SCOPES, EXTERNALLY ADJUSTABLE

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joeb33050 posted this 01 May 2019

 

SCOPES, EXTERNALLY ADJUSTABLE

 

            Warren page wrote that the externally adjustable scopes hinder accuracy.

 

            I have been shooting my BSA Martini, 50 yards, 5-shot groups, GECO Semi-Automatic ammunition, with three different scopes. Here are the records:

 

30X Lyman STS, 30 groups, .534” average group size

 

Tasco # 705 Externally Adjustable, 6-18, 4 targets, 40 groups, .481” average group size

 

Weaver T36, 80 groups, .429” average group size

 

            While that Lyman/Unertl/Fecker/Litschert/Davis scope may look good on a rifle, maybe it is causing some inaccuracy.

 

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RicinYakima posted this 01 May 2019

Well, I'm reasonably sure they are mechanically less accurate. But how often do I need that slight advantage? Especially when it makes the old rifle look so ugly? I'm not going to drill holes in my 22LR 1927 Springfield Armory M1922 to put a modern 3X40 variable with an 60 MM lens on it.

If you are going to play the match game, you need the best you can get to test ammo and your shooting. For plinking sage rats at 25 to 75 yards, I'd rather look and feel "cool" shooting in my campaign hat. Yes, I've shot CBA matches with Lyman and Unertl scopes, but wasn't trying to win, just have fun with the shooting buddies.

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Brodie posted this 01 May 2019

Ric,

Please educate me.  I fail to see why an externally adjustable scope would be inherently more inaccurate than one where you took the cap off and changed the sight with a coin.  Or is this whole thing just so Joe can brag about his group sizes?  Isn't all you are doing is turning a screw?

B.E.Brickey

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loophole posted this 01 May 2019

I suspect that ifmounted  everything else is equal a scope which has bases mounted closer together would have a slight edge over one with bases mounted on barrel and receiver, regardless of whether the adjustments are internal or external, but I never had any way to test the theory. I have a Unertle  untra varminter 15 power.  I have tested it many times against against Leupold scopes on several different rifles and the leupolds  never got smaller groups.  Same with a Unertle 20X. I suspect there are scopes a lot better than any I tested, and some of them probably will shoot better than any of the mine.

I am satisfied that a better benchrest shooter than I would shoot better groups than I ever did with the same rifle, regardless of which scope he used.  I now have the ultra varminter mounted on my 1939 Mod 70 30-06, and no scope I could put on it will let me outshoot it.  Even if it did, the Unertle is so pretty. . . .

Loophole

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RicinYakima posted this 01 May 2019

B.E.

There are two issues with externally adjustable scopes. The first, while the scope tube and lens are good, the adjustments are dependent upon a perfectly straight tube with not even a couple of thousandths bend. Long tube will heat in the hot sun and bend from different expansion. As the scope wears under the knife edges, it has to be back at exactly the same point of wear, or it will point to a different spot. Even putting a thick coat of grease on the scope will change where it looks as it slides back and forth.

The minimum spacing between mounts is 6 inches, and that is for 50 foot indoors. Most are set at 7.2 inches apart, so one goes on the action and one on the barrel, upsetting barrel vibrations. While not so bad on 22's, at the recoil levels of 30/06 it is a major factor.

So while it is small, Joe's is 0.10", matches are won or lost by less than that.

HTH, Ric

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Tom Acheson posted this 01 May 2019

This theory is new to me.

I have a Remington Rolling Block that is being rebarreled (.38-55) which I just found a scope for, a Unertl 24X 2".

What we do isn't science, its a hobby, a recreational outlet. We shoot for enjoyment and maybe along the way we have a good day. The small differences between two scope designs aren't likely to be obvious for most of us. When are exposed to a new (to us) rifle, what do we look at first?...the overall appearance of the gun, the wood and the metal fit to wood. An old style rifle deserves a period correct looking scope.

FWIW

Tom

 

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Brodie posted this 01 May 2019

Thank you Tom,

Now I understand what you mean by: "externally adjustable", The adjustments are not on the interior of the scope, but outside of it moving the entire scope around.  What I thought you were talking about was external knobs on the adjustment turrets so you did not have to take the cap off. 

With all of that cleared up I can see why "external adjustment " could and most likely does introduce some error in alignment.

Rick, the first ultramicrotomes were just a bar of steel with a holder for the specimen on one end that went up and down, and a goose neck lamp with a 100 watt bulb which was moved closer or away from the bar to increase or decrease the thermal expansion of the metal and control the thickness of the sections; preferentially around a thousand Angstroms.

