HIGH-POWER VS. LOW-POWER SCOPES: DOES MAGNIFICATION MATTER?
WHEN SHOOTING LONG DISTANCE, IT SEEMS LOGICAL THAT USING A HIGHER MAGNIFICATION SCOPE WILL AUTOMATICALLY IMPROVE YOUR PRECISION AND THEREFORE, YOUR HIT RATION OR GROUP SIZE. WE TEST THAT THEORY TO SEE IF HIGH MAGNIFICATION REALLY MATTERS.
In long-distance shooting, it seems logical that higher magnification will automatically improve precision. But how much impact does it really have?
All of us long-range shooters have heard the old adages, “Aim small, shoot small,” or “In order to shoot it, you have to see it.”
If you have ever attended an NRA F-Class 600or 1,000-yard rifle match, it’s common to see scopes that top out in the 50-to-60 power range on the firing line. Weather conditions play a huge role in the power you can dial up to due to the amount of light needed for anything above about 30x— not to mention the effect of mirage. The real question is, Does having a high-powered scope really help you shoot better?
In order to answer this question, I decided to test the theory, so I’d need to round up some really nice hardware and hit the range. For starters, I needed a high-end scope—one that is, without question, at the top end of the optics world. In order to get the ideal scope for the test, I contacted OpticsPlanet.com and explained what I was doing. This company sent me one of the most respected scopes on the market today: a Schmidt & Bender 5-25X56mm PM II PSR scope; this one, the Limited Edition model.
For a test such as this, I needed a special rifle capable of delivering long-range accuracy not possible with most factory guns. I decided that a full custom build from Stewart Rifles in Oklahoma would be the ticket. This one is a proven tactical rifle that has even shot some impressive scores in F-Class matches, for which each relay consists of 20 shots at 600 yards for record. This full custom gun is built on a Surgeon 591 short action chambered in 6.5x47mm Lapua.
Next, I needed very accurate ammunition, so I looked no farther than Lapua, whose ammo and brass are used throughout the competition rifle community. As a result, I knew the ammo would be suitable for the strict test I was planning.
As with any “test,” the design often dictates the outcome, so I did everything possible to eliminate variations in the conditions and setup to minimize their effects on the test.
In order to ensure everything was setup for success, I mounted the scope and leveled it on the Stewart-built rifle with Vortex precision-matched billet rings in 34mm. These rings are matched in pairs at the factory and do not require any additional lapping.
Once at the range, I used a massive SEB rifle rest that is commonly used in benchrest and F- class shooting, as well as a large Edgewood rear sandbag with ears to support the stock. All the shooting was done with a LabRadar unit (MyLabRadar. com) so I could capture the velocity data.
PUTTING IT TO THE TEST
After bore-sighting the scope, I took it to the range and zeroed it at 100 yards; this took exactly three shots using the builtin ranging ability of the scope. After the three fouling/sighting shots, my personal handloaded ammo (40.6 grains of H4350 behind a Berger 140-grain hybrid with a CCI 450 primer) produced a five-shot group of .406 inch. Next, the Lapua ammo shot an even more impressive .370 inch, five-shot group.
I wanted to evaluate the turrets on the scope, so before I began testing, I constructed a 100-yard, 5mm box test and shot three shots after dialing to each corner of the box. I then returned to the zero at the bottom center of the target. As expected for a scope of this quality, all the shots landed exactly on the mark, and it returned exactly to the original zero point. I decided to shoot two five-shot groups at 5x and then repeated at 10x, 20x and finally at 25x, which is the maximum power for this scope. I started this test at 300 yards, repeated it at 400 yards and once more at 500 yards. For targets, I used a 12 x 12-inch bullseye target with a 1-inch red center dot. Normally, the target is not an important part of the test. However, with mine, it was important because of the 5x magnification I tested. When shooting at the 400- and 500yard distances with only 5x magnification, it was somewhat difficult to discern the exact bullseye. Therefore, the target size, color and shape became important.
I had a limited amount of ammunition, so I elected to shoot each bullet weight at a given distance. At 300 yards, I used the
Lapua 123-grain Scenar; at 400 yards, I used the 136-grain Scenar-L; and at 500 yards, I used the 139-grain Scenar.
As a result of this format, I can’t really compare the results at 300 yards to that at 500 yards, because the ammunition was different. You will see that all the groups were very good, with only one five-shot group exceeding 1 MOA out of the entire test; and the overall average of all distances and magnifications was a solid .650 MOA.
Overall, this ammunition was very consistent. I used the LabRadar chronograph (with Bluetooth) to capture and analyze the data produced. Looking at the data in the chart (Chart 1), from the 139-grain ammo, you can see the velocity, standard deviation and extreme spread. Anytime you obtain standard deviations in the single-digit range, you know the ammo is very good and that it will shoot better because of its lower vertical spread, especially at distances beyond 500 yards.
ONLY 5X AT A 1-INCH BULLSEYE AT 300 YARDS WASN’T EXTREMELY DIFFICULT, BUT IT WASN’T EXACTLY EASY OR FAST.
When shooting at the range, the author used an SEB NEO coaxial front rifle rest to ensure he had the most stable and repeatable platform possible. The rest and the scope were equipped with bubble levels to further ensure repeatability and accuracy of the author’s setup.
This target was shot at 500 yards with the magnification dialed to 20x. The group measured .502 MOA.
Here is one of the300-yard groups the author shot at 5x magnification. This one measured a scant .416 MOA. The other group atthis distance and magnification was.442 MOA.
On the Surgeon 591 rifle action, the scope rail and recoil lug are machined into the one-piece receiver body. This not only strengthens the action, it also ensures the 20 MOA scope rail is perfectly in line with the receiver and that the recoil lug is strong, stable and flat. The bolt body is also machined from a one-piece blank to ensure the handle doesn’t break off in extreme conditions.I
Surprisingly, theauthor’s best group of the test didn’t occur at the shortest distance—itoccurred at a high scope magnification (20x). This was shot with the excellentLapua 136-grain ammo at 400 yards and measured .278MOA.