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Join Date: Mar 2008
Location: Brown County
Product Review -- Vortex 1-4x24 Viper PST Optic
A friend recently bought a Vortex PST scope from INGO advertiser A&A Optics. It's an illuminated reticle, 1-4 magnification scope marketed to fill the close quarters to medium-range (0-300 yards) market. Some have suggested that it is a replacement for a red dot sight.
There was an EOTech model 512 on my friend's rifle, so I decided to enlist the help of some other shooters to compare the Vortex PST to the EOTech using this rifle as the host. I wanted to see if the Viper is a direct replacement for a red dot sight or do its features lend itself to a different set of shooting needs.
Approach Used in This Review
This review will look at both the mechanical performance of the Vortex scope and the subjective performance of the scope in both close quarters and longer distance use.
To test the mechanical capability of the components, the scope and mount were put through a box test and a return to zero test.
Additional shooters were enlisted to test the close quarters characteristics of the Vortex scope and a popular red dot scope. A series of five drills were followed by the thoughts and opinions of the guest shooters.
Finally, the two optics were shot at 200 yards to see if either one provided an advantage as the distances increased.
-- I claim no responsibility for the following disclaimers.
-- Any disclaimer issued by me is subject to change without notice.
-- I know that there would need to be numerous additional replicated trials before claiming statistical significance. I don't get paid to do this and ammo isn't cheap.
-- Your results may vary.
-- I would love to compare the Viper against every type of red dot sight ever sold. See above about low pay and pricy ammo.
-- The opinions expressed by the participants are theirs and theirs alone. You may not agree, but you've gotta love them for trying.
-- All rights reserved, but some wrongs are still available.
Vortex Scope Specifications:
Model: Viper PST (Precision Shooting Tactical)
Model No.: PST-43111
Reticle: TMCQ MOA illuminated (Tactical Milling Close Quarter)
Center Dot: 1 MOA
Scope Adjustment: 1/2 MOA clicks
Weight: 16 oz.
Vortex Optics - Viper PST 1-4x24 TMCQ MOA (Capped)
A Switchview throw lever was added to speed changing the magnification.
Selecting a Scope Mount
My friend wanted a quality scope mount that would allow him to quickly remove and later replace the scope. I recommended the LaRue LT-104 Quick Detach mount (30mm). Although pricy, I've had great success with the LaRue mounts.
LaRue Tactical SPR / M4 Scope Mount QD LT104 | LaRue Tactical
A few days after ordering, a box arrived at my doorstep. It had the mount and some other LaRue goodies!
I installed the mount and scope with no problems.
First Range Visit: A Surprising Zero!
I took the Daniel Defense AR to the range to try out the Vortex scope at 50 yards.
This is the typical set-up I use for setting a 50 yard zero.
I selected some 69 grain Sierra Match King rounds driven by 22.5 grains of Benchmark powder. These were rounds I had left over from testing I had done on my own AR to find a good-shooting bullet/powder combination.
The 1x4 scope was set at 4x with no illumination.
Now remember, this is a new scope in a new mount. It's never been zeroed. Very often when zeroing a rifle, I may not even be hitting anywhere on the sheet of paper at first and will have to move closer to the target to find where the rifle is hitting.
Using sandbags, I squeezed the trigger.....
And could barely believe my eyes
I shot again and hit a bit above and to the right of the first round. I adjusted 1 click down and 3 clicks left. (On this scope, each click is 1/2 MOA.)
The third shot was 1/2" high and dead even.
I adjusted 2 clicks down and shot a 4th time.
(*Before anyone lectures me on statistics and the need for more rounds to establish the true point of impact; I get it. I just wasn't going to mess up this phenominal target! )
So, for a new scope and mount, a total of 3 clicks down and 3 clicks left. Amazing!
I credit this primarily to high-quality components in the scope and mount (and probably the upper/rail).
I put in a magazine of 62 grain military green tip 5.51 ammo. I've good success with this in 1/7 barrels. I took three shots at a fresh corner diamond of the target.
They were hitting a bit right.
