Zero stop question

[RussellC]

Looking at scope specs, I see many that list whether or not they have zero stop. I thought I knew what this was, but I just looked a specs on a scope that did not have zero stop, but went on to list that turrets were "resettable to zero." Can someone explain this difference?

Another feature that baffles me in this regard are sets of spacers that are used to set zero stop on scopes that do not have zero stop.

Last question is a little more vague, I have a SWFA 14 x 42 scope. It has what looks like small Allen screws on the turret. I assumed that once you found your zero, say at 100 yards, you can loosen this, turn the knob to zero and retighten. Not touching it until I understand what I am doing.

Thanks for any clarity,

Russellc

 

[otisrush]

Do you have specific brand/model numbers for your first two questions?

My Nikon P-223 scope might be an example of your first scenario: After sighting in the scope the turrets can be pulled up (elevation turret) as well as out to the right (windage turret) and the dial moved *without* engaging the internal adjustment mechanism. In this way both turrets can be set to 0, however if one moves either turret more than one revolution (while really making scope adjustments - when the turrets are engaged) you have to keep track of that fact, because returning them to their 0 marking does *not* come with some sort of mechanical stop/resistance. So the turrets can be set to 0, but there is no zero stop. (This works great in how I use my .223 - as any scope adjustments I typically make for 100+ yd shooting don't require more than one full turn of the elevation turret.)

What does your owner's manual say about the turrets for your SWFA? I looked for a 14x42 model and couldn't find one.

 

[shoobe01]

Looking at scope specs, I see many that list whether or not they have zero stop. I thought I knew what this was, but I just looked a specs on a scope that did not have zero stop, but went on to list that turrets were "resettable to zero." Can someone explain this difference?

Zero stops are for "tactical" (exposed turret) scopes. They assume you have the gun set to only dial elevation in one direction, and prevents you from getting sign issues, speeds return to zero to allow counting clicks in the dark etc.

For example, my rifle is zeroed at 100 yds. The bullet rises to 100, then drops at all ranges beyond that. My dope chart has no signs on it, as I always just dial the only accessible number because the stop keeps me from going the other way. The turret is also labeled for this direction, so can go all the way around (mine and many: twice, which is another discussion entirely).

Another feature that baffles me in this regard are sets of spacers that are used to set zero stop on scopes that do not have zero stop.

Never heard of such a thing. Got a link?

Last question is a little more vague, I have a SWFA 14 x 42 scope. It has what looks like small Allen screws on the turret. I assumed that once you found your zero, say at 100 yards, you can loosen this, turn the knob to zero and retighten. Not touching it until I understand what I am doing.

Yes. BUT do not guess. Sometimes one screw is something else, and you should not just go loosening screws until you know. Find the manual for your specific scope.

When adjusting turrets, do it gently so you can feel for clicks. Once the turret is loose, it should not make clicks, but freely move. You turn the turret so the zero tick aligns by eye. Watch for parallax; no, not the parallax dial on the scope, but misalignment of your eye to the lines on the outside. Make sure the zero line aligns with the reference line /from the shooting position/, with your eye behind the scope, or you will be confused later.

Also, before loosening, watch how the turrets work. The turret is simply the head of a screw. It goes up and down as dialed. When the screws are loosened, you also can move the turret up and down. If you have it all the way down and then tighten the adjustment screws, you won't be able to move the turrret. If it is not a zero stop turret—or for the windage knob—if even nearly all the way down, it will limit how far you can turn it as it bumps into the turret base. Pull it up a bit to give room and play with it once adjusted. You may have to do it a few times to get proper distance to turn both ways enough.

 

[Varminterror]

Resettable turrets = can be reset so your rifle shows zero at your desired range. Typically the knob is mounted on a toothed assembly, such it can be removed after the rifle is sighted in, and then replaced to show zero.

Zero stop = the turret knob cannot be turned down past your locked zero range. This is often a set of shims which set under the turret knob, such it bottoms out when at your set zero. This is a really nice feature if you’ll ever be dialing more than a full turn. It’s a pain when you realize your knob is showing zero, but you're really dialed 12mils because you’re one rev off from your zero.

So say you bought a new rifle and scope, you install the scope, take it out and shoot to sight it in. The turret reads randomly 1 rev + 4.7mils when you are hitting POI = POA at 100yrds. You remove the turret and reinstall it to show 1 rev + 0.0 Mils: this was the resettable zero feature, so the scope is now zeroed to 100yrds for your load. You shoot again to confirm the zero, and it’s dead on, so you grab the shim set and slip them under the knob until it offers a hard bottom at 1 rev + 0.0 Mils: this is setting the zero stop. Now you dial for 1760yrds, spinning the turret like a felon, two full revs plus 2.3mils (scope shows 3 rev + 2.3mil). You forget to dial off, drive home, throw it in the safe for a month, then come back out, forgetting the range you last fired, you dial off 2.3mils to hit 0.0, and wonder why you’re hitting 7” high at 100yrds. You turn the knob a couple clicks negative below zero and realize you’re not against your zero stop... you turn off the 2 revs, hit the zero stop, remember - oh yeah, last time I shot this was at a mile! - and you have yourself back on zero at 100.

