Originally Posted by Parkerb14
I am planning on running a 20MOA base, and a NF 50mm. I want to know what NF ring height I should get so the objective is close to the barrel?
What is so important about having the scope's objective close to the barrel? It does matter some but can have disadvantages either higher or lower.
What is important is to have your eye comfortably centered behind the scope when you have a stable and comfortable "cheek weld" with the stock, your face, and (usually) the cup between the thumb and forefinger of your shooting hand. The latter depends on the stock design and your shoting style. Having that allows you to rapidly shoulder the rifle and everything will be in place just by feel. Achieving that of course depends on the comb of your rifle's stock and the dimensions of your face. Use what ever ring height gives that that fit If the the scope is way too high or so low it hits the barrel under recoil you may want to modify or change the stock.
You cannot shoot accurately with your face smashed against the stock trying to look though a scope that's too low or with your head bobbing around in the air not touching the stock because the scope is too high. It has to fit YOUR face. No one can tell you the proper ring height without having you and your rifle present.
I have several cheap sets of rings I use just to test what ring height fits my face when I mount a scope on a rifle. That doesn't mean a new scope or new rifle, just changing something. Vertically split rings with only two screws make the job quick and easy. I don't shoot the rifle with those rings place. They're just to get measurements.
You did tell us the model of the BRAND of the scope and the wedge of the base
You did NOT tell us:
The make and model of your rifle
The contour of the barrel vs distance from the receiver
The height of the top of the rail above the centerline of the receiver.
The contour of the comb of the stock in three dimensions relative to the center line of the receiver.
That still leaves the length of pull of the receiver an where that will comfortalby place the entrance pupil of your eye relative to the receiver. The position of the scope along a line parallel to the bore matters too. There are practical concerns such as whether you'll have proper clearance to operate the bolt if it's a bolt action, or the charging handle for an AR.
It doesn't matter though that you didn't provide the above info. We still don't know the dimensions of your face and I doubt anyone here would try to calculate the correct height rings if you did.
It's foolish to buy expensive rings before you you have the rest of the major components (stock, scope, action, and barrel) in hand and assembled. You might want to even wait on buying the rail until you have an idea what scope height you'll end up with. Also the fit of your face between the stocks comb and your eye's centerline changes some whether you're shooting prone or standing. Adjustable combs aren't common on hunting rifles, but they make sense for "longrangehunting"
Fitting rings is a job you really should do yourself. It's time consuming but not difficult. You need to test the rifle from various positions and hold the scope on targets at distances and angles you expect to encounter. If it's not comfortable for you it's not right. You can' leave the rifle with a gunsmith and expect the job to be done to fit you, not to mention most charge by the hour.