I was excited so I put on a Harris bipod on a LaRue QD mount and went down the dam a bit to shoot prone at some steel about 211 yards away.
I liked the way this rifle and scope shot!
Hitting the full-sized IPSC target was a snap with this rifle. So I shot at the 45% IPSC target. I hit it and then missed a couple of times. I realized the green tip ammo was hitting a bit right. I adjusted the scope 2 clicks left. (That would be 1 MOA left, about 2".)
Then I aimed at the 25% IPSC target. That is equivalent in size to hitting a full-sized IPSC target at 800 yards. (It doesn't simulate the wind affects and drop of an 800 yard shot.) The 1 MOA center dot of the Vortex reticle was very helpful in making long-distance shots when that isn't this scope's forte.
I was able to hit the smallest IPSC target better than 50% of the time. When I did miss, it was always because I failed to apply one of the shooting basics. This rifle/sight system is quite capable of repeatedly making this shot.
Testing the Mechanical Function of the Vortex Viper PST and LaRue Mount
Any good rifle scope should track well. That means that the mechanical system that moves the internal components that make the point of impact move do indeed move the POI the amount they should. Additionally, any good scope will return to the same impact point when the turrets are adjusted back to their starting point. I used a "Box Test" to determine if the Vortex scope had good internal tracking.
For the mount, I wanted to verify that the point of impact was unchanged when the scope and mount was removed and re-installed. For that, I repeatedly removed and installed the mount while checking the POI to see if it shifted.
These tests were shot at 50 yards off of a bench using sandbags.
The Box Test
Using M855 62 grain green tip ammo, I shot a five round group in the upper left diamond on a standard sighting target.
The upper righthand diamond is 9" away. At 50 yards each 1/2 MOA click should move the point-of-impact 1/4". To move 9" requires 36 clicks Right.
Now here's the odd part. I shot this second 5-round group while aiming at the upper left diamond. In fact, every group I shot was done while the scope was aimed at the upper left diamond.
I dialed in 36 clicks of Down and shot. Then 36 clicks Left and shot followed by 36 clicks Up and I was back where I started.
Just for grins, I dialed in 18 clicks Right and 18 clicks Down and shot 5 more rounds while aiming at the upper left diamond. The results are in the picture.
Accounting for natural variation by the shooter, I determined that this scope passed the box test with flying colors! The internal scope mechanism tracks well and provides accurate bullet placement and repeatability.
For this test I removed and installed the scope/LaRue mount combination 3 times and shot a five round group. Then I removed and installed it another 3 times and shot a five round group. I did this around the 4 outer diamonds of a sighting target.
Using OnTarget software to evaluate the groups, the MOA and location of the group centers were consistent (again taking shooter variation into account). The LaRue mount was very good at maintaining a consistent point-of-impact when removed and reinstalled.
Testing as a Close Quarters Optic
A key area I wanted to test was how the Viper performed compared to a popular red dot optic. Because the rifle already had an EOTech sight on it, I chose to use it for our comparison.
I also wanted to test the Viper's performance in close quarters applications. I decided to call on some others to help me since they had much more experience with close quarters gun handling than I did. I wanted them to spend some time with the two optics and then provide their subjective opinions about the suitability of the Viper optic using the EOTech as an industry standard.
I presented INGO members shooter521 and esrice with this offer. "Would you be willing to come to my range and shoot? I will provide the rifle, the scopes, the ammunition, and I'll feed you lunch. All I ask is that you give me your thoughts and opinions about what you shot during the day." To my surprise, both gentlemen immediately accepted my offer!
INGO member Que joined us part way through the tests and added his thoughts to the summary videos.
Five courses of fire were created. Each one was shot twice by each tester; once with the Viper scope and once with the EOTech. Times were collected for the first four courses. Timing the fifth didn't make sense. Which scope was shot first varied among the courses of fire. Videos were taken of each test and shooter. Don't panic; I'm not going to post every video, just enough to give you an idea of what was done.
The courses were:
Course 1: Four rapid hits on 67% IPSC steel (angled) at 45 feet.
