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Question about turret backlash

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Category: Scopes
Forum Name: Rifle Scopes
Forum Description: Centerfire long gun scopes
URL: http://www.opticstalk.com/forum_posts.asp?TID=44927
Printed Date: August/23/2019 at 11:18
Software Version: Web Wiz Forums 12.01 - http://www.webwizforums.com


Topic: Question about turret backlash
Posted By: tpcollins
Subject: Question about turret backlash
Date Posted: June/14/2018 at 09:10
I understand turret backlash, but still have trouble knowing if a scope's turrets are CW or CCW if they don't have a target knob to see which direction it's moving. If I have to turn the knob CCW and out, I'm moving the turret's screw away from the erector tube and spring. To prevent backlash on an inexpensive scope, it's recommended to go a few more CCW clicks past the intended amount and then come back that amount to finish up pushing against the spring.

If the bullet's POI needs to be moved up, the crosshair needs to be pushed down so when the rifle is elevated for the new crosshair position the poi hits higher. But turning the turret CCW would seem to lift the reticle up instead of down. 

If this is correct, how does turning it CCW (or out) move the reticle down?  Thanks.


 



Replies:
Posted By: Rancid Coolaid
Date Posted: June/14/2018 at 10:54
Some scopes are CCW, some are CW.  I haven't seen a modern scope that has no markings whatsoever.

Forget about the erector, look at the markings - and, as Reagan said, "Trust, but verify."

For clarity: there is a HUGE difference between an inexpensive scope and a crappy scope.

And Leupold is famous for the need to dope beyond then come back to the right change, even their high-end stuff.  Maybe they've fixed it, maybe not, I don't care, I don't buy Leupold products.


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Freedom is something you take.
Respect is something you earn.
Equality is something you whine about not being given.


Posted By: GiantGreg
Date Posted: June/14/2018 at 13:32

My best guess would be that CCW vs CW would be  that one is using left hand vs right hand cut threads.

If you are wanting to crank knobs then you need a scope with some marked target knobs.

If you want to crank and accurately get the right angular adjustment, then that comes with a price. You can put a spoiler on geo metro, but it won’t make it perform like a F1.



Posted By: tpcollins
Date Posted: June/14/2018 at 14:59
Originally posted by GiantGreg GiantGreg wrote:

My best guess would be that CCW vs CW would be  that one is using left hand vs right hand cut threads.


On most of my scopes, CCW for up elevation looks to be turning the turret "screw" out and moving the erector away from the spring. 


But to move to POI up, it would have to push the crosshairs down. Is this because the erector is in the middle where the image and crosshair is upside down and hasn't been turned right side up yet at the ocular?  Thanks.



Posted By: Rancid Coolaid
Date Posted: June/14/2018 at 15:58
 I don't spend much time worrying about how sausage is made, I just eat.

If you are unsure, you can always anchor the gun, pointed at a grid, and turn the elevation turret and watch what happens.  I have a bore sighter and do just that when installing new scopes.  It will show movement direction and distance.


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Freedom is something you take.
Respect is something you earn.
Equality is something you whine about not being given.


Posted By: tpcollins
Date Posted: June/14/2018 at 16:16
You're missing the main point Rancid - I want to know for sure on scopes without target turrets if up elevation on a CCW turret moves the erector up AND AWAY from the spring. 

If I need to adjust up elevation or right windage, then whatever adjustment I need to make, I want to go past a couple extra clicks and then come back into the spring that same number of extra clicks. It's as simple as that. 


Posted By: Rancid Coolaid
Date Posted: June/14/2018 at 16:59
I get it,but is this a problem or a potential problem?

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Freedom is something you take.
Respect is something you earn.
Equality is something you whine about not being given.


Posted By: GiantGreg
Date Posted: June/15/2018 at 06:34

 I think your over thinking this. Knowing and understanding the internal mechanics are irrelevant. I think what you are actually wanting(whethere you realize it or not) is a tall target test.
CLAMP that thing down TIGHT!!!!!!!  hang a yard stick and 100 yards and make an adjustment.
If you find that the clicks you turn equal out to what it should be on the yard stick, your good. IF your off, you  can dial past and come back to check for lash.

If you dial 5, and get 5 then dial 10, 15, etc. If your off, then your off. It either tracks or it doesn't.

 



Posted By: tpcollins
Date Posted: June/15/2018 at 07:43
Originally posted by GiantGreg GiantGreg wrote:

 I think your over thinking this. Knowing and understanding the internal mechanics are irrelevant. 

 


That may be for you, but not for me. Whats wrong with wanting to understand how something works? 

