We recentrly reviewed a Vortex Viper 3.5-10x50mm scope as a basic scope review and indicated then that we would be bringing in one of their more tactical focused scopes for review. Well, this is part two in the series of Vortex scope reviews we will be doing. This time around we did want to review one of their tactical scopes and the Viper PST (Precision Shooting Tactical) is their mid range tactical series of scopes that sits below the high end Razor tactical scopes. We had one of our readers volunteer to allow his 4-16x50mm scope to go through our testing and like usual we appreciate our readers’ willingness to help out.


If you have not read our review of the Vortex Viper 3.5-10x50mm you can do that to get a bit more information about the base Vortex Viper line of scopes. For the PST the intent was to take that base scope and add some target/tactical features to them to tailor the scopes for the sniping or target shooting community and yet keep the price under $1000. Some of these features include large exposed target knobs, zerostop, illuminated First Focal Plane (FFP) reticle, and 30mm tube. The price does bump up a decent amount so it becomes the classic debate of compromise in price or features. The scope is marked “Made in the Philippines”, where some other decent quality scopes are being made by and for other manufacturers. The scope comes packaged well in a nice box with some decent instructions, bikini style lens caps, fine lint-less cloth, shims for the zerostop, battery and a sunshade. This pretty much covers all of the basics that one would need with the scope.


One of the features with the PST version of the Viper line of scopes is that they all have a one piece 30mm tube that is machined from a single block of aircraft grade 6061-T6 aluminum. All of the angles have a crisp machined look to them and the tube construction looks nice. The finish on the scope tube is a hard anodized finish in a nice matte black to minimize any reflections. There is a generous amount of area on the rear portion of the scope for the scope mounting rings, but the space in front of the turrets is more limited, though still enough to handle most scope mounting scenarios. The markings on the scope are an off-white color, which may actually be exposed etched aluminum with a clear matte finish applied, it is hard to tell. The overall size of the scope is about the size of a large hunting scope and not too large such as Vortex’s own Razor series. The proportions are nice and the scope tube has a good functional look to it.


The eyepiece of the scope is a fast focus eye piece that covers the entire adjustment range in about 1.3 rotations. It rotates smoothly with minimal force and operates and focuses the reticle as needed. There is no lock on the eye piece as well as no indicator mark to indicate where eyepiece is set, so there is some chance that it could rotate unbeknownst to the operator, though if flip-up scope caps are used it would offer an indication it has moved and by how much. The eyepiece does have a large rubber protective ring on the end about half an inch deep, providing protection for the shooter from a “scope kiss” but it also puts the scope about a half inch closer to the shooters eye because it is so deep..

Just in front of the adjustable eye piece is the illumination controls for the illuminated reticle. The control knob is set at a 45 degree angle to avoid completely blocking the elevation or side focus knobs from view when behind the scope. The illumination control goes from 1 through 10 with an off position between each number. There are distinct clicks for each setting and for each off position to positively identify which setting you are on. There is also a tick mark for identifying where the knob is positioned. Only the inside, thinner portion of the reticle is illuminated and there are no signs of leaking light or over illumination in the scope tube.


In front of the eyepiece is the magnification adjustment ring which has some fairly aggressive serrations on it to help with providing grip in all weather conditions. One thing we liked on the standard Vortex Viper scopes was the elevated tabs with the magnification labels on them so you can tell what power the scope is set at without raising your eye away from the scope. They were a bit large on the standard Viper we tested, but on this PST they are smaller and not so prominent. They are still clearly labeled and easy to see from behind the scope making this implementation of the idea even better by not being as large but being just as functional. One thing that may seem odd is that there is a marking at 5.3x instead of 6x, the reason is because when set at 5.3x, it makes the space between each dot exact 3 mils instead of one. The index mark is a high visibility red colored fiber optic style indicator that shows up well. It is similar to some of the high visibility open sights that are available on some pistols as well as rifles. It does provide a good and easily visible indicator mark for the power ring. The power ring rotates through the magnification range smoothly with just about the right amount of resistance. There is a bit of “sloppiness” or “take-up” in the power select ring when changing direction, such as when you crank it up to 16x and then switch to go down in power. We would like to see that tightened up without the slop.


