good.  

But here is how I get the holdover right.  The B-8C timed fire bullseye target has the perfect size circle black bullseye to use as an aimpoint for the 3 moa dot at 100 yards.  So I put a clean fresh target near the top of the target frame and go back to the table and fire off five rounds, very carefully.  Then I go back to the target and see where the group is.  In this case, the group was something like 18" below the aim point.  Then I put up a fresh target with the bullseye covering the first group, turn on the cameras and go back and shoot a group.  If nothing has changed, the new group will hit exactly in the center of the targeted bullseye, stapled below the aim point.  This way, I don't have to change the zero on the sight from my standing, single hand 25 yard bullseye match zero.  I never touch the sight adjustments.  I will hold for wind but, on a very gusty day, I'm not going to attempt this anyway.  

Joe