It's not that the sizing die, or the expander "isn't doing its job". Its that they are, but are not the right size for the bullet you are using.
To further complicate things you expanded the inside too much, FOR THE BULLET YOU HAD.
Here are the measurements. Bullet is .452 like it should be.
Fine there.
The resized case mouth inside diameter is .452.
Not so fine. Can work with light loads but not enough neck tension for heavier recoiling loads
The outside is .473. On the outside diameter my manual says it should be .480.
Misunderstanding. .480" is not the diameter it
should be. .480" is the max diameter it is
allowed to be. Unless the drawing states otherwise, the dimensions given on case drawings are the max allowed amounts. These numbers (all of them) are not what the case has to be, its what the case cannot exceed.
I flared the inside of the case mouth to .454 (didn’t take picture of this measurement.)
How much you flare usually isn't an issue what matter is how far down the expansion goes.
Also, under the right conditions, an improper crimp can loosen the grip of the case on the bullet, except where the crimp actually touches.
A bullet that spins in the case is TOO LOOSE. Whether the result of an error or simply a case of stacking tolerances unknown until the round is completed, tis' too loose a fit for good performance.
Before WWII the "standard" bore diameter of the .45 Colt was .454" After WWII, due to the increasing numbers of dual cylinder revolvers shooting .45acp, bore diameters were reduced to the .451/.452 more useful when shooting ACP bullets. The larger .454 lead slugs squeeze down that tiny bit just fine, without issue.
Die sets CAN be found with both size expanders. Have you measured the expander in your set? A .454" expander (and neither size is the bullet diameter they are a couple thousandths smaller, or should be) is oversize for loading .452" bullets.
Call Hornady, explain what's going on, give them the actual measured diameters if asked, and see what they say. My guess is your expander is too big for the bullets used.