The elevation, windage and side focus knobs sit up on an elevated shoulder that is rounded and smooth. The elevation and windage knobs are a larger style exposed turret with aggressive serrations on top for grip. The knob sits down inside a turret housing that is fairly unique in that there is a vertical slot in the housing with the rotation markings on the outside of the housing. The rotation markings are used for measuring how many times the knobs has been rotated completely. The vertical slot in the housing makes it so that the bottom of the turret is clearly visible which helps make it easier to determine just which rotational line the knob is at. This is opposite of what most scopes do by having the rotational marks marked on the post over which the turret rests. There are also vertical lines for each click on the knob which shows up clearly in the vertical slot and by following that vertical line up it indicates which mark on the knob is selected. This works well, but that function of seeing the vertical white indicator mark probably has no real advantage over a traditional target style knob. There is also a red high vis mark on top of the knob at the zero mark as well, similar to the power ring indicator mark, and while it is highly visible, we are not sure of the need for a red mark above the zero, as the actual “0” is a pretty good indicator that you are at zero on the knob. There are three different up direction indicators marked around the knob to provide reminders of which way is up and one of those three is pretty much visible at just about any setting on the knob.

Vortex indicates that this Viper PST scope has a total of 21 MIL of vertical adjustment with 5 MIL of adjustment per revolution. This particular sample that we tested had a total of 23.5 MIL of adjustment, providing ample adjustment range when combined with a canted base for most practical shooting ranges for this scope.


Both the elevation and windage knobs have three set screws around the top of the knob which can be loosened with the provided Allen wrench and the knobs “slipped” to zero. This system provides infinite adjustment range and allows the knobs to be lined up perfectly on zero. The elevation knob on the PST scopes also are setup with Vortex’s own zerostop setup that uses a series of shims that you place under the elevation knob once you have the rifle and scope zeroed. You fit as many of the shims under the knob as will fit which then prevents the knob from going any further down. It is a simplistic approach and it works. The one draw back to this simple approach is that it does not provided a hard stop right at zero, instead it gets close but will usually go below zero a few clicks before hitting the stop, though at that point it is clear that you have bottomed it out and the operator just brings the knob back up a few clicks until at zero. For those of you just getting into this and may not know the purpose of a zero stop, it is simply just a quick and easy way to bring your rifle right back down to your “zero” settings on the scope. This is handy when you may have dialed in a lot of vertical adjustments and have gone all the way around the knob more than once. Just spin the knob back down until it stops and you are back to the original zero.

The windage knob is the same size and shape as the elevation knob and it has the same vertical (though horizontal in this case) slot in the turret housing as on the elevation turret and it provides the same functionality as on the elevation knob. The markings on the windage knob count up in both directions and with 5 MIL of adjustment per revolution that means the overlap happens at 2.5 MILS. This provides enough adjustment in a 10 MPH crosswind to take a 175gr 308 Win out to about 900 yards before overlapping. The knob again provides clear direction markings on the knob in 3 locations spaced around the knob. Interestingly, the windage knob does not have the same red high vis indicator on top of the knob at the zero mark like the elevation knob.

The side focus knob is on the left side of the scope and is a bit larger diameter than the elevation and windage knobs and it does not sit down in a housing like the other knobs. The top of the knob has the same serrations on it for providing grip and the knob itself is marked from 50 up to 500 and then infinity yards. Interestingly the knob rotates a decent amount past the 50 on the low end and past the infinity mark on the high end. The knob is easy to grip with the serrations and it rotates smooth and evenly through the entire range requiring just about the right amount of force to insure it does not move inadvertently. The focus of the scope worked below 50 yards out to as far as the eye could see without issue.


The reticle on this Viper PST is what Vortex refers to as the EBR-1 MRAD. The MRAD portion of the name refers to the reticle being calibrated in milliradians. This is a hash mark style reticle with large hashes at each full MIL and small hashes at the half MIL marks. The ERB-1 MRAD reticle does have some of its own unique qualities that are worth pointing out. First, there are a full 10 MILs in each direction from the center crosshairs which is a good amount and when combined with each direction, you have a full 20 MIL to be able to measure targets with. On the up, right, and left stadia, MILS 5 through 8 have small hashes at each .2 MIL which is done in an effort to help the operator be even more accurate with their measuring of the target. One last thing, though we are not so fond of it, are the individual number labels on each even MIL mark (2,4,6, etc). With a reticle that already has a lot going on, the numbers provide additional clutter that can cover details on the target or draw the eye away from the target area. We understand why they do it, in an effort to help speedily determine the number of MILs being measured, but the hashes are clear enough and it is fairly quick and natural for the operator to count the hashes in their head.

viperpst2 viperpst1

The scope is a First Focal Plane (FFP) scope so the reticle does shrink and grow with changes in the magnification setting so that it is always accurate no matter what power the scope is set at. For FFP scopes there is a compromise that needs to be reached in terms of stadia thickness, when the scope is at its lowest power setting the stadia needs to be thick enough to be visible, but you do not want it too thick that when zoomed all the way in it obscures large portions of your target. The ERB-1 MRAD reticle strikes a nice balance for tactical use, it is fairly thick at its highest zoom power, perhaps too thick for precision target shooting, but it is setup nicely for tactical shooting providing a good visible stadia even on dark backgrounds. At the low power it is still easily visible and even the smaller half MIL hash marks are visible at 4x. It should be noted also that there is an ERB-1 MOA reticle that is the same reticle but calibrated in MOA for use with MOA knobs. On the PST scopes, Vortex matches the reticle units to the knob units so you always have a MIL/MIL or MOA/MOA scope.

