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Low Power Variable Optic Vs. Prism Scope for your Budget AR-15 [Complete 2019 Guide]

Primary Arms Staff

12/3/2018 10:08 amwww.primaryarms.com

Prism Scopes or Low Powered Variable Zoom for Your Budget Rifle

The AR 15 is America's rifle. If you're reading this, you've probably got one of these freedom machines. Maybe even more than one. But if you're like me, and you live on a budget that unfortunately requires you to spend a lot of too much of your hard-earned paycheck on things that aren't guns, maybe you've got to be a little more creative with your gear load-out. Getting the most out of my one-and-only rifle means I need to know how to build the best all-around AR 15 on a budget, so that's what I set out to do. After making the necessary upgrades in parts and hardware, I landed at a fork in the road… What to put up on top.

Equipping yourself with a single "do-it-all" rifle that maximizes the potential of the AR 15 platform across many common applications is definitely an achievable endeavor. So, for someone on a budget like me – and maybe you – that one AR that we own needs to be purpose-built to maximize utility. There's a few elements to consider when building or buying a rifle that will go a long way towards achieving that "one rifle for everything" performance. Things like a free-float handguard that allows your barrel harmonics to be free of contact points and make you more accurate. Or an upgraded trigger to get you above MILSPEC performance. But assuming you have made some of those upgrade to your rifle already, let's talk about optics.

I want to get the most out of what I have without breaking the bank, and I think that's a worthy endeavor for anyone -- regardless of how many rifles you've got in the safe. For your "SHTF" rifle, or "workhorse", or "RECCE" – whatever you want to call it – the one rifle that will handle everything from zero to 600 yards… what's the best optic to employ on that rifle to make the most of its abilities in the widest set of circumstances? That's the question I had to ask myself when I arrived at my impasse on the road to single-rifle-domination. If you're wondering what to put on top of your do-it-all rifle, lets figure it out together.

The Contenders:

Prism scopes and low-power variable optics are by no means your only choices for a versatile optic solution on your rifle. Here at Primary Arms, we built our reputation on the red dot sight, and many people use red dots to get versatile close quarters and short-range performance out of their rifle with the added option of reaching out to slightly further distances using a red dot magnifier. This is a good solution, and usually a relatively affordable one. However, what we are after here is an optics solution that is going to give us accurate, magnified performance with advanced reticle features like bullet drop compensation and wind holds so we can be as equipped as possible in the widest number of circumstances with the fewest number of compromises. All without busting the budget. That's a tall order. But it can be done! With this in mind, thought, for our purposes, we're going to limit our discussion to low power variable optics and prism scopes.

Variable power magnified rifle optics aren't new, but they have gotten a lot more advanced over the last few decades, both in their capabilities and their construction. These days, we are able to affordably enjoy incredible feats of engineering sitting atop our rifles that allow us to hit targets, harvest game, or identify threats from many hundreds of yards away without sacrificing performance up close. Having the ability to select a magnification range from 1X to 6X or even 8X in one optic unit is pretty amazing in terms of utility. That's a large part of why low power variable optics were popular with the military long before they found their more recent popularity in the civilian market. At 1X power with a well-designed reticle, a low power optic can be incredibly fast to get on-target, and with proper training they can be absolutely as effective as a red dot for CQB applications. Many of these types of scopes are now offering first focal plane iterations of the optic, which means that the reticle appears to grow and shrink as you raise and lower the magnification setting. For our purposes, this is an immensely useful feature as our scope will provide an unobstructed field of view at the lower powers while still giving us full utilization of the reticle's features -- like bullet drop compensation and wind holds -- as we move up in magnification to the high powers. For a first focal plane scope especially, the key to getting the most out of an optic is really the reticle. So many companies are putting out great products that are built tough using quality materials and have incredibly clear glass. So it takes a little more utility built in to the product to really set an optic apart from the competition. When you're putting together a do-it-all rifle, those extra features are awesome to have.

Okay, so what are the downsides? For one, variable magnification optics are large. They take up a lot of real estate on top of a rifle and add a pound or two to its weight. If one of the things you're looking to do with this do-it-all budget rifle is stalk game across large areas of land, saving weight where you can is important. Important enough to steer you away from this option? You'll have to make that call for yourself.

Another drawback to note comes when variable magnification scopes are made in a second focal plane configuration. Second focal plane scopes are generally more common and more widely available than first focal plane configurations because they're a little easier to manufacture and a little cheaper to buy. There's nothing wrong with a second focal plane scope, but because the reticle won't change size as we scale through magnification, we'll have to get picky with the reticle. For a rifle like the one we are after, usefulness at close quarters is every bit as important as accuracy at distance. With that in mind, a simpler reticle with an unobstructed field of view is essential when we can't simply shrink the reticle out of the way. This may result in a lack of features like bullet drop compensation, ranging, or wind holds. Just some things to be mindful of.

