Allllllrighty, my Hornady Chamber Length gage and comparator have arrived and I finally have time to play around. Here's what I found.

Hornady Case = 2.007"
Comparator Gage Length = 1.005"

Out of 10 attempts, my averaged Chamber Length is
Base to Ogive = 2.3694"

After seating a bullet to that length and measuring:
Base to Tip (168gr SMK) = 2.949"

This makes sense, because I was measuring it at 2.950-2.952" before, but now I am more confident in the value.

So, I went back and measured/recorded all values for my remaining 51 rounds.
Average Base to Ogive = 2.2195"

2.3694" - 2.2195" = 0.1499"
2.949" - 0.1499" = 2.7991"

Which means my bullets are all seated to 2.799" (averaged) which is what I was aiming for before.

Now, with all of this in mind, I need to decide if I can seat a Sierra 168gr MatchKing to a length of 2.949" - 0.005" (0.005" off the lands) for a length of 2.944" or 2.364" (base to ogive) with my new Lapua brass. I still haven't tracked down any CCI #200 primers locally so I might try this again with the WLR primers and see if I get the same issues (only changing the brass and COAL).

After doing some math (can show work if needed/interested), I have found the bearing surface of the Sierra 168gr MatchKing bullet to be 0.500" ogive-to-ogive.

Tip of bullet to base ogive = 1.078"
Base of bullet to tip ogive = 0.632"
OAL of Bullet = 1.210"

1.210" - 1.078" = Base of bullet below base ogive = 0.132"
1.210" - 0.632" = Bullet above tip ogive = 0.578"
1.210" - 0.132" - 0.578" = 0.500"

So, my target OAL length (base to ogive) is 2.364"
Hornady Tool Case Length = 2.007"
Exposed bullet bearing surface (between ogive to ogive on bullet) = 2.364" - 2.007" = 0.357"
Therefore, my contact of brass to bullet = 0.500" - 0.357" = 0.143"
And finding the percentage = 0.143/0.500 = 0.286 = 28.6% contact.

This is less than the recalled value of 33% minimum contact surface between bullet to brass. The 33% value would mean my round OAL is
(.33/2) / 0.5 = 0.165
0.165" - 0.143" = 0.022"
0.022" + 0.005" = 0.027" away from the lands
2.949" - 0.027" = 2.922" COAL with Sierra 168gr MatchKing.

Alright, so that seems EXTREMELY long. I already know it won't fit into my rifles internal hinged floorplate magazine. But, is there a reason I should NOT load my next rounds to this length of 2.922"? I need to verify that the bullet to brass contact should be a minimum of 33% of the length of the bullet's bearing surface.

It looks like the AICS magazine max COAL length is 2.880". Since I plan to add a DBM at some point that uses AICS mags, should I load these rounds to 2.875", giving me a total of 0.074" away from the lands and 0.005" shorter than magazine max COAL?

Yes. I am probably overthinking this A TON! However, I want to make sure I don't have any more problems like that other time, even if as some of you said, I was seeing over pressure signs in my 42.0+ charges, even though it isn't the conventional primer cratering as I understand it.