The optics on this 4-16 Viper PST scope are fully coated with the Vortex XR lens coatings to help with light transmission, and the glass itself is extra low dispersion glass. So what does that mean? Well, the optics are good, about on par with other similar quality scopes, though I would not say that it sets the standard for this class of scope either. There is good contrast and sharpness and the scope gathers light well at dusk and dawn conditions and even in bad weather as we experienced during our shooting evaluations of the scope. We have been asked about the quality of the 4-16x PST glass as there have been some questions about the quality on early samples of the PST, but on this one it was up to the quality we expected. The eye relief for the scope is a generous four inches and it stays quite constant through the entire zoom range which is nice. There should be no issues using this scope with magnum powered rifles.


For the shooting tests we mounted the scope to our standard Remington 700P “test mule” rifle that we normally use for scope evaluations which has a Warne 20 MOA canted base on it. We used some Burris XTR 30mm low rings that we had here to mount the scope to the base. The weather on our shooting day pretty much stunk; it was about 45 degrees with hard rain and 10-15 mph winds. During the tests we did the normal box test, shooting groups at each corner and bringing the 5th group right back to the start on tope of group 1, and the scope tracked well during the test. We also fired a group and then moved the reticle over 5 full MILS on the windage knob and then measured the distance between the groups to determine accuracy of clicks. The groups measured 17.75″ from center of group one to center of group two, where 5 MILs is exactly 18″ at 100 yards. This shows an error of 1.4% which is within the margin of error for our tests give group sizes and weather conditions. Mechanically the scope is sound and accurate.

To conclude, the Vortex Viper PST scope has all the right features for a tactical scope and it has a targeted street price of under $1000. The scope meets those criteria and does provide a good performing offering, but it should be mentioned that $1000 buys a lot of scope and the competition in that price range is fairly stiff. There are very good options from Weaver, Nikon, Bushnell Elite, Burris XTR, and others, and they have similar features and quality for the same or lower price. The Vortex Viper PST is a good offering and quality appears to be good with just a few things we didn’t like and some things we did like. Overall the scope performed well and had the things a tactical shooter needs, it certainly should at least be considered when shopping for a scope in this price range. One thing that does need to be mentioned as well is that Vortex has an excellent, and well earned, reputation of customer service and in today’s world, that itself does go a long way.

Sniper Central – 2011




Aaron Lawrence

I just wanted to say that I am new to the world of tactical scopes, and I recently purchased the Vortex Viper PST 4-16×50. I put it on a Windham .308. I have found it to be everything you say and also very easy for the novice tactical shooter to learn on

Blue 6

Mel, Aaron-

Do you know whether the Vortex Viper PST is nitrogen filled, like their Recon spotting scopes.

I had the chance to test a Recon through an LE grant program and was really impressed… I was deployed at the time and found that bringing our rifles outside (great Leupy Mk 4 scopes) from an AC environment to crazy extreme coastal desert heat (100-120 degs) and humidity (75-90%) would immediately fog them up. They would sometimes take up to 30 mins to acclimate and clear… but not the Recon. It was fog free from start to finish due to the nitrogen fill.

Perhaps this might be minor to some, but if the Viper PST had the nitro fill too, I’d argue this might be the tie-breaker in that competitive price range for a tactical “work” rifle .

I will say while it was great having a milling optic in a small, light, handy package… I don’t much care for the thinner Vortex reticules, especially in low light. Just my 2.

Blue 6

Correction: Vortex Recon is Argon filled… nitrogen is what everyone else uses I think. Sorry.


I have had a PST 4-16 for about 2 yrs now and although the scope is solid and has a lot of features for $700, the optics are a bit dark compared to my hunting Bushnell scopes such as the long range hunting series and my tactical ERS. But, for the money this scope has a ton going for it. As you get into $1000 and up the glass seems to improve on other brands and likely within Vortex’s line as well I suspect. Overall I trust Vortex as a company and have been happy with their binoculars as well.


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