so doing the math I'm getting that the bullet should travel 900 yards in a second, does that sound right?
Probably quite a bit less than that. I would guess some where around 600 yards in a second.
Why?
The 180 gr bullet is doing 2625 fps at the muzzle, but is slowing down continuously due to air resistance. At 100 yards it is only going 2,300 fps. By the time it gets out to 500 yards it is only going half that speed. By the time you get out to 1,000 yards it's slowed down to under 850 fps.
Here's how I get 600 yards.
If you use Hornady's ballistic calculator
Hornady you can punch in the bullet weight, 180 gr, the Ballsictic Coeficient ,267 (from Wnchesters web site) and the muzzle velocity of 2625 and it will give you a nice chart with the velocities and energy out to 1,000 yards.
Now the bullet is traveling 2625 fps at the muzzle and only 2303 at 100 yards. So from 0-100 yards it is averaging 2,463 fps. At 2,463 FPS it will take the bullet .122 of a second to travel 100 yards (300 feet divided by 2,463) Continue taking the average speed for each 100 yards, figure the time needed to travel that 100 yards, and start adding them up until you get to 1.0 seconds.
It also seems to work if you take the velocity at the muzzle (2,625 fps) and the velocity at 600 yards (1,128 fps), add them and divide by 2 to get the average velocity across the 600 yards. You get 1,876 fps. There are 1,800 feet in 600 yards.