@Kyson Spencer, first welcome to THR! Second, here’s hoping you own calipers! Manufacturers do indeed measure differently so you’ll first need to determine how they do it. Many offer more information on those specifics at their site and sometimes retailers can provide the info online.
If you have your scope handy, you’ll need 2 measurements minimum; the objective diameter OD (not the stated lens diameter) and tube diameter, usually 1” or 30mm. Remember there may be other factors such as bolt handle lift that can interfere with a scope mounted too low before proceeding.
As an example, if you have a “x44mm” adjustable objective, you may find its OD closer to 50mm. Half will sit below the center of the scope rings’ centerline but first you must discount the tube diameter. 50mm - 30mm = 20mm. 1/2 of that 20mm or 10mm is what must clear the barrel/receiver.
If you’ve added a 1-piece rail that measures 4mm thickness, then, all other considerations aside (see previous paragraph’s warning), you will need 30mm scope rings (to match your main tube diameter) that are a minimum of 22mm to their centerline for absolute minimal clearance.
NOW, for your specific scope: objective diameter is 2.01”, main tube is 30mm (1.181”), so:
2.01 - 1.181 = .829
.829/2 = .4145” or just under a 1/2” for easy math and breathing room. You’ll need to measure the thickness of your EGW base and subtract it from that thickness, then decide if you’ll be wanting scope covers that might add to the equation before finalizing things.
I also prefer to mock up with shim material, wood, cardboard, whatever, placed between scope and rail then taped lightly into position to check for bolt interference, including removing the bolt.
Best of luck and my apologies for the long explanation.
