Scope sense: What power/range scope do we need?

This is a discussion on Scope sense: What power/range scope do we need? within the General Firearm Discussion forums, part of the Related Topics category; I've bought a few scopes recently and there are many things to consider: cost, weight, size, clarity, a biggy - parallax, brightness, ruggedness, eye relief, ...

Page 1 of 2 12 LastLast
Results 1 to 15 of 16
Like Tree7Likes

Thread: Scope sense: What power/range scope do we need?

  1. #1
    Senior Moderator
    Array Tangle's Avatar
    Join Date
    Dec 2004
    Location
    Chattanooga
    Posts
    9,647

    Scope sense: What power/range scope do we need?

    I've bought a few scopes recently and there are many things to consider: cost, weight, size, clarity, a biggy - parallax, brightness, ruggedness, eye relief, etc. and no less significant magnification.

    Like just about everyone does, I had to give a lot of thought to magnification based on my anticipated applications. There are essentially two categories we can put scope applications in. There are actually more than two, but not including bench rest type shooting, two fills most of our intended uses and they are self-defense and hunting. And certainly there is ample overlap such that one can serve in some capacity in both categories.

    Just about all the characteristics of scopes have been discussed repeatedly somewhere, so I won't get into all that - again. So what I do want to offer is a way to look at scope power exclusively. Of course this assumes the proverbial "...all else being equal..." and we can assume that I think by considering the same manufacturer and model with the only difference being magnification and the attendant weight/length required to accommodate the respective magnification.

    I've read lot's of literature about how to select the best scope/magnification, etc. and they are all for the most part good and informative. However, it is still up to us to sort through everything and plunk down our money. So here's my approach to power/magnification.

    For self-defense, I want a 1x power available. That allows a both eyes open approach and at 1x, most of the scopes I've seen will work well right up to about three feet from the muzzle and even right at the muzzle, they'll work - they may not be in perfect focus, but very useable. Further for SD, I like a 4-5x option for longer shots. I like a tactical reticle in SD scopes, for fast target acquisition, but that's a different subject. For hunting, a SD scope can work well but there may be better choices for the longer ranges one might encounter in a hunting situation. If you are in an area where 100 yards shots are about the max, a 1-4x SD scope should be great.

    So I shot, and shot, and shot, and shot various rifles, e.g. Mossberg MVP 5.56, Remington 700 SPS Tactical .306, Armalite AR-10, two Diamondback AR-15s (1:9 twist), and a Troy Defense 5.56 with a 1:7 twist. I shot with various scopes brands, powers, and reticles. No surprise to me, I discovered some things. One, and probably no surprise to anyone, more power simply gives you a better picture of the target/reticle relationship. That doesn't necessarily mean more accuracy, but it can mean that, and gives the potential to shoot more accurately.

    Still, I was searching for some rule of thumb to apply to selecting the power of a scope - and this is it. It's certainly not in concrete, but it is logical and a helpful concept. I began to think about why I need power in a scope. It's to see the target bigger, but also to see details of the target better. Also to see how closely you are holding the reticle to the intended POI (point of impact). Well, that doesn't help a lot, we all already knew that, so I went with this. How accurately would I want to be able to shoot at a given range? Let's take 50 yards as an example. I've fired easily 500 rounds at 50 yards over time with the various combos of scopes and rifles to measure precision. I chose precision here rather than accuracy, because precision is what I wanted to measure.

    I decided my base line would be to establish a group size at 50 yards and translate that via scope requirements out to 100, 200, 300, and even further. So for me, not you, for me, with my eyes, I can shoot 0.48 MOA groups at 50 yards, but everything has to be right - wind, sun, shade, me, etc. So I decided 1 MOA at 50 yards was a more reasonable goal with various conditions. So I looked at the power of a scope I needed with my eyes to consistently shoot 1 MOA groups at 50 yards. I found that a 3x scope was about right for me. Of course other things come into play here, the type of reticle especially, but again, that's a different subject.

    With a baseline of 3x at 50 yards I thought, what power would I need to see the same target picture at 100 yards? Well, I'd need twice as much magnification or 6x. At 200 yards I'd need 4 times as much magnification or 12x.

    So my rule of thumb for scope power estimation is to determine what group size you can live with at a given range and determine what magnification you need to achieve that group size consistently. It's real easy to see those good days and expect to shoot that every time - you won't and can't - at least I can't and I doubt I'm unique about that. Once you establish the group size at a range, pick a scope that will give you the same picture at longer ranges. Don't choose more power than you need. Likely, you'll be better off with a little less power than a little more power.

