Zero Stop Optic - Any reason to have it stop past 0?

[iodine]

I have an Athlon Eres BTR Gen 2 HD 4.5-27. It's a great scope. Anyway, I zeroed it in today (after swapping rifles) and set up my zero stop past 0, at about -7 which is -3 mils.

Does anyone else do this? I just felt like, and I'm not sure why, it would be handy to have it go negative "just in case".

Is this stupid?

 

[Huskydriver]

No but 3 whole mils below is probably excessive assuming you zeroed at 100

 

[Trigger Monkey]

It's fine, I set the zero stop under 0 on most of my scopes if they have a stop.

 

[salks]

There are occasions where you have an extreme cant say 45 degrees. Where it can be helpful. I don't know the exact math I tried it once and completely screwed it up but I know it's thing.

 

[hafejd30]

Many people do it for suppressed vs Unsuppressed zero changes

Or on rifles like mrad/DT or AI where you share the same optic on multiple barrel/bolt/caliber combos. Zero for the one you use the most then leave a bit of play under zero

 

[OREGUN]

Let’s just say you are refining your zero and your zero stop is set at 0….after a few groups you realize you need to come down a tenth. You can’t just do it and verify without getting out tools. That’s why I like to have a few mils under available. It weirds me out to slam down on the stop right at the zero of the turret.

 

[celltech]

If my zero stop allows it I go .5 mils to account for different loads. I tend to mark my hunting loads something like ".2 Down and .3 Right of zero".

 

[iodine]

Let’s just say you are refining your zero and your zero stop is set at 0….after a few groups you realize you need to come down a tenth. You can’t just do it and verify without getting out tools. That’s why I like to have a few mils under available. It weirds me out to slam down on the stop right at the zero of the turret.

this was kinda my thought process as well. It wasn't based on anything other than a hunch, however, but you put it into words nicely.

 

[iodine]

No but 3 whole mils below is probably excessive assuming you zeroed at 100

yep. i probably should've mentioned that it was a 100y zero, but it looks like i'm not too crazy (at least in this regard.)

thanks!

 

[longrange772]

If you play around with speed drop, dialing down is very helpful. Essentially your mil mark becomes your range.

 

[fxdwgkd]

I do on all of mine, usually about four to five clicks below. I always dial up to any range, not sure how or why I started this. So if going from 7.5 to 3.5 for example, I will dial down past 3.5 a few clicks and then back up to 3.5

 

[FuhQ]

My Vortex Strike Eagle 5-25x56 EBR-7C has the RevStop zero-stop system. It is setup out of the box to drop an extra 0.5 MILs below your set zero. I think that's kind of a cool feature, if you ever need to shoot something closer than 100 yards. I could see where that would be very handy for .22LR rifles. Personally, I zero all my guns at 100 yards...Even my .22LR rifles and .17 HMR's, lever-actions, etc...

 

[OREGUN]

if you ever need to shoot something closer than 100 yards.

. Say what?

 

[Rob01]

3 mils is excessive for a 100 yard zero. I like to have maybe .5 mils below my zero. With a centerfire rifle and 100 yard zero you don't need to go below your zero, even inside 100 yards, but I like just not slamming into the stop. I set all my scopes up like that if they don't come that way from the factory.

 

[iodine]

3 mils is excessive for a 100 yard zero. I like to have maybe .5 mils below my zero. With a centerfire rifle and 100 yard zero you don't need to go below your zero, even inside 100 yards, but I like just not slamming into the stop. I set all my scopes up like that if they don't come that way from the factory.

you're right. 3 mils is a bit excessive. I changed it to 1mil, should be a bit more realistic.

 

[Rob01]

Even 1 mil is a bit much but if it works for you then leave it. With a centerfire and 100 yard zero everything from 10 yards to 1000 is dialing up.

 

[NGCSUGrad09]

A few reasions you might want it:
- If you move the scope between guns, it's helpful to be able to tweak.
- If you have a multi-cal/prefit capable gun and have multiple barrels.
- If you have multiple loads you shoot through a rifle, some may have a POI change.
- The biggest elevation change I've seen and a reason for dialing under is if you have a suppressor and shoot with it on and off, you may have a POI shift that needs to be adjusted.
- Also, you need to dial under if you want to play with the Accuracy 1st Speed Drop stuff.

I usually set mine 2 Mils under zero and roll. It's not a big deal either way however you set it.

 

[iodine]

A few reasions you might want it:
- If you move the scope between guns, it's helpful to be able to tweak.
- If you have a multi-cal/prefit capable gun and have multiple barrels.
- If you have multiple loads you shoot through a rifle, some may have a POI change.
- The biggest elevation change I've seen and a reason for dialing under is if you have a suppressor and shoot with it on and off, you may have a POI shift that needs to be adjusted.
- Also, you need to dial under if you want to play with the Accuracy 1st Speed Drop stuff.

I usually set mine 2 Mils under zero and roll. It's not a big deal either way however you set it.

Thanks for confirming my hunch.

I do use different loads and don/doff my suppressor, so that makes sense.