Course 2: Two hits, magazine change, two hits on steel, 45'
Course 3: From standing, lay on your side behind an ATV, place 4 rapid hits on steel, 45'
Course 4: Place two shots each on 5 paper targets at 25'
Course 5: Starting by the pond, place several hits on steel plates across the pond. Run uphill to second stump, engage steel targets in yard. Run further uphill to flag, engage steel targets in yard. Go prone and engage steel targets across pond. This is not timed. Use as many rounds per station as you desire.
I've attached a sampling of videos from the test runs. After the first four courses of fire I've created a chart showing the average run times for the two shooters (all time is in seconds). I acknowledge that I was putting new equipment into a person's hands and asking them to perform with it cold. However, since both my test shooters were operating under the same conditions, I'm hoping the results have some validity.
(Side note. Neither of the shooters doing the testing regularly use the Viper or EOTech optics so we avoided a familiarity bias.)
The steel we used was from Bobcat_Steel. Some may notice that we were shooting rifle rounds at a 67% IPSC target at fairly close range. This target has a significant downward cant to deflect the splatter and handled the rounds without any issue or damage.
Test 1, Viper, shooter521
Test 2, EOTech, esrice
Test 3, Viper, shooter521
Test 4, EOTech, esrice
Test 4, Viper, shooter521
Test 4, EOTech, Que
The results of the testing indicate that for three of the courses of fire completed, the EOTech was faster than the Viper. One one test, they were even. Dot acquisition was faster with the EOTech reticle. This is likely due to the larger screen/field of view of the EOTech scope.
One shooter reported that he found his eyes wanting to treat the Viper like a traditional rifle scope and his non-dominant eye wanted to close. Additionally, his focus was wanting to go to the reticle rather than the target. This made it hard for him to shoot in the desired both-eyes-open approach.
Test 5_Run and Gun
After the timed tests, we transitioned onto a sloped yard area so the shooters could move through several dynamic transitions to allow them to evaluate the two optics with more movement. The video doesn't do justice to how steep it is running up the slope!
After the day's tests were done, I asked the three shooters to consider their experience with the Viper and to compare it to the EOTech and to red dot sights in general.
The summary is contained in two videos.
QD - Quick Disconnect Mounts
Shooter521 created a brief introductory post about the utility of QD mounts, in particular the LaRue line of high-quality mounts.
It can be found at: QDMountVideo
The Viper scope looks heavier than the red dot EOTech; but how much? So I weighed them with their mounts!
The Viper weighed in at 22.1 ounces and the EOTech at 14.5 ounces. (Just an FYI, the Aimpoint Micro and mount weigh 6 ounces.) The EOTech is 2/3 the weight of the Viper. If every ounce counts to you, the EOTech certainly has the advantage.
Out in Public!
I took the rifle and Vortex optic to a rifle shoot in southern Indiana in early November 2012. I asked two INGO members to shoot the rifle at steel targets at 100 yards. Here's jrainw giving the combination a test.
Both he and DaKruiser liked the scope and made 100 yard offhand hits on a variety different steel targets. They noted the very clear glass of this scope. I shot it as well and had the same experience.
With the close quarters comparison of the Viper versus the EOTech done, I wanted to take the rifle and shoot it at a longer distance. This is by no means 'long' distance. Just a bit longer than you normally think of for red dot sights. (I know I'm going to hear from all the red dot shooters now...)
The Viper scope is trying to do two tasks, close quarters and longer distance. So I wanted to see if it had any advantage over the EOTech scope at just over 200 yards.
I shot at both steel and paper targets at 211 yards. I was set up in a prone position and used a front sandbag. I used M855 ammo for this test.
[It was 38 degrees F with a moderate and variable wind swirling around.]
Using the Viper scope set at 4x magnification, I shot a few rounds at the full-sized IPSC steel target to confirm my zero and then shot 10 rounds at a paper sighter target. The OnTarget software said I had a 3.9 MOA.
I shot 5 rounds at the 45% steel IPSC target and hit it 3 times.
The illumination switched off several times (was seen earlier). I was able to get it running by moving the switch cap back and forth. [See updated info in Conclusions section below.]