    And there is a caveat to this rule of thumb, it can estimate scope ranges that are not available, but that just means you'll have to decide if you want to go with the longer range power estimate and take what you can get for the shorter ranges, or vice versa, go with the shorter range power and take what the scope range will give you at the longer range.

    Most scope power ranges are 3:1 and 4:1. There are some with 5:1 ranges and even a few with 6:1 ranges. Common ranges are 2-7x, 3-9x probably the most popular, 4-12x, and 4-16x. It's a bit off topic, but higher powers have issues that lower power scopes don't. Don't 'over-power' yourself.

    Here's another way to think about this: if you're shooting at 100 yards, a 2x scope will be somewhat like shooting at 50 yards target-wise. A 3x scope would be like shooting at 33 yards. A 4x scope would be like shooting at 25 yards.

    Let's say you anticipate shooting from 50 to 200 yards. What would be a good power range for your scope? Well determine what power it takes to shoot a consistent group size at 50 yards and that power is your baseline. Let's say it's 3x at 50 yards. Then since 200 is 4 times further than 50 the maximum power should be about 4 x 3 = 12x. So you would need a 3-12x scope. Unfortunately 3-12 power scopes are hard to come by, so now what? I'd say go to a 3-9x which is readily available. Or, you could go with a 4-12x which would give you the long range power and a bit more power than 3 at the shorter range.

    The scope power rule of thumb is simply a guideline. Other factors often have to be considered. E.g. power selection may need to be modified to take into account sighting on a moving target where field of view might be significant. FOV and power are inversely proportional - at a given range, more of one means less of the other.
    I'm too young to be this old!
    Getting old isn't good for you!

  2. Remove Ads

  3. #2
    VIP Member Array StormRhydr's Avatar
    Join Date
    Jun 2013
    Location
    Music City, USA
    Posts
    2,541
    Nice write up. Thanks for sharing:)

  4. #3
    VIP Member Array Rollo's Avatar
    Join Date
    Sep 2009
    Location
    Indiana
    Posts
    3,003
    Good info Tangle! I have been struggling with this subject myself quite a bit. Previously I had a red dot on my defensive/shtf AR and I really liked it. I could shoot acceptable groups at 50-100 yards. Anything past that I could put accurate fire on a man size silhouette but I would exactly call them groups. I picked up a new Primary Arms 1x6 scope because I wanted to be able to extend range and be able to possibly identify targets at greater ranges. I don't ever see myself needed to have even use AR for a defensive/shtf situation but I liked the idea of being able to engage targets at a pretty wide range of distances. I REALLY like the scope. It's got great eye relief and the 1x with their ACS reticule is great as it's pretty much like a red dot. The problem is the weight. The scope plus mount adds about 1.5 pounds to the rifle. That doesn't sound like much on paper but I REALLY noticed the difference when I was running drills. Fatigue started to set in a LOT faster when I was shooting unsupported. When I built this AR my aim was to keep the weight as low as possible. The only thing I have mounted on it other than a optic is a light weight flashlight. Now I am torn. I love the capability of the 1x6 but the weight has me thinking I might switch back to my dot.
    -It is a seriously scary thought that there are subsets of American society that think being intellectual is a BAD thing...

  5. #4
    VIP Member
    Array Mike1956's Avatar
    Join Date
    Sep 2011
    Location
    Marion County, Ohio
    Posts
    9,130
    Good post, Tangle. I run a 6x18 Leupold on my Remmy, which allows me to see a two-inch orange target at 1000 yards.
    "Who are the ones that we kept in charge? Killers, thieves, and lawyers"

    Tom Waits, God's Away on Business

  6. #5
    Senior Moderator
    Array Tangle's Avatar
    Join Date
    Dec 2004
    Location
    Chattanooga
    Posts
    9,647
    Quote Originally Posted by Rollo View Post
    Good info Tangle!
    Many thanks Rollo!
    Quote Originally Posted by Rollo View Post
    ...Previously I had a red dot on my defensive/shtf AR and I really liked it. I could shoot acceptable groups at 50-100 yards. Anything past that I could put accurate fire on a man size silhouette but I would exactly call them groups.
    I know what you mean. Due to RK surgery I had many years ago (20 or so) I have problems with red dot sights. If I didn't, Aimpoints would be about all I'd use. It's funny, scopes, even with dots at the cross hair intersection doesn't give me a problem, nor does the cross hairs or any other kind of true scope reticle. I'm pretty sure the difference is that scopes have exit pupil sizes that eliminate the multiple dots I see because the entire picture is going through the center of my eye and the RK slits aren't there. The red dots are simply like looking at a dot, i.e. no exit pupil.

