Number of shots to establish zero

[stats_guy]

Hey all, new member here. Looked for existing threads with similar topics but couldn't find any, and I'm curious.

How many rounds do you shoot at the paper to zero your rifle for a new ammo/load? 3, 5 and 10-round groups seem to be the popular rule-of-thumb numbers, but I'm interested to see if there's a favorite number that stands out.

Also, how often do you re-zero? Only when changing the load, any time the shooting environment is different (temperature, altitude, etc.), or some other factor?

 

[Old Man with Gun]

Zero is a relative thing. A match shooter / hunter should check zero before the match / hunt. Check zero often, if something changes or the next shot really matters.

To zero is something you do when it is not correct until it is correct. What is the goal? If your deer rifle is off by an inch at 100yds and you will shoot from a stand to no more than 40yds, who cares.

If I have a new scope to zero I start by shooting the dirt embankment. If the first shot is off by 3 feet I will adjust right away. No reason to waste ammo until on paper.

Once I'm within a few inches of center, it depends on the groups, there is no reason not to adjust if the first three rounds are tight.

But, if after ten rounds it is a shotgun pattern how do you know what to do? So for me it depends on how it shoots, the better it shoots, the smaller the number of shots to decide what to do next.

 

[Stuey]

I shoot 3 to 5 shots to zero. I should have that done by then. Anymore I feel like I have a fundamentals issue or a rifle issue. Also I zero before a match and after a match. Also I will zero after I clean it to validate I have not knocked anything off. I may be going overboard but I have instances where I have knocked something and rather not discover that in the middle of a match. That happened once in a major match.

 

[W54/XM-388]

If all was good with the equipment and all setup stable and such, I've zeroed using 3 rounds.

 

[DeathBeforeDismount]

The real answer: As many as it takes

You can zero with 2 rounds (one to see POI and the other after you adjusted turrets to POA) but generally once you are on target send 2 more to make sure POI/POA is the same. If there is a slight shift keep it in mind shooting. Often you will be a tenth or so off and its within the cone of fire of the gun/ammo/shooter. In fact that number is probably closer to 2 tenths for most shooters. Don't chase perfection. Get it within a tenth and you will be fine.

You zero every chance you get. If you have the opportunity to confirm zero before shooting at distance, do it. Many guys also check zero after shooting to make sure it hasn't changed as well as get a velocity reading to make sure it hasn't sped up or fallen off. A gun that tipped over and I didn't check zero may have cost me a spot at the finale this year due to scope shifting on my last stage. That's how important making sure you zero is correct is. If there is any doubt, go check it. Even if its just to relieve the mental stress of not knowing if its the zero causing issues.

 

[Old Man with Gun]

Let's not get into all the different zeros a rifle could have! Cold bore, clean vs fouled, different loads, altitudes, temperature, etc.

 

[OREGUN]

Before a match, at my home range, I will shoot at least a three shot group from 4 different positions and make necessary corrections to center all twelve shots around the POA. At the match, I might shoot 3x3 at 100. If the zero is good and the dope is true, at 300/600/900 as available. I’m done.

But that’s an excercise in making sure the average group center is as close as possible to POA from all different positions.

When a new barrel goes on or after a few fouling shots after a cleaning, I’ll shoot 3 rounds to make sure I’m still in the ballpark before resuming practice or training. I do a lot of practice on small dots at 100 though so I’m sort of always aware of what is happening with the zero and I usually don’t slip the turrets for less than .1 changes, day to day.

 

[SRPowah]

3-5 to get initial zero after a big change (new barrel, optic was removed, etc...). 1-2 to get on the dot, 2 more to verify. Somedays are rough and it takes me an extra 2 or 3. Any more is almost always an issue with my form or how the rifle is setup.

1-2 to verify zero prior to performing.

Keep a practical performance expectation or you will be chasing your tail. I don't care if my AI can typically shoot <0.6moa. If the groups are centered around the dot within 0.8moa, I am satisfied and move on.

 

[hlee]

How many to obtain a zero? As many as it takes. I like the theory of “shoot one, use reticle to measure correction, make correction on turrets, confirmation shot, flag and bag,” but it rarely works out that way for me.

How many ot confirm zero? Generally 1. If that one doesn’t hit the poa, we’re no longer in zero confirmation.

How often to confirm zero? Any time I’m going to need to make 1 shot count. Confirm; before a hunt, the morning of a match, after cleaning, after a fall or drop, after any maintenance, after any significant storage time.

 

[stats_guy]

Thanks all for the replies. Great points about how the number of shots to zero depends on how precise the rifle/load you're shooting is, and the intended application.

As you can probably tell from my username, I'm a bit of a math and stats nerd so I think about uncertainties associated with finite sample statistics a lot.

I've been working on an app (as a passion project that has consumed much of my last year haha) that does a bunch of statistical calculations with group and velocity data, and one of the outputs is the uncertainty in true zero based on the analyzed group. i.e. how far from the center of the group the actual population mean is likely to fall, at some confidence level. I figured the people here might find it interesting. To be clear, my intention is not to preach about sample sizes or what people should be doing, but to share what I think are interesting findings.