It's not rocket science to realize if you need up elevation to have a poi hit higher on the target. But that action involves the erector tube to lift up, this is contradictory to moving the reticle's crosshair down to accomplish a higher POI.

The only solution I can think of is because the image is upside inside the erector tube and up is actually down - Occum's Razor? All I need is a yes to confirm that, and if it's not, please explain that as well. Seems like a simple request to me.


Hopefully Koshin can chime in.



Posted By: Rancid Coolaid
Date Posted: June/15/2018 at 09:55
 So... this is a theoretical unmarked turret and this has been a purely academic discussion?

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Freedom is something you take.
Respect is something you earn.
Equality is something you whine about not being given.


Posted By: tpcollins
Date Posted: June/15/2018 at 11:46
I just want to understand the mechanics behind the raising of the elevation turret that allows the erector tube to lift also - but the crosshair has to move down to raise the POI. So do YOU know if that's because the image is upside down in the erector and up is really down?

I don't mean to be rude but if you can't answer that question I don't need a reply to something that doesn't relate to the question. Obviously you don't know either or you would have explained how it works. Confused


Posted By: tpcollins
Date Posted: June/15/2018 at 14:09
I sent an email to a contact at Vortex and he explained exactly how it worked. I'm all set.


Posted By: koshkin
Date Posted: June/19/2018 at 12:15
A couple of points on the backlash issue.

Generally, regardless of whether the turret is CW or CCW, the erector is moving in the same direction for adjusting up.  The threaded stem will have different threading for different turrets.

If you are worried about backlash, you should be worried about regardless of the direction of the adjustment.

ILya


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Posted By: tpcollins
Date Posted: June/19/2018 at 14:14
Thanks Koshkin, if the erector moves up for UP elevation with either a CW or CCW turret, I can prevent any potential backlash from now on.


Posted By: koshkin
Date Posted: June/19/2018 at 14:22
Why does it matter to you if the erector is moving up or down?  If the system has backlash, it will be there in both directions.

ILya


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https://www.instagram.com/darklordofoptics/ - Instagram


Posted By: tpcollins
Date Posted: June/19/2018 at 16:26
Originally posted by koshkin koshkin wrote:

Why does it matter to you if the erector is moving up or down?  If the system has backlash, it will be there in both directions.

ILya

According to the bench rest shooters, UP and RIGHT moves the erector tube AWAY from the spring. They say if you need 6 clicks UP elevation, then go 10 clicks UP and then DOWN 4 clicks so the turret ends up pushing against the erector - and especially the spring. Right, wrong, or indifferent - they claim it eliminates waiting for the scope to "settle in". And that's what I do.

A lot of us use something to tap on the turret afterwards as an extra step to eliminate the need for the scope to settle in (backlash), as I don't like wasting ammo when I'm at the range.

All of my scopes seem to have CCW turret for UP elevation, but I have a Zeiss Duralyt the is CW for the UP elevation - actually it's an ASV target turret that doesn't go up or down when turning -  which is why I was wondering if the erector moved up for UP elevation on both CCW and CW type turrets.

Since I've learned how the erector tube actually works now, and if both CCW and CW turrets raise the erector up for UP elevation - I'm good.  Thumbs Up

 


Posted By: koshkin
Date Posted: June/19/2018 at 16:55
This comes from old Leupold target scopes (and some new ones) that had issues with the erector movement.  The problem also still persists in some newer scopes that are not designed for frequent turret twisting.

If you plan to spend a lot of time spinning turrets, get a scope that does it well.  Trying to deal with backlash in a modern world where there are many scopes that do not have backlash is a little silly.

For what it is worth, old Leupold target scopes had backlash going both ways: going away from the spring, and toward the spring.   

Leupold got away with it for many years because they did not have much competition.  That is not the case any more.

ILya


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Posted By: supertool73
Date Posted: June/19/2018 at 17:56
ACOGs seem to have this issue.  All 4 of the ones I have owned I have had to either tap with something or fire a shot to get them to settle.  Drives me nuts.  But where they are set and forget scopes, I deal with it. 


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Lifetime warranty and excellent customer service don't mean a thing when your gun fails during a zombie attack.

"A Liberal is a person who will give away everything they don't own."


Posted By: koshkin
Date Posted: June/19/2018 at 18:30
Originally posted by supertool73 supertool73 wrote:

ACOGs seem to have this issue.  All 4 of the ones I have owned I have had to either tap with something or fire a shot to get them to settle.  Drives me nuts.  But where they are set and forget scopes, I deal with it. 

They were never designed to be adjusted with any regularity.


