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.

Gun World - - Contents - By E. Don Smith

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?

THE EQUIP­MENT

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.

THE AMMO

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.

SHOOT­ING WITH

ONLY 5X AT A 1-INCH BULLS­EYE AT 300 YARDS WASN’T EX­TREMELY DIF­FI­CULT, BUT IT WASN’T EX­ACTLY EASY OR FAST.

I

I

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.

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