Tom, I agree that an old rifle deserves a period appearing sight either glass or iron.

 

B.E.Brickey

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joeb33050 posted this 01 May 2019

Some famous gun guy said that only accurate rifles are interesting. I've sold a lot of accurate rifles, because they had no magic. Magic rifles include BSA Martinis, Borchardts, Springfield 03's and Trap Doors. Only accurate rifles with magic are interesting.

For me, no Remington 700 or even 40X, has any magic at all. 

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gnoahhh posted this 02 May 2019

The validity of external adjustment target scopes is something I've always taken on faith. This comparison is interesting, and something of an eye opener. However I have no intention of A) drilling more holes in my rifles so as to run comparison tests to prove/disprove to my own satisfaction, and B) such scopes as Unertl, Fecker, Litschert, etc. completely satisfy me.

My mainly pre-war rifles (and/or copies thereof) would just look dumb with a 36X Leupold on them. Imagine, if you will, my M1903A1 USMC sniper with a Hubble telescope on it versus its 8x Unertl...

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Tom Acheson posted this 02 May 2019

Probably need to keep in mind that the guns used, the number of groups fired and the scopes that were used, is a small and limited population. While the conclusions developed may be OK for the test described, it is not something us observers can identify as fact. 

There are just too many variables at play. For example, maybe all of the groups were fired in the same weather conditions of heat, light, wind, etc. That's one busy day at the range, (150) groups! If all were shot in one session, how does shooter fatique factor in?  Using the Houston warehouse would help ameliorate this.

However, if these groups were shot over a series of several range trips, the one thing that many of us match shooters can easily overlook is the fact that an idividual is a "different" person on each of those range trips. Lots of life's daily activities affect each of us mentally. The brain is thinking about those influences while its trying to concentrate on the shooting tecnique. That differential affects how we perform at the shooting bench and consequentially influences the results.

Tom

 

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R. Dupraz posted this 02 May 2019

Well said Tom

 

R. 

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joeb33050 posted this 02 May 2019

"you can lead a horse to water,..."

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RicinYakima posted this 02 May 2019

Tom, You will get no disagreement from me on your post. But when I look at the modern reticle cell that only has 0.060" movement in two 360 degree holders, under constant spring pressure and floating in a 100% argon bath, it should be very steady. A steel tube 14 to 18 inches long, riding back and forth in dust, dirt, rain then put into a box, at best, or stuffed into a gun case has a lot tougher life. Just counted up I have seven of external adjustable, would never sell one off my old rifles, but if I wanted to win a benchrest match with a bolt gun, it would have an internal adjustable scope.Ric

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Bud Hyett posted this 03 May 2019

Many years ago with an exceptional lot of Fiocchi Pistol Match, a BSA Martini International Mark 1, Lyman Super Targetspot 20X, and a windless morning at Tacoma Rifle and Revolver, I set out to experiment with the external adjustment scope.

My uncle had impressed on me his methodology for using these scopes. He was a high-power shooter who loved 600 and 1,000 yard matches. His rifle was a custom .30-.338 blown out to the neck angles of a .22 K-Hornet and a Lyman 25X Super Targetspot for "Any Sight" matches. He was a fastidious record keeper and experimenter. He believed:

  • There were enough manufacturing differences in individual scopes within a brand and model that a shooter should experiment and trade for better scopes.
  • The recoil spring should not be used, pull the scope back with an even pull after each shot. 
  • Then twist the scope counter-clockwise to pull it into the same position for each shot.
  • A dial indicator on the scope against the rail will show .001 to .002 inch movement on a well-used scope.
  • The front mount and guide rail relationship had the same wear and the twist moved it against one side also.

The morning was spent shooting ten-shot groups at 100 yards varying the parameters. The results were inconclusive. The one extreme of recoil spring tight and no twist of the tube versus recoil spring loose and twisting the tube against the mount was not significant after five separate groups each. All were sub-minute which this combination was capable of producing. 

I have four external adjustment scopes and four adaptor mounts to use internal adjustment scopes on external mounts. Serious matches require every advantage. Traditional matches require external adjustment scopes and I comply. External adjustment scopes are great and enjoyable within their limitations. And they do look good on older rifles. Before I had the Unertl scopes, I put a Redfield 3200 on a Browning 1885 to fake the appearance.

And I still twist the scope tube before each shot. 

 

 

Farm boy from Illinois, living in the magical Pacific Northwest

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Pentz posted this 04 May 2019

Although ithe 30x STS may be inherently less accurate, to my mind and eye a March, Nightforce or Vortex just looks wrong on a CPA.

Heck, the wind messes with me more than scope quality.

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