Ok So I wrote an Optics FAQ awhile back and posted it on
Kiwi Hunters - Home and figure it would also help answer some questions around here so here it be:
Q: What is the best scope to get for under (insert cost here)?
A: The quality of rifle scopes is usually in direct relation to price.The best choice is to buy the very best scope you can afford, instead of buying a poor quality scope and quickly ditching it for the one you really wanted to begin with. If you absolutely can't afford a top quality scope, see the next question.
Q: OK, I can't possibly afford a top quality scope. Should I abandon hope?
A: No, there are several quality scopes available at lower price points. Leupold's Mark 2 series and SWFA's Super Sniper line are two of the better known "budget" optics.
Q: Wow! I really like the new (insert brand name) scope with the huge objective lense, illuminated reticule,mil-dots etc. With features like these, it must be good! Cheap too.
A: Beware cheap scopes with a long list of features. Chances are the quality of the lenses are poor, and the company is hoping you won't notice while you stare into the gaping maw of the monstrous objective(front) lense. Quality of glass is far more important than size of glass. A top quality 40mm objective scope will be brighter and clearer than a cheap 55mm space scope. Again, buy the best you can afford, and suspect any cheap scope with fancy features.
Q: What features should I look for in a scope?
A: A good scope should have repeatable adjustments, high quality glass,ample elevation travel and be durable. Other nice features are tall"target" turrets, a measuring/range finding reticule, illuminated reticule and an first focal plane reticule.
Q: What's a turret?
A: Turrets are the rotating dials on the scope body. Turret types include elevation (impact up/down), windage (impact left/right),parallax, and reticule illumination. Elevation and windage turrets most commonly have 1/4 MOA "click" values, but other values are available,including 1/8, 1/2, 1/3, and 1 MOA. Turrets can also be had with metric measurements for those who want them.
Q: What's a MOA?
A: MOA is an abbreviation for Minute of Angle, a mathematical concept involving degrees in a circle. For our purposes, MOA roughly corresponds to 1 inch at 100 yards, 2 inches a 200, 3 at 300, and soon. This is called "shooter's MOA". So, if a scope has 1/4 MOA "clicks"it will take 4 clicks to move the bullet impact one inch in the desired direction at 100 yards.
Q: How much magnification do I need?
A: How much magnification you really need depends on the intended application for your rifle. If your shooting will be at fixed targets at known distance on the range only (as in long range competition) then the sky is the limit. If you plan to use the rifle for hunting,engaging moving targets at a shooting school, or for "Tactical"competitions, you should consider having a scope with a lower power.The higher the power, the more restricted the field of view, the worse mirage gets, the lower the total elevation travel will be, and so on.Some believe that a good rule of thumb is 1x magnification per 100yards, other prefer a little more. Look, think, and decide for yourself.
Q: What is field of view?
A: FOV, or field of view, is the amount of the surroundings you can see when looking through a scope at a certain power at a certain distance.A wide FOV is important when engaging non-static targets, who might move right out of your scope picture before you can shoot. That is, if you can even find the target in the first place with your Hubble sized,super-duper 40x magnification scope while searching for your target.Lower power corresponds to wider FOV, generally a good thing, and higher power corresponds to less.
Q: Money is no object, who makes the best scopes?
A: This is very much a matter of opinion. All of the big name makers make excellent scopes in their flagship lines, and the choice becomes simply which features you want more. Two companies particularly well known for best-quality scopes (and the attendant prices) are U.S.Optics and Schmidt and Bender. U.S. Optics will even custom build a scope to your desires. Leupold Mark 4s and Nightforce NXS scopes are also popular.
Q: What the heck is a BDC?
A: A Bullet Drop Compensator, or BDC, is a feature that allows you to simply dial the range to target and engage. BDCs are typically represented by a second set of numbers on the elevation turret above the MOA marks, (1,2,3, etc...) designating hundreds of yards. A BDC will only be accurate under the exact conditions that it was calibrated; that is, the same bullet, muzzle velocity, elevation above sea level, humidity, temperature etc.
