My first rifle when I started getting back into shooting after a twenty year break was a Garand.....
but when I started getting into it, like
@Srikaleak seems to be doing, I did similar putting a bunch of money on an LMT with an S&B.
If you like this sport starting with that high end AR almost guarantees a future $5 - $7K purchase of a custom bolt gun/scope setup of some sort.
Okay here is some further theory to maybe help Srikaleak out or for me to step on my dick again....
@Srikaleak understand this now, imprint it in your brain, and just know it is natural law like a revolving earth brings night and day..........a bullet does not rise when it leaves the muzzle of your rifle/pistol. There is no aerodynamic lift or whatever someone wants to imagine it. A bullet is not a wing.
This kind of ties into my F - up regarding "a couple inches low" comment. So lets explain that so you know what that was about.
First know in your mind that it is a fact that from a perfectly level muzzle the elevation of the bullet in flight can only decrease from the point of the muzzle. The only "rise" of the bullet will result from the angle you input on your bore.
So I suggest a 25 yard initial sight in. Why 25 yards?
A. The amount of error is 1/4 what it would be at 100 yards. So if your scope is off 4 inches at 25 yards you should still be "on" a target 12"x12" wide but at 100 yards you would be off 16" and not see the shot on your paper to adjust from. Usually with a new scope the error is greater and at 100 yards unless someone is spotting the berm for you you have no idea where to adjust to.
B. A 25 yard zero has a correlation with a 200 yard zero with the cartridges I am familiar with - 5.56, .308, 30-06 - and I assume others. A "zero" represents the point where the flight of the bullet determined by the angle of elevation on your barrel and the line of your sighting device intersect.
So your sight system looks on a straight line to your point of aim while your muzzle is pointed in the direction of the target at some angle necessary to get the bullet to travel the desired distance. Where the straight sight line and the angled muzzle line intersect is ideally your desired point of impact but no it never is when you put a new scope on a new rifle as you are doing until you adjust the scope reticle to align with the bore/bullet path of flight.
So you take your first 25 yard shot and you see your shot is 2 inches higher than your point of aim and 3.5 inches right.
You tried holding the rifle steady and moving your reticle cross hair over onto the shot hole. I do this with scopes that have turrets that really have no reference or the crosshairs are standard crosshairs. It works great but during a solo session its kind of a pain holding the rifle steady and manipulating what are typically coin slot adjusters in that type of scope.
You have a NightForce with I assume some sort of MOA or MilDot reticle so you can measure the correction using your reticle reference.
If you are using a Milliradian based scope measure how many mils are represented by 2 inches high and 3.5 inches right. Looking through your scope you can measure approximately +/-.4 mil high and .9 mil right. Adjust your turrets - down .4 mil and left +/-.9 mil - than take your next shot hopefully showing POA/POI agree after doing so.
So now why does this help at 100 yards and what happens to the bullet after it passes through the paper at 25 yards.
At 25 yards the bullet intersects across line of sight and due to the angle you have imparted on your muzzle the bullet is now above your line of sight. Gravity is acting upon the bullet fighting velocity and angle of departure forcing that bullet to come back to earth. At some point gravity defeats velocity/angle and it reaches its Apex/Max ordinate and begins to return to earth.
At some point the bullet will again cross your straight line of sight. That point for my cartridges is 200 yards down range.
Getting in the weeds here you may not want to read this paragraph- Im not sure, smarter guys will hopefully chime in, but I think this is a constant of sorts. Projectiles may have different velocities and require different angles of departure to reach certain distances but the effect of gravity is constant and rates of fall are consistent. I dont totally understand it what relation makes this little snippet true but there is a proof of this exhibited by showing that if you drop a bullet from your hand and fire a bullet from a rifle, the time in the air from drop and time in flight from muzzle to return to earth are equal. Im guessing the timing of the two falls would need to occur at max ordinate. I also recall the exhibit in my local science museum I saw as a kid of a feather in one tall vacuum tube and a bowling ball in an adjacent tall vacuum tube both being dropped and landing at the same time - gravity always wins and effects everything equally assuming environmental variances are removed.
Back on track...
So your bullet departed over your line of sight at 25 yards and it returns to your line of sight at 200 yards.
The typical change in zero from 100 yards to 200 yards is +/- 2 MOA. So at 100 yards your 25 yard initial zero will equate to using a 200 yard zero at 100 yards which should provide impacts on target 2 inches HIGHER than your point of aim (remember bullets always fall and you have to impart angle on the muzzle to reach 200 yards). If you measure it with your Mil reticle it will show about +/-.4 mil higher.
So using a suitable sized sight in target and with the ability to hit POA at 25 yards you should be within two inches HIGHER of where you want to be at 100 yards.
You would be much better hearing this in the online training Lowlight provides or a local class though because what I gave you above is based on what my rifles tend to exhibit and any errors in reading/notetaking I made while learning it......as well I could be a 650 pound troll wearing an oxygen mask in my Moms basement, all Incel like, just spouting shit to hope someone hits "like" to impart a value to having taken the effort to wake up and don dirty sweatpants after rubbing one out into my yellowed sheets..........but I digress.
PS - I dont often think of this shit. Thank you in your newness for making me ponder what I probably take for granted and due to familiarity look on with contempt - at my peril.