Optimal scope setup



Author Topic: Optimal scope setup  (Read 1226 times))

Online nervoustrigger

  • GTA Senior Contributor
  • ******
  • Posts: 6122
  • The Grin Reaper
    • My youtube channel
  • Real Name: Jason
Re: Optimal scope setup
« Reply #40 on: November 29, 2018, 11:40:29 AM »
Sorry, one more thing :)

After thinking on this some more, it occurred to me perhaps part of the difficulty is a tendency to visualize the reticle more as a physical thing inside the scope tube.  Well, it is but the way it operates is something else.  Instead try thinking of it as a projection...something of a hologram projected onto the target.

That is the manner in which our two hypothetical scopes have identical points of aim.

Offline bandg

  • Expert
  • *****
  • Posts: 1173
  • yes
Re: Optimal scope setup
« Reply #41 on: November 29, 2018, 12:47:22 PM »
Jason, what you just said is plain silly-"the bore is fixed"?  Fixed in relation to what?  You say the scope is not fixed (each of the scopes is tilted differently) but the bore is fixed?  I described a level line of sight to make it easier to visualize the bore to scope relationship.  Neither bore nor scope is "FIXED".  Move one and the other moves because they are rigidly bolted together.  If the scope is held level, the bore(s) tilt upward.  If the bore is held level, the scopes(s) tilt downward.   Neither the bore nor the scope is "fixed" in relation to the world.  They are fixed only in relation to each other via rigid mounts.  And the line of sight and the bore line must converge as they move away from the rifle or you would never have a zero at the crosshair.  You would have a pellet flight that starts below the point of aim and falls away from it.

"The bore does not tilt upward differently for one scope versus the other scope".  Really?  Do you really believe that?  It is nonsense.  And the way I describe a level scope (the line of sight from eye to target) was only to make that easier to visualize.  I never stated anywhere anytime in any manner that the scope was fixed.  But the bore is not "fixed" either.  The line of sight can be upward, downward, left or right.  It depends on where you are standing and where your target is.  The bore is not "fixed".  The scope is not "fixed".   But they are bolted together and move together.  It is just easier if you fix one (either scope or bore, doesn't matter) MENTALLY so the change is easier to visualize. 

One last time for folks to try to visualize this.  Look at one of the horizontal lines running across the page you are viewing.  Let that represent line of sight/what the shooter sees through the scope/your aim line.  Imagine the shooters eye is at the left end of the line looking through the scope but you are standing 90 degrees to his right looking at the scene from the side.  That is the foundation of this example.   Looking through the scope, the shooter sees the target with the crosshairs directly centered.  Perfectly aimed.  But where is the bore?  You can do this with just an unmounted scope in which case there would not even be a bore to consider.  But the shooter would still see exactly the same thing when looking through the scope-the target and the crosshairs.  Now mount a rifle to that scope.  While looking through the mounted scope the shooter still sees exactly the same thing-target with crosshairs centered.  The rifle is on the left with the shooters eye and the target is at the right end of the line.  Take a straight edge and start 1" below the left end of the line (this represents a "low mount" with the scope closer to the bore) and line it up with the right end of the line.  That is how a scope must physically pair bore to line of sight in order to make a projectile hit the target.  Before Jason says it has something to do with the optics in the scope, realize that you can change the turrets to effect this tilt (internal correction), you can physically shim one end of the scope to effect this tilt (external correction), you can use adjustable mounts to effect this tilt (also external correction) or you can use a tapered mount to effect this tilt (again external correction).  It doesn't matter how the correction is done, it only matters how the LOS and the bore are made to approach each other toward the right side.  Realize that using any of the correction methods, the view through the scope from eye to target will still be exactly the same.  The example only illustrates the RELATIVE scope/LOS to bore tilt that must be present in order for the projectile to hit the target.  NOW NOW NOW move the left end of the straight edge down another inch (now it's 2 inches below the horizontal line).  This represents a "high mount" with the scope further from the bore).   While keeping the right end of the straightedge on the right end of the line, lower the left end to that new point.  Now once again the scope/LOS and the bore are pointing at the same spot on the right, the original target.  It must be so in order to hit that target.  Do the two lines slope the same?  Absolutely not.  The lower line (high mount) slopes more steeply toward the LOS than does the middle line (low mount).  The scope/LOS to bore angle is different for the two height mounts.  Neither scope nor bore is "fixed" in the world but they are attached and thus "fixed" only in relation to each other.  That's all I have to say on this.  It isn't really that complicated but one must grasp the basic concept.  I will post no more on this topic thread but will gladly respond to PM's if anyone wants to discuss it individually.  Good shooting to all.
« Last Edit: November 29, 2018, 12:58:41 PM by bandg »
  • Hensley, Arkansas

