Dillon gauge with a 223, but Wilson gauges work the same way.
You want the end of the case to be below the end of the gauge, but above the cut. Like in the pic.
How to do the visual check for the above, hold gauge at about a 45 degree angle away from you.
In the above pic you would look above the + in the case. What you should see is a sliver of silver above the end of the case.
No sliver, case is high and not sized enough.
If the end of the case is below the cut, it's easy to see.
I use the same "sliver" method to check for high primers. See the case the pistol barrel is pointing to..
You can see a sliver of brass above the primer.
Which means the primer is below the case head like you want.
When you are ready to take your 300 blk loads to the next level, then you can get into annealing.
I will try to work up a budget annealing thread this weekend, as it still in my head and not posted yet.
So no link.