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Posted By: RifleDude
Date Posted: June/20/2018 at 06:12
Originally posted by tpcollins tpcollins wrote:

Since I've learned how the erector tube actually works now, and if both CCW and CW turrets raise the erector up for UP elevation - I'm good.


It doesn’t matter the brand or price point of the scope. If the erector tube is being raised up, point of impact is being shifted DOWN and vice-versa. It doesn’t matter whether the turrets are CW or CCW rotation; that’s just an issue of whether they use a right hand or left hand thread. The erector (and with it the reticle) is always being shifted in the OPPOSITE direction of desired point of impact shift.

Just set your rifle in a rest and aim at a target. When you turn your elevation knob and you see the reticle moving upward on your target, that is in fact DOWN elevation correction. The same is true of your windage knob. If you turn the knob and see the reticle moving toward the left on your target, that is RIGHT windage correction. The reticle must always physically move in the opposite direction of your desired POI change. If you have a scope with unmarked knobs, once you do that exercise, you can then mark some kind of direction indicator accordingly. Just remember you should mark the indicator in the direction of POI shift, not erector movement direction, which is always the opposite.

To confirm what I’m telling you, repeat this exercise with scopes that are marked, and you will see this is always the case. The reticle must always be moved relative to the target image in the OPPOSITE direction of POI change. This is because when you move the reticle in any direction then use that shifted reticle as point of aim, you then shifted the position of the RIFLE (and with it, the barrel bore) in the opposite direction of change, moving your POI along with it.

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Ted


Money can't buy happiness... but it's much more comfortable to cry in a Porsche than on a bicycle.


Posted By: sambarman338
Date Posted: August/05/2018 at 01:46
Hate to agree with these guys Ouch, pt, but I would not worry about which way may be worse for backlash, either, unless you observe some tendency at the range.

For one thing, I've found the direction things move can be counter-intuitive. A German brand used to offer replaceable reticles, and the early ones I've seen were inverted. Later, once they started making constantly centred reticles, they came right way up.

If you have to take the knobs to the to edges of their adjustments, that is where you are likely to have most trouble, because the springs can be forced against the outer tube at difficult 'angles', where they may not move smoothly, causing the clicks to track badly. Various makers have endeavoured to eliminate this problem but the only example I can think of that cuts the Gordian knot is Swarovski's use of helical springs behind the erector tube, instead of beside it.


Posted By: sambarman338
Date Posted: August/05/2018 at 01:49
Sorry tp, I haven't found out how to edit these things once they are posted.


Posted By: RifleDude
Date Posted: August/05/2018 at 09:29
Sambar, the forum software settings are configured so that new members have to log 50 posts before post edit and photo upload functions are unlocked.


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Ted


Money can't buy happiness... but it's much more comfortable to cry in a Porsche than on a bicycle.


Posted By: sambarman338
Date Posted: August/05/2018 at 19:39
Thanks Ted, do other buttons come up once you've passed that point?


Posted By: RifleDude
Date Posted: August/06/2018 at 00:12
Originally posted by sambarman338 sambarman338 wrote:

Thanks Ted, do other buttons come up once you've passed that point?

I believe so. I don't remember what the "pre-50 post" menu looks like, so I don't know if the functions are missing from the menu or just disabled. I just know that you can't edit or post photos until you reach 50 posts. If you need help with a post prior to then, you're welcome to send me a PM.


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Ted


Money can't buy happiness... but it's much more comfortable to cry in a Porsche than on a bicycle.


Posted By: sambarman338
Date Posted: August/06/2018 at 00:51
Thanks Ted, I try to go over posts several times before sending but sometimes it's hard to refer back those of others, as happened with tp's initials. Also, no amount of proof reading ones own stuff ever seems to find everythingCry


Posted By: sambarman338
Date Posted: August/06/2018 at 00:53
... even just then I managed to leave out a to.Big smile


Posted By: SVT_Tactical
Date Posted: August/07/2018 at 08:49
 We also have a boost your post count thread in the Almost Anything Goes section you can use to get to 50 as well.

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"Most folks are about as happy as they make their minds up to be" - Abraham Lincoln


Posted By: sambarman338
Date Posted: August/07/2018 at 20:07
Thanks SVT, I'll just plod along. The number of posts made by some members here and at the main opposition are truly amazing. I'm not sure I'd want that many coals heaped on my head Ouch


Posted By: SVT_Tactical
Date Posted: August/08/2018 at 08:58

 Understand. 

 

Like Rifledude said you can always PM one of the Mods/Admins and we will get you to  email anything you want posted and we will post for you.



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"Most folks are about as happy as they make their minds up to be" - Abraham Lincoln



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