As you may be thinking, especially if you're in this budgeting boat along with me, we want to be able to build a do-it-all rifle and maximize our utility without having to take out a second mortgage. So what are the affordable options for a high-quality low power variable optic? Here's what I would consider to be three top-quality choices for a low power variable optic. Two that won't bust the budget, and one for some serious performance:




Some say prism scopes are the ideal optic solution for the AR 15 platform. They have become very popular -- and much more affordable -- over the last decade or so. But are they the right solution for people like us? People who are trying to do it all with just one rifle and also not contribute to the National debt? Let's break it down.

How does a prism scope work? Just like your binoculars.

Instead of using two lenses at each end of a tube that refract light, magnify an image, and then flip it back right-side-up for your eye, a prism scope uses two opposing prisms that reflect the image through their multiple faces to magnify and orient the image, passing the light through an etched reticle as it goes. So, when the image gets to your eye, you see a fixed-power magnified image, oriented properly, with an etched reticle in place over it.

What makes the prism scope the best scope for the AR-15 in some people's minds? There are a few factors to consider. One of the easiest to identify is their compact, rugged design. Compared to standard telescopic and variable zoom rifle scopes, a prism scope can take up about half the amount of space on your rifle, if not less. Variations in the sizes of prism scopes do exist, and they depend on the fixed magnification power of the sight, but generally speaking one could mount a prism scope in a comfortable position and still have plenty of room for back up iron sights if the optic were to completely and catastrophically fail. A benefit of prism scopes with an etched reticle, however, is that even with no power -- a dead or faulty battery, for instance -- the reticle is still there, just not illuminated. It should be noted, also, co-witnessing through a prism sight is not possible. In a worst-case scenario, we would need to physically remove the prism scope to make use of the iron sights on our rifle.

Aside from the smaller footprint, prisms are durable and ruggedly constructed. The most iconic prism scope, the Trijicon ACOG, is known for it's combat effectiveness and ability to stand up to serious abuse in military applications. While many variable power optics are very sturdy and will stand up to abuse, a prism scope will almost always be able to withstand more. Prisms take up less room internally to achieve a magnified sight picture, allowing for a more compact design. Manufactures utilize the smaller design to add more robust housings to prism scopes when compared to larger telescopic scopes, all without adding too much bulk or weight.

Alright, let's talk downsides. The most obvious drawback with a prism scope is the loss of variable magnification. However, some argue that the fixed power means more simple and intuitive operation. Verses a low-power variable optic in a second focal plane configuration, a prism scope takes all the concern out of wondering if your BDC or wind holds will be true. It never changes in size, and therefore will always be accurately calibrated. With advanced features built into the reticle of a prism scope, it's possible to be lethally accurate out to our desired distance of 600 yards. So what about CQB? Some say that shooting a prism scope with both eyes open is just as easy and effective as doing so with a red dot sight, and with enough training, that might be the case. But if you go towards the high end in magnification for a prism scope -- which seems like the intelligent thing to do if we are looking to be effective out to 600 yards -- binocular shooting will get more difficult and less intuitive. Even with all that being considered, the utility and toughness of a prism scope can't be ignored. Prism scopes are known for having forgiving eye boxes, good eye relief, and wide field of view. Not to mention, their size and weight simply can't be matched by a variable optic.

When it comes to cost, it depends on what you buy, of course, and where you buy from. But there's a lot of prism scope options out there at prices comparable to just about any low power variable optic. And you won't have to sacrifice quality, either, as long as you buy smart. So here are 3 prism scopes for a do-it-all rifle, two that wont bust the budget and one for those of you who want to spend a little more cash:




Okay folks, it's decision time. When the rubber meets the road, which are you going to go with? The best thing I can tell you is go get behind one of each of these scope options at your local gun store or find a friend who owns one. Or, read up on what people have to say about each product. Narrow the discussion down to the few applications you're most concerned with in your do-it-all set up. Only you are going to be able to make the decision. My opinion can't make your decision for you because I'm not you. What I say isn't the gospel. But I hope that coming along with me in my journey to decide which is going on top of my rifle has given you the chance to weigh the pros and cons of each optics solution.

If you really want to know which optic I decided to put on my do-it-all budget AR 15, you're gonna have to come find me. I'll be at the range. See ya out there.