    Quote Originally Posted by Rollo View Post
    ...I picked up a new Primary Arms 1x6 scope because I wanted to be able to extend range and be able to possibly identify targets at greater ranges...The problem is the weight. The scope plus mount adds about 1.5 pounds to the rifle. That doesn't sound like much on paper but I REALLY noticed the difference when I was running drills. Fatigue started to set in a LOT faster when I was shooting unsupported. When I built this AR my aim was to keep the weight as low as possible. The only thing I have mounted on it other than a optic is a light weight flashlight. Now I am torn. I love the capability of the 1x6 but the weight has me thinking I might switch back to my dot.
    I was surprised at how much scopes weigh when I started doing research on them. And, as you say, weight does add up with time.

    I recently bought a Vortex Viper PST 1-4x and it's a great scope. I bought it because it only weighs 16 oz. That's 50%, or a full half pound lighter than the PA scope. But, it only goes from 1x to 4x. So if you could live with the cost and 4x max, you could shed a half a pound from your rifle.

    This scope is rugged enough, but has a bit thinner tube wall than some other scopes, so if you do get one, don't torque the rings down more than 15 inch-pounds. And I strongly recommend the Vortex base for this scope. The Burris PEPR didn't work so well with it.
    I'm too young to be this old!
    Getting old isn't good for you!

  7. #6
    Senior Moderator
    Array Tangle's Avatar
    Join Date
    Dec 2004
    Location
    Chattanooga
    Posts
    9,647
    Quote Originally Posted by Mike1956 View Post
    Good post, Tangle. I run a 6x18 Leupold on my Remmy, which allows me to see a two-inch orange target at 1000 yards.
    Thanks Mike. I hear about mirages with high power scopes. Do you know what that's about and have you noticed it at 18x? Thanks!
    I'm too young to be this old!
    Getting old isn't good for you!

  8. #7
    VIP Member
    Array Mike1956's Avatar
    Join Date
    Sep 2011
    Location
    Marion County, Ohio
    Posts
    9,130
    Quote Originally Posted by Tangle View Post
    Thanks Mike. I hear about mirages with high power scopes. Do you know what that's about and have you noticed it at 18x? Thanks!
    No, I have never experienced any mirages through it. About the only time I crank it up that high for shots is beyond seven hundred yards. I also bird and game-watch with it. At five hundred yards, I could see the spotted eagle on the ground eyeballing me. If there is a downside to that kind of magnification power at range, I have yet to discover it.
    "Who are the ones that we kept in charge? Killers, thieves, and lawyers"

    Tom Waits, God's Away on Business

  9. #8
    Moderator
    Array bmcgilvray's Avatar
    Join Date
    May 2007
    Location
    Texas
    Posts
    9,415
    Whew! I'm out of date. Other than a 6X18 Burris target scope on a .220 Swift, my center fire hunting rifles all wear 4X or 6X scopes by choice.

    Very good, thoughtful narrative you produced, Tangle. Just the kind of though-provoking information the Forum needs.
    “No possible rapidity of fire can atone for habitual carelessness of aim with the first shot.”

    Theodore Roosevelt, The Wilderness Hunter, 1893

  10. #9
    Member Array Bassindude's Avatar
    Join Date
    Jun 2013
    Location
    Avon, Indiana
    Posts
    96
    Great info, thanks for sharing. Jim
    1911 responds much quicker than 911

  11. #10
    Senior Moderator
    Array Tangle's Avatar
    Join Date
    Dec 2004
    Location
    Chattanooga
    Posts
    9,647
    Quote Originally Posted by Mike1956 View Post
    No, I have never experienced any mirages through it. About the only time I crank it up that high for shots is beyond seven hundred yards. I also bird and game-watch with it. At five hundred yards, I could see the spotted eagle on the ground eyeballing me. If there is a downside to that kind of magnification power at range, I have yet to discover it.
    I got to shoot with a 40x scope on a 22 pound bench rest rifle at 100 yards - it was just like being there!!! Like you, I didn't see any issues either. But the guys that shoot high power scopes talk about hmmm...stuff.

