Why are gun scope/sight reticles normally red in color?

SOURCE: Sighting in my scope

That should be covered in your manual.

If not, give Nikon a call.

Or, repost your question on a Bulletin Borad such as at SWFA, where another user may have the identical scope.

SOURCE: scope won't sight in

Yes, rim fire scopes can't be used on a stronger firearm as the recoil will alter the internal mechanism. I fought with scopes of all types for years until I bought a used Leopold, never finding a better one! Hope you can find one of those.

SOURCE: how to sight scope in /what scope do i have ?

Real simple Scott.
You can 'Zero' your scope/rifle even if you don't have a laser bore-scope device.
All this is assuming that your used rifle has not had the barrel shot out and that the head-space is still within specs for that rifle. Have all this checked by a gunsmith first. You can dress up a piece of poop and it will be pretty, but still be poop. Make sure yours isn't to begin with. As for the scope, it's hard to tell unless there's obvious damage or it's an antique past it's prime. Try to get as good a quality scope as possible to start with. You would not put one ply tube tires on your mustang and expect to get the best performance, so...
Most rifles are capable of shooting quite accurately, and all things being equal, it's the shooters job of making it happen.
Ammunition should be considered as well. Toss your old military ball ammo and junk from overseas, both of'em. If you want to shoot accurately and consistently, you must spend the bucks for the best ammo you can afford.
You MUST KNOW what the BALLISTICS are for the Cal./type/weight ammo you will be shooting and the corresponding distance it will be shot from.

Make sure your rifle is CLEAN inside and out. A clean rifle is a happy rifle.
Make sure that your rifle 'fits' your body's frame and that you are familiar and practice good rifle shooting techniques.
'Zeroing' is best done from the prone position as that is the most steady position to shoot from.
Do you have a bi-pod attached? Whether you do or not, sandbag your rifle securely but still able to make small adjustments to the rifle position itself.
Set up a target with a 1" black dot at 50rds.
Remove the bolt.
Lay down with your rifle but stay OFF of it, touch it as little as possible at this point.
With out disturbing the rifle look through the bore downrange to your target. Locate the black dot and if necessary adjust your rifle from the **** end until you can see the dot through the bore. Keep making minor adjustments until the dot appears to be centered in the bore. Make sure rifle is secure and steady at this point.
Then without moving or touching the rifle, look through the scope using the correct eye relief distance and locate the black dot. Now using the Vertical(Elevation) and Horizontal(Windage) adjustment knobs, move the reticles(crosshairs) until they both are centered on the dot.
Again look through the bore to make sure that you have not moved the rifle and that the dot is still centered in the bore. If not, adjust the rifle again to center the dot, then go back to the scope and adjust as necessary to move the RETICLES to the center of the dot. It may be necessary to repeat this a few times before you have achieved this particular goal.
You do not mention brand/model of your scope. It probably adjusts the reticle or crosshairs in 1/4minute increments (1/4 inch increments with each individual click movement of the turret knobs at 100 yard distance). IT IS CRITICAL for you to know how your own scope adjusts.
Now, bolt back in and load 3 rounds of quality ammo.
You are going to shoot 3 rounds in succession without getting off the rifle or making any adjustments to the rifle or scope. You are looking for a 3 shot group to determine a rough average of how far and where the rounds are impacting initially. Use good shooting techniques, breath control, relax, sight picture, squeeeeeeze the trigger, follow through the scope, there is no need to take your eye off the scope while doing this, hold your shooting position for all 3 shots.
You will now have to make adjustments of the scope unless you are hitting the black dot already which is quite possible.
Remember that if your scope is a 1/4" adjustment at 100yds, it means that for each 'click' that you adjust either Vertically or Horizontally at 100rds, the reticle/crosshairs will move accordingly 1/4 of an inch Vertically or Horizontally. At 200yds, one click will move it 1/2 inch, at 300yrd it will move it 3/4 of an inch, at 400yrd, it will be 1 inch.
Right now you are at 50yrds distance from your target. Each click from here will move the RETICLES about 1/8 of an inch so estimate the distance that your most central shot of the 3 you fired, is from the black dot and adjust accordingly. You're not moving the RIFLE here, you are simply moving the scope RETICLES so that your point of aim and point of impact coincides.
Now load 3 more rounds of ammo and repeat as above. You should only have to use about 9 rounds to get on target, the black dot.
Once you are hitting the black dot at the 50yrd line, move back to the 100yrd line. Put a fresh black dot on your target and repeat the steps from above. Your first 3 shots from the 100yrd line should be about 1/2 to 1 inch low. Don't follow the bullet strikes! Keep your point of aim and the crosshairs ON the black dot no matter where the bullets are striking on the target. Remember, now at 100yrds your RETICLES will move 1/4inch with each 'click' of adjustment of the turret knobs.
Adjust the scope as needed at this point. Once you are 'ON TARGET'(hitting the black dot), you now have your 100yrd. 'ZERO'.
Now that you have this 100yrd ZERO, you must loosen the turret knobs , both the Vertical(Elevation) and the Horizontal(Windage) turrets and align the '0' on the knobs with the '0' on the scope at the base of each knob. Now tighten the set screws and you are set to go. If you want to know your 200yrd 'ZERO', simply move back to the 200yrd line, your 'come-up' or elevation adjustment should be about 7-9 clicks, at least for .308 168grn HPBT, but you will figure it out for the Cal./brand/wght ammo you are using. WHATEVER the 'come-up' you need to make at 200, 300,400yrds or wherever, be sure to make note of the number of clicks you used to find the Zero for that distance. Use a fine point endelible marker and actually write the ZERO info on thestock of your rifle. You don't need to mark anything for the 100yrd ZERO, it's a given already. Write; 200/9, 300/18 and so on. You should also get your ZERO for the intermidiate, 150yrd, 250yrds etc, distances as well.
Remember that weather conditions, source and intesity of light conditions, your own body condition at any particular moment or day can have an affecf on how you and/or your rifle shoot. Good luck.

SOURCE: what is the procedure for sighting a zeiss z-plex

mount it, get a 100 yard target, and you have to chase the bullet right is left up is down

SOURCE: I have a Beeman RS1 air rifle,the gun shoots 12

look at the scope rings, see if they are mis-mounted or mis-matched.