Online nervoustrigger

  • GTA Senior Contributor
  • ******
  • Posts: 6122
  • The Grin Reaper
    • My youtube channel
  • Real Name: Jason
Re: Optimal scope setup
« Reply #42 on: November 29, 2018, 01:38:13 PM »
Jason, what you just said is plain silly-"the bore is fixed"?  Fixed in relation to what?

It is fixed in relation to the two scopes...the two scope bodies, anyway.

Your contention is that the two scopes give a different error, thus we have to look at what happens when we adjust each scope relative to the bore.  That's why the bore is "fixed".  After all, if we had those two scopes mounted on a rifle, that's exactly what we would do.  We would sit down and zero each of them to the same range. 

If we could angle the bore independently of the two scopes, everything is not rigidly affixed...a condition which you raised yourself:

But they are bolted together and move together.

I'll concede the use of "fixed" here is weak but we seemed to be using the term in the same fashion.  Again, you were explaining the scenario where you have to angle the barrel differently to make the trajectory coincide with each of the two scopes.  We don't angle the barrel, we angle the scopes...more specifically, we angle each of their erector tubes so their reticles--their "projected" representations--align exactly to each other against the target.

And as I've been saying, if the reticles lie on top of each other, there is no way for their errors to differ.  I frankly don't understand how you can acknowledge that to be true but continue to argue that they differ.

Lastly, it's rather unbecoming to continue to call people wrong and refer to their arguments as "plain silly" and "nonsense", particularly when you find yourself in a situation where there are at least 4 knowledgeable people calmly attempting to help you understand why this is so.

Offline rsterne

  • Member 2000+fps Club
  • Bob and Lloyd
  • GTA Senior Contributor
  • *****
  • Posts: 21222
  • GTA Forums Person of the Year 2017
    • Mozey-On-Inn
  • Real Name: Bob
Re: Optimal scope setup
« Reply #43 on: November 29, 2018, 02:38:22 PM »
Quote
Lastly, it's rather unbecoming to continue to call people wrong and refer to their arguments as "plain silly" and "nonsense", particularly when you find yourself in a situation where there are at least 4 knowledgeable people calmly attempting to help you understand why this is so.

^X2, and why I dropped out of this thread.... 'nuff said....  ::)

Bob
  • Coalmont, BC, Canada
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsenal:
1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine, 2260 HPA (37 FPE), 2560 HPA (52 FPE), .22 QB79 HPA, Disco Doubles in .22, .25 & .30 cal, "Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, 7mm, .308 & .357; Mk.III is .410 shotgun and .458 cal), .257 "Monocoque" Bench PCP, 6mm Regulated PCP and .257 Unregulated, Three BRods.

Offline Scotchmo

  • Expert
  • *****
  • Posts: 1546
  • Real Name: Scott Hull
Re: Optimal scope setup
« Reply #44 on: November 29, 2018, 04:51:52 PM »
Gun-cant happens when the gravity vector no longer lies in the trajectory plane. Gravity must be part of the equation.

Gun-cant has nothing to do with the shooters viewpoint. Scope does not matter.
  • Los Osos, California

Offline Yogi

  • GTA Senior Contributor
  • ******
  • Posts: 2595
  • yes
  • Real Name: Yogi
Re: Optimal scope setup
« Reply #45 on: February 16, 2019, 11:47:40 PM »
Sorry but when I try to quote these posts it puts my comments in as part of your post.  I see what you are saying-assuming the rifle is canted.  But how about aim high but don't cant. :D

Space down past the last [/quote] marker. ;D

-Y
  • San Francisco, CA
Hatsan 95 Vortex, .22
RWS 6G, .177
RWS LP8 Magnum, .177
Diana 340 N-Tec, .22 Compact Lexus
HW 50S, .177 and/or .22

GTA - What's been your success with air gun target practice?
 

Sponsored Ad: