Gunner,
First, I have to say I like your covered lap pool. That must come in handy during the summers in Texas. Second, nice hardware! Your leveling vise is really nice. I'm envious. The leveling vise I put together is lame by comparison (but it breaks down into pieces small enough to fit in my portable tool box). That said, your video leaves me with more questions than answers.
Yes it is hot here. It is a very nice piece of equipment. It arrives complete with ground glass ocular level, bearing surface bars and the weighted plumb line. If you want one it can be ordered by emailing [email protected]
I'm not clear what the purpose is of leveling the receiver races. You're not attaching an anti-cant indicator to the receiver, so why does this even matter? Your video emphasizes the high sensitivity of the spirit level. Can you explain why that alignment step is so important?
Once rifle and scope are aligned you can mount an anti cant to either receiver or scope. I'll have to do another video however to demonstrate why this matters so much. It'll be later this week.
Based on the scopes I've inspected, I'm confident that most scope manufacturers don't align the reticle to the turret axis with that level of precision. What's the point of aligning the reticle to a plumb line so precisely, when getting the turret axis plumb is really the goal?
Most do but non the less the reticle should be plumbed to gravity for true accurate alignment. Not turret tops level.
Finally, you say that 30 MOA is not precise enough for 1,000 yds and beyond. I guess that depends on the type of shooting you're doing. For most long-range hunting calibers the aiming error for 1 degree of scope cant at 1,000 yards is only a few inches - even less at high altitude. Scope alignment to within 30 MOA has been adequate in my experience. Target shooting may be a different situation because bullets only have to be supersonic - they don't need to carry enough energy to kill game. But if you're target shooting with a bipod, why would you be concerned about rifle cant? Doesn't the bipod hold the rifle at the same cant angle on every shot? What type of shooting are you doing that needs such highly precise reticle alignment?
Scope/ rifle cant is an insidious killer of accuracy which at long ranges become big misses. At 1000 yards 1 MOA = 10 inches and 1 MIL = 36 inches. Also isn't the purpose of any scope installing tool to eliminate cant to some degree? Article here worth reading Cant Errors - Long range shooting
Also, I'm not clear how you would reduce scope canting errors to substantially less than 30 MOA in the field. You would need a ground glass spirit level attached to the rifle, and a precisely adjustable bipod. While I wouldn't be surprised to learn that you have them, that's not the type of equipment most long range shooters would have on a hunting trip. Again, what's the point of doing the alignment to 1 MOA if you can only hold to within 30 MOA (15 MOA on a really good day)?
If you already have cant introduced into your rifle before you get to the field you simply amplify this issue. Eliminate it from your rig then it's up to the shooter to determine taking a lever shot.
That said, the particular rifle you are using in the video has Warne-type rings, which are split down the middle and are left-right symmetric. Assuming the rings are mounted on your Mauser action without any offset, aligning both the scope and receiver to be level will likely result in a properly aligned turret axis. That is a rare situation in my experience, because Warne rings are not very common.