    That sounds like quiet a scope you have!
    I'm too young to be this old!
    Getting old isn't good for you!

  12. #11
    VIP Member
    Array Mike1956's Avatar
    Join Date
    Sep 2011
    Location
    Marion County, Ohio
    Posts
    9,130
    Quote Originally Posted by Tangle View Post
    I got to shoot with a 40x scope on a 22 pound bench rest rifle at 100 yards - it was just like being there!!! Like you, I didn't see any issues either. But the guys that shoot high power scopes talk about hmmm...stuff.

    That sounds like quiet a scope you have!
    I have been extremely satisfied with its performance and reliability. At about half the price of a comparable Nightforce, it is all I need for what it's for.
    "Who are the ones that we kept in charge? Killers, thieves, and lawyers"

    Tom Waits, God's Away on Business

  13. #12
    VIP Member
    Array OldVet's Avatar
    Join Date
    Nov 2009
    Location
    S. Florida, north of the Miami mess, south of the Mouse trap
    Posts
    14,598
    I have a 3x9 on both my .223 and .30-06. The 3x9 is great on the .223 when looking for that rockchuck head poking out of a cliff at 300 yards, but in all reality I wish I had a 2x7 for the -06. The primary use of my rifles is (was) hunting, not knocking brass buttons off zombies at 1000 yards.
    Tangle likes this.
    Retired USAF E-8. Avatar is OldVet from days long gone. Oh, to be young again.
    Paranoia strikes deep, into your heart it will creep. It starts when you're always afraid... "For What It's Worth" Buffalo Springfield

  14. #13
    Senior Moderator
    Array Tangle's Avatar
    Join Date
    Dec 2004
    Location
    Chattanooga
    Posts
    9,647
    Quote Originally Posted by Mike1956 View Post
    I have been extremely satisfied with its performance and reliability. At about half the price of a comparable Nightforce, it is all I need for what it's for.
    That touches on another point about scopes. It's easy to get the impression if one doesn't have a $1500 NF, etc., he won't be able to shoot well. That's simply not true. Most of us will never be in a situation so sensitive that the utmost clarity and brightness makes or breaks the shot or that it will make any difference at all.
    OldVet likes this.
    I'm too young to be this old!
    Getting old isn't good for you!

  15. #14
    VIP Member
    Array OldVet's Avatar
    Join Date
    Nov 2009
    Location
    S. Florida, north of the Miami mess, south of the Mouse trap
    Posts
    14,598
    I look at buying a top-of-the-line, super-power, all-bells-and-gizmos, super-duper-can't miss scope the same way I do as the latest and greatest smartphone--all I do is call someone. My Bushnells have done everything I've required of them. But that just me, some can't breath air unless they have the very best, even when it exceeds their capabilities.
    Tangle likes this.
    Retired USAF E-8. Avatar is OldVet from days long gone. Oh, to be young again.
    Paranoia strikes deep, into your heart it will creep. It starts when you're always afraid... "For What It's Worth" Buffalo Springfield

  16. #15
    Senior Moderator
    Array Tangle's Avatar
    Join Date
    Dec 2004
    Location
    Chattanooga
    Posts
    9,647
    Quote Originally Posted by OldVet View Post
    I look at buying a top-of-the-line, super-power, all-bells-and-gizmos, super-duper-can't miss scope the same way I do as the latest and greatest smartphone--all I do is call someone. My Bushnells have done everything I've required of them. But that just me, some can't breath air unless they have the very best, even when it exceeds their capabilities.
    Absolutely! I feel the same way. I do have a couple of mid-range price scopes, but I see little if any advantage in them. One exception is my Viper PST, it's advantage to me is smaller size and lighter weight.

    Actually I feel the same about ARs. I realize there are "premium" ARs out there. If I was going to combat and be dragging the gun through mud, blood, sand, etc. and shoot tens of thousands of rounds then maybe, maybe a top priced AR would offer some benefits. I make it a personal rule to buy the mainstream manufacturers ARs - haven't been disappointed yet.
    I'm too young to be this old!
    Getting old isn't good for you!

Page 1 of 2 12 LastLast

Links

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

Search tags for this page

diamond back ar rifles

,

does a high power scope more accurate

,

group size with 3 12 power scope

,

m14 1x6 scope

,

scope ranges powers

Click on a term to search for related topics.