Q: What is this stuff about focal planes?
A: This has to do with the position of the reticule inside the scope.Reticules on the first focal plane (FFP) will change size with the magnification, and allow range finding reticules to give accurate measurements at any magnification. Second focal plane (SFP) reticules stay a constant size at any magnification, and range finding SFP reticules are only accurate at one magnification, typically the highest.
Q: What magnification is my mildot reticule accurate at?
A: See the above question, read the manual, and call the company if you're still not sure.
Q: What are M1, M2, and M3 dials?
A: These are designations used by Leupold to signify the value of the elevation adjustments on their Tactical line of scopes. M1 is 1/4 MOA,M2 is 1/2 MOA, and M3 is 1 MOA. M2 and M3 scopes also have a BDC, as explained above.
Q: What difference does tube diameter make? Which is best?
A: Scopes come in several different body tube diameters. The two most common are 1 inch and 30mm. Larger tube diameters allow for more elevation adjustment and generally make for a stronger scope. The downside is the bigger they get, the heavier they are, and the smaller ring selection gets. The most popular tube diameter is 1 inch in the USA.
Q: My local gun shop doesn't have/can't get the scope I want. Help!
A: The Internet is the answer to your prayers. Scopes are available everywhere
Q: OK, I've got my shiny new scope, but those mounts are going to require me to sell a kidney. Are bomb-proof mounts a must?
A: If your rifle is destined for serious use (read: likely to see active duty in a military/police/protection of life setting) then yes.If not, then you can get away with rings and bases that didn't cost as much as your last car payment. Burris XTR rings being a popular example.
Q: What height rings do I need to mount my ________ scope?
A: Read the manual. Consult the manufacturer. Leupold has a chart in their catalog indicating which rings for which scopes on which rifles.If you decide to wing it, just remember: do not allow the objective bell to touch the barrel.
Q: Does my scope have enough adjustment to make it to 1000 yards?
A: This is determined mainly by your scope's total elevation, which should be listed in the manual or on the manufacturer's website. Look at the drop tables for your specific cartridge and figure out how much"up" is required to make it to 1000 yards. If you don't have enough,you may be able to get it with a slanted scope base, such as the 20 MOA bases now popular. To use these, mount the scope, dial 20 MOA down, and then proceed to zero. When you are finished, loosen the screws on the elevation knob cap and position it to read zero. You now have more "up"elevation, and should be able to make it to 1000 with most popular scopes. Consult your scope manufacturer if you're not sure.
Q: Which is better: one piece or two piece bases?
A: This is another matter of personal preference. It makes little real difference. One piece rails will allow for slanted bases and allow you to mount other gadgets like a bubble level, while two piece bases weigh less and allow easier access to the loading port.
Q: OK, I've got it all figured out. I bought the best scope I could find, with a big objective and a slanted base. But now I'm having trouble getting my face on the stock properly.What gives?
A: A good cheek weld (placement of the face on the stock) is important to accurate shooting. The height of the mounted scope combined with the height of the stock's comb determines your cheek weld. Large objective scopes must be mounted high to clear the barrel, and slanted bases raise the ocular lense (the one you look through) even higher. Having a bad or non-existent cheek weld on a precision rifle is a problem. It can be remedied by going with a scope with a smaller objective, on a shorter, non-slanted base. If your scope has 100MOA or more of total elevation adjustment, you should still be fine for 1k. If you must have the slanted base and large objective, get a stock with an adjustable cheek piece.
ALSO, a scope must be mounted far enough back so when you bring the gun to bear the eye relief is the proper distance so you have a full view of the field without having to move your head forward.
If you would like to see anything added to this FAQ, please let me know. If you can't find what you're looking for here, just ask. The friendly members here at the site will be happy to help you.
Stay safe and shoot true.