I switched to the EOTech scope (1x) and shot 10 rounds at a fresh sighter target. This time I had a 3.6 MOA group. Very similar to the Vortex group. I would need to shoot this test many times to be able to state whether there is a true difference between these.
I shot 5 rounds at the .45% IPSC target and hit it 2 times.
I shot 5 rounds at the head of the full-sized IPSC steel and hit the throat area 4 times.
The non-magnification of the EOTech makes it harder for my old eyes to see the target, but the sight is able to return accurate results.
I re-installed the Viper scope and set it to 1x magnification. At this setting the front sight post is very visible, but doesn't detract from the use of the scope. I could easily watch the doe walk in front of the target stands as I was about to shoot this string of rounds.
I hit the 45% IPSC steel and noticed that the glass in this scope is very good as it continued to gather light in the rapidly approaching dusk of the evening.
The two scopes performed equally in my opinion. Both are quite capable of making hits at 200 yards. The Viper has a small advantage for me and my eyes as the 4x magnification feature makes it much easier for me to see the target I'm shooting at. If used for hunting, this would be a large advantage.
Conclusions About the Vortex Viper PST Scope
-- High quality glass provides good dawn and dusk light gathering.
-- The internal optics mechanisms track well and make this scope repeatable.
-- Controls are easy to operate and turret clicks are crisp and accurate.
-- It's a true 1x scope when set to the single power setting.
-- Magnification feature allows for easier target identification and more precise hits, especially at longer distances. This would be particularly helpful for hunters and shooters wanting more precision at distanced beyond the normal envelope for red dot sights.
-- The 1 MOA center dot aids in making precise shots possible.
-- The positioning of the eye/head is more critical and less forgiving than other red dot sights.
-- The Viper is very slightly slower to bring into action due to the head positioning constraint.
-- The scope is heavy compared to other red dot optic systems.
-- The failure of the illumination switch was annoying. However, Vortex has an outstanding warranty program and will certainly correct this once they are aware of it. [Update: The dealer has contacted Vortex. A redesigned battery cap is being sent. I'll continue update this article once it has been tested.]
Is the Vortex Viper a 100% replacement for both a red dot scope and a rifle scope? No.
It can do well in both applications, but if you require the very fastest CQB optic, then a red dot will likely serve you better.
If however, you want a single scope that is still very capable at short distances and will give you rifle scope performance out to around 300 yards, then take a look at the Viper. It's a well-built unit that will serve its owner for years to come.
I want to give a big thank you to: shooter521, Que, esrice, andFenway for the use of their equipment, time, talent, and experience. It was fun working with you all to pull this review together.
Last edited by lovemywoods; 12-03-2012 at 12:05.. Reason: Add info on the illumination switch.
Roleplayer / Marketing Guy
Join Date: Jan 2008
Location: Southside, Indianapolis
Excellent review! Thanks for taking the time (many hours, literally) to put this all together in one concise review. I had a blast during the red dot comparison testing!
For me and my shooting I will stick with red dots. But the Vortex Viper PST 1-4x is a very capable optic and I enjoyed getting a chance to play with it.
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Join Date: Feb 2010
Beautiful setup! I just got the MRAD version of that scope set in the same mount.
I've only gotten to put about 12 rounds down the pipe so far, can't wait to get more time behind it.
FWIW, what drove my choice is that I've got it mounted on top of a .300blk and I want something to dial in drop when shooting subsonics which is something no red dot I could find does easily.
Join Date: Oct 2008
Location: south of richmond in
Great review. All the point made here are very valid. Just a note from MY personal shooting style. I dont have near the time behind a reddot as esrice, shooter, or que. 99% of my shooting and training is done with a scoped rifle because my training is more precision driven than most peoples. For me and my experiance I dont have the issues with the eyebox that are mentioned, but being more precision rather than speed im usto having my head in the exact same position every time. Im not saying this is right, wrong, or indiffrent, this is just the view of a shooter who rarely spends time behind a dot and always spends time behind a scope.
Amazing review folks