In the past, general purpose rifle was a hunting style bolt action rifle chambered for 30-06 or something along those lines. Well, the times have changed and more and more of the gun enthusiasts and hunters in this country are virtually brought up on ARs. I suppose that being America’s primary battle rifle for a few decades helps propagate the design a bit.
To me, a general purpose rifle is a jack of all trades and a master of none. I own one rifle that is kind of like that, although when I was putting it together, general purpose anything was the last thing on my mind. I was trying to build the best compact long range gun I could on an AR-15 action. I ended up with a rifle that sports an 18” barrel with a 264LBC chamber (a version of 6.5 Grendel). With the right bullet, this cartridge is supersonic to 1000 yards (900 yards at sea level) and can work for anything from home protection, to hunting, to target shooting, to plinking in a pinch. It has very light recoil and is quite accurate, so I ended up using it for scope testing quite a bit. By now, I have had every scope type known to man mounted on that rifle, so I have developed a pretty clear idea of what works well on it.
Before I get any further with this, I want to elaborate a little more on rifle choice. If you are looking for a general purpose rifle and want it to be built on an AR platform, sit down and put together a list of what you will use it for. If the list is dominated by tasks like plinking and home defense with occasional varminting thrown in, you should be looking at an AR-15 variant chambered for 223Rem/5.56x45. Yes, I know that the military found this cartridge less than optimal for taking people down, but keep in mind that the military is prohibited from using well-constructed bullets. We can use any bullets we want and loads that utilize bullets like Nosler Partition and Barnes TSX make the little cartridge effective enough, while still giving you access to a variety of plinking ammo.
If your list leans a bit more heavily toward stopping power and you do not mind reloading, take a close look at the various cartridges that fit into AR-15 action, but deliver a heavier bullet. The three most common ones are 300AAC Blackout, 6.5Grendel/264LBC and 6.8SPC. I own rifles chambered for both the Blackout and the Grendel, and I have a bit of experience with 6.8SPC as well. If you plan to get a suppressor, get the Blackout. Your effective range is closer than with the Grendel, but you can have both supersonic and subsonic loads that shoot a much bigger bullet than 5.56x45 does. If you are not planning to get a suppressor, this comes down to 6.5Grendel and 6.8SPC. To be perfectly blunt, I think the Grendel is a better cartridge than the 6.8SPC overall, but its biggest advantage is long range. If you want your general purpose AR to reach waaay out there, get the Grendel. For applications within 400 yards, there is little to differentiate the two.
Lastly, if your idea of a general purpose cartridge means hunting first and foremost, do yourself a favor and step up to the larger AR-10 platform. If you still want to plink with it, stick with 308Win/7.62x51 chambering. If you reload, any round based on the 308 case will do the trick: 260Rem, 7mm08, etc.
Now, let’s look at the requirements for scopes to mount on one of these rifles:
- Variable magnification with low end no higher than 3x (or a fixed 4x or 6x power scope if you are old fashioned)
- Top end magnification in the 9x to 18x range.
- Objective lens in the 32mm to 44mm diameter. Larger diameter objectives work well on ARs, but it is too easy to end with a scope that really upsets the balance of the gun, so I suggest staying in the ballpark of 40mm.
- The reticle has to work well in low light either through line thickness of illumination.
- Both FFP and SFP reticle work fine and the choice between the two is personal.
If you look at this list carefully, you’ll realize that every scope I recommended for SPR applications will work well here. However, we can expand it by a fair bit. For example, a lot of hunters prefer the sight picture provided by the SFP reticles (reticles that do not change apparent size as you change magnification) and if you do not use the reticle for holdover or range estimation, SFP reticle is a very good way to go.
Since my requirements here open the door to a lot of hunting scopes, there are several very serviceable inexpensive options:
- $200 and under: Both Vortex Diamondback and Burris Fullfield make very nicely sorted out 2-7x35 and 3-9x40 scopes. They are very sturdy and have decent reticle. If you are on a budget, these should be at the top of your list. If you want something with cartridge specific turrets and reticles, Nikon’s P-223 (for 223Rem rifles) and P-300 (for 300 Blackout rifles) are good options.
- $400 and under: while it looks like a serious jump up in cost compared to the price range above, it does not get you all that much more. However, your options do open up some. Meopta Meopro 3-9x42 is a solid step up in optical quality, for example. Also, Nikon M-223 scopes (with 2-8x32 being my favourite) offer good optics with cartridge specific BDC turrets. Lastly, if your idea of a general purpose AR includes varminting or other pursuits requiring high magnification, Sightron SII 4-6x42 is worth a look.
- above $600: frankly, most general purpose ARs have scopes that are a little cheaper than this and most of what I would recommend here, I already mentioned in the article on scopes for SPR rifles.
There are of course other options and the variety available out there is staggering. ARs are very versatile rifles, so they can comfortably support almost any scope unless it is so large it outweighs the rifle itself. Hence, before I wrap up, I will touch on three different configurations that I have played with.
Configuration 1: you’ll do everything with this rifle, but your overall emphasis is on quick plinking and self-defense. You are not looking for extreme precision and you are not happy with iron sights alone. Perhaps, you will be happy with a decent red dot sight. There are many to choose from, some of which I have mentioned in previous articles, like Aimpoints and Trijicon SRS. However, those are expensive. In lower price ranges, Lucid sights are worth a look and they are an easy fit for ARs.
Configuration 2: you want some magnification, but you also want the simplest possible manual of arms, i.e. nothing to adjust. You want to shoulder a rifle and have the image right in front of you with some magnification. You want it there regardless of lighting conditions and you want it simple to use. Prepare to spend a little money, then. You should be looking at a few offerings that cost right around $1000: Trijicon Acog, Leupold HAMR, Elcan, etc. Here is what a 4x32 Acog looks like on an AR-15:
Configuration 3: Your general purpose AR is also you general purpose rifle. You want to use this thing for, literally, everything from plinking to big game hunting to shooting coyotes to just about anything. There is a good chance your AR is chambered for something beefier than the 223, which makes it a legitimate big game hunting rifle among other things. You are willing to put in some serious money into a sight that would do almost everything well. If this sounds familiar, consider something like this:
This is a 3.5-14x42 Leica ER scope. It is not cheap, but it is absolutely superb. There are competing design that are just as good from Swarovski, Zeiss and others, but the Leica is a bit more affordable than those and easily as good overall and better in some ways.