 

[Varminterror]

The turret is simply the head of a screw.

I can’t recall any scope model for which this is true. The knob itself is a keyed indexing knob which mates to the elevator or windage shaft. The knob is then sandwiched in place by a screw. Even for slip reset turrets, the knob is not threaded, it is only keyed to the shaft.

 

[RussellC]

Ok, that clears a few things up. The SWFA didnt come with a manual, there is on line info, and a number to call. I dont think, but will check again that its knob can be just lifted and turned and set back down. Im pretty sure that is what had me looking at those screws. A call to SWFA may be in order. Wish I had of had the smarts to get the Mil version instead of the MOA version of reticle, but what's done is done.

Not touching screws until I am sure what is what.

Russellc

 

[RussellC]

It also sank in about the shims, if I reset the knob to zero, that's fine, but there is more adjustment "left over" which becomes a problem when you adjust for another longer distance, and then return to "zero." The shims take up that left over adjustment like a proper zero stop would.

I have a feeling these shims will be required for my fixed power SWFA scope.

Do I have this right, or still off base a little?
Need to call SWFA, and possibly obtain a set of shims.

Russellc

 

[RussellC]

Jackpot....there is a ton of YouTube's on my scope and use of these shims.

Russellc

 

[Varminterror]

Sounds like you’re in the hunt now.

 

[RussellC]

Zero stops are for "tactical" (exposed turret) scopes. They assume you have the gun set to only dial elevation in one direction, and prevents you from getting sign issues, speeds return to zero to allow counting clicks in the dark etc.

For example, my rifle is zeroed at 100 yds. The bullet rises to 100, then drops at all ranges beyond that. My dope chart has no signs on it, as I always just dial the only accessible number because the stop keeps me from going the other way. The turret is also labeled for this direction, so can go all the way around (mine and many: twice, which is another discussion entirely).



Never heard of such a thing. Got a link?




Yes. BUT do not guess. Sometimes one screw is something else, and you should not just go loosening screws until you know. Find the manual for your specific scope.

When adjusting turrets, do it gently so you can feel for clicks. Once the turret is loose, it should not make clicks, but freely move. You turn the turret so the zero tick aligns by eye. Watch for parallax; no, not the parallax dial on the scope, but misalignment of your eye to the lines on the outside. Make sure the zero line aligns with the reference line /from the shooting position/, with your eye behind the scope, or you will be confused later.

Also, before loosening, watch how the turrets work. The turret is simply the head of a screw. It goes up and down as dialed. When the screws are loosened, you also can move the turret up and down. If you have it all the way down and then tighten the adjustment screws, you won't be able to move the turrret. If it is not a zero stop turret—or for the windage knob—if even nearly all the way down, it will limit how far you can turn it as it bumps into the turret base. Pull it up a bit to give room and play with it once adjusted. You may have to do it a few times to get proper distance to turn both ways enough.

I don't have a link, sounds like it is a member on snipers hide. Several of the you tubes use them, and give name. Sounds like they are around 22 bucks shipped, at time of youtube anyway, are made of Delton.

Russellc

 

[RussellC]

There, question answered, shims on the way, this place is the greatest.

Thanks all,

Russellc

 

[RussellC]

Do you have specific brand/model numbers for your first two questions?

My Nikon P-223 scope might be an example of your first scenario: After sighting in the scope the turrets can be pulled up (elevation turret) as well as out to the right (windage turret) and the dial moved *without* engaging the internal adjustment mechanism. In this way both turrets can be set to 0, however if one moves either turret more than one revolution (while really making scope adjustments - when the turrets are engaged) you have to keep track of that fact, because returning them to their 0 marking does *not* come with some sort of mechanical stop/resistance. So the turrets can be set to 0, but there is no zero stop. (This works great in how I use my .223 - as any scope adjustments I typically make for 100+ yd shooting don't require more than one full turn of the elevation turret.)

What does your owner's manual say about the turrets for your SWFA? I looked for a 14x42 model and couldn't find one.

You are right. It is either 12 or 16x.....there is no 14x listed. Not at home right now, I new it was larger than 10x, but I didnt go to the 20x. I will have to look at it.
They all work the same in this series.

Russellc