You're the 2nd to mention 1st Speed Drop... not sure what that is so i'll google it.

Thanks!

 

[smoothy8500]

Yes, I set scopes to have .3 mill "under". Interestingly enough, Steiner T5x scope zero stops seem to have that feature built-in.

 

[ma smith]

common explanation is brake/supressor changes, zero shifts rifle to rifle, and angled shooting, etc
less common explanation is moving between mixed cant rails (eg 0 vs 20 moa)

 

[Trigger Monkey]

Thanks for confirming my hunch.

I do use different loads and don/doff my suppressor, so that makes sense.

You're the 2nd to mention 1st Speed Drop... not sure what that is so i'll google it.

Thanks!

Speed drop is a field expedient way to turn your mil reticle into a quasi-BDC so that the whole mil marks will equal the distance within a certain range of the trajectory. You do this by calculating a Speed Drop number that's taken from your dope, which is then applied to the turret by dialing under your zero by that amount. For example, the Speed Drop number for my SPR with 77's is 1.8, so when I dial under 1.8....2 mils, 3mils, 4 mils will equal 200, 300, and 400 yards respectively out to about 600 before it gets outside of it's accuracy tolerance, generally about 0.2 mils. I've confirmed this from 150 - 500 yards and it works pretty well. You can also use the Speed Drop number to calculate the dope using the range...for example 400 yards = 4.0, 4.0-1.8 = 2.2 mils of elevation.

Finding your Speed Drop Factor

Follow Sniper's Hide and pick up the latest information on all things precision rifle-related. Sniper's Hide Training is for the serious tactical marksman.

www.snipershide.com

Battle Ballistics For Easy Elevation Holds

Speed Drop is taught by a company named Accuracy 1st that is a method that provides fast, accurate elevation holds using a mil reticle.

www.gunsamerica.com

 

[Scttschnd]

I set my elevation zero stops below 100 yds in case during a load development test I need to go below if I am testing at 100 . I have found the need. Zero stop lets you go to bottom with out going a wheel or more in rev's and you lost the elevation. Had a buddy get lost in the dials at national Matches one year. we had to bore sight to find the dial setting to get him back in the center . He was so lost , insert head slap emoji here

 

[iodine]

Speed drop is a field expedient way to turn your mil reticle into a quasi-BDC so that the whole mil marks will equal the distance within a certain range of the trajectory. You do this by calculating a Speed Drop number that's taken from your dope, which is then applied to the turret by dialing under your zero by that amount. For example, the Speed Drop number for my SPR with 77's is 1.8, so when I dial under 1.8....2 mils, 3mils, 4 mils will equal 200, 300, and 400 yards respectively out to about 600 before it gets outside of it's accuracy tolerance, generally about 0.2 mils. I've confirmed this from 150 - 500 yards and it works pretty well. You can also use the Speed Drop number to calculate the dope using the range...for example 400 yards = 4.0, 4.0-1.8 = 2.2 mils of elevation.

Finding your Speed Drop Factor

Follow Sniper's Hide and pick up the latest information on all things precision rifle-related. Sniper's Hide Training is for the serious tactical marksman.

www.snipershide.com

Battle Ballistics For Easy Elevation Holds

Speed Drop is taught by a company named Accuracy 1st that is a method that provides fast, accurate elevation holds using a mil reticle.

www.gunsamerica.com

Very interesting... i'll look into this. Sounds great for on-target/speed competitions and whatnot.

 

[Trigger Monkey]

Very interesting... i'll look into this. Sounds great for on-target/speed competitions and whatnot.

It works pretty well with semi-autos and some bolt guns too depending on the application but it does have limitations just like a MPBR zero does too. Basically, another tool for the toolbox.

 

[Aftermath]

I set the zero stop so that I can dial one-half rotation of the turret under 0. I do this partly because I don't like making contact with the zero stop...sorta like I don't ever want to hit the stops at the bottom or top of the elevation turret.
I also use suppressors on most of my rifles and the zero changes on every single one of them. One of the rifles, using a suppressor, impacts almost exactly 1 MOA higher than without the can, another is close to 1.5 MOA higher with a can on. I have DOPE for each with and sans suppressor.
Granted, a half rotation is likely excessive and that's not what I am saying anyone else should do. At the same time, I'm going to continue to set mine up this way.

 

[redneckbmxer24]

If my zero stop allows it I seem to allow .5 mils to account for different loads. I tend to mark my hunting loads something like ".2 Down and .3 Right of zero".

This.

 

[brettb614]

My Steiner was preset at the factory to .3 Mil below zero. I set up most of my others that way as well (100 yard zero). Mainly in case environmentals/zero shift/etc require it. Don't think I've actually ever had to use it though.

One thing to keep in mind, if you are shooting ELR where you need all the dial you can get, you may need to consider minimizing how much you keep below zero, to free up space at the top of your elevation turret. If you don't, it's strictly what the shooter prefers as you'll likely never need all the vertical travel modern precision optics offer. Nice to know it's there though!