A "typical" .77 MOA 5-shot group has a 95% zero uncertainty radius of .54 MOA - i.e. the true zero is likely somewhere within .54 MOA of the group center. With a 10 shot, 0.83 MOA group (similar precision as the 5-shot group), the zero uncertainty radius shrinks down to 0.24 MOA. The white circle in the screenshot below represents the zero uncertainty region.

 

[Nik H]

If I have a new scope to zero I start by shooting the dirt embankment. If the first shot is off by 3 feet I will adjust right away. No reason to waste ammo until on paper.

This is what I do as well. In 2 shots, I move to paper and generally 3 shots later I am done.

 

[W54/XM-388]

If I have a new scope to zero I start by shooting the dirt embankment. If the first shot is off by 3 feet I will adjust right away. No reason to waste ammo until on paper.

This is what I do as well. In 2 shots, I move to paper and generally 3 shots later I am done.

In my case, at 100 yards, I usually make sure to have the rifle on a bench in a nice stand or well supported and then pull the bolt and look down the barrel at the target paper and try to get it lined up as best looks good, then adjust the scope to be looking at what the barrel looks to be looking like, check the view through the barrel again, verify exactly what spot on the grid the scope reticle is centered on, then put in the bolt carefully and fire the first round.


Most of the time, that gets it on paper, then proceed to go with moving scope reticle from previous position to bullet impact position.

 

[lash]

In my case, at 100 yards, I usually make sure to have the rifle on a bench in a nice stand or well supported and then pull the bolt and look down the barrel at the target paper and try to get it lined up as best looks good, then adjust the scope to be looking at what the barrel looks to be looking like, check the view through the barrel again, verify exactly what spot on the grid the scope reticle is centered on, then put in the bolt carefully and fire the first round.


Most of the time, that gets it on paper, then proceed to go with moving scope reticle from previous position to bullet impact position.

This is my most used method if at the bench. You should see the looks I get if I show someone how to do that with their AR. Because you have to break the action to pull the bolt and it looks weird but works just as well.

 

[carbonbased]

This is my most used method if at the bench. You should see the looks I get if I show someone how to do that with their AR. Because you have to break the action to pull the bolt and it looks weird but works just as well.

Sometimes I use the “dirt clod” method when first zeroing. Find a dirt clod or a small plant, whatever, near the target. Zoom out enough so you can reliably see the impact. Shoot and correct.

Once you’re close, move to paper.

It’s lazy and it’s hick. But hey, it works.

Usually this technique is employed when the 25 and 50yd ranges are full, so all I have is the 100yd.

 

[carbonbased]

But to answer the OP’s question, I guess I’m always checking zero at the range. Never know if a little bit of wind pushed your bullet or your technique on the previous outing day was off.

 

[NateVA]

Moving forward my zeros will be established with 20-30 rounds.

 

[scissorhands]

I get a zero every time I shoot for the day, and follow trends in my zero shift.

 

[stats_guy]

Moving forward my zeros will be established with 20-30 rounds.

Now this is big brain time

Joking aside though, I've started using 10 shot groups to zero for that extra bit of confidence. If you wanted to be really certain about your zero (maybe for ELR shooting), it may actually make sense to do 20 shots. For my application (mostly ringing steel to 600 yds), a ~0.2 MOA 95% confidence is more than enough.

 

[Jcarpenter223]

Usually 10-20 for me. 3 to get first group to indicate precision, dial in accuracy with the next 3, Confirm on a new target with the next 5, use the next rounds to confirm at 700 and 1k.

 

[diggler1833]

If I'm shooting an already proven rifle and load - 3 rounds.

If I'm shooting a brand new setup - I'll shoot one shot at ~40 yards to see where I'm at on paper, then the second shot will be at 100 and a rough zero established. Then I'm going to shoot several 5-shot groups to see how the load does anyway... so I won't zero until the last round. Call it an aggregate of at least (3x5).

If it is a hunting rifle, I'm going to check that zero and my drop chart at least a half-dozen times at various distances anyway before a season. I don't like hunting with a rifle either until I've shot it enough that I'm confident that the barrel isn't going to speed up anymore.

 

[JR1200W3]

I shoot two or three 5 round groups. One prone, one kneeling off a bench as if it's a barricade and maybe another positional.

I never never change my zero the morning of a match on the zero board. One three round group done that way is a notorious way to jack your zero up for a day of shooting for points.

The real answer is on any of my serious rifles, I am just confirming zero. Those two or three 5 round groups are going into a mental database of about 25 to 30 five round zero groups.

If you're using quality equipment you shouldn't see mechanical shifts in zero. You as a shooter is the biggest variable. It's really more about you being able to shoot your same zero in various locations, positions, and pieces of earth. In an overly philosophical way, you're zero'ing yourself to the guns mechanical zero.

A great exercise is a 10rd dot drills. Two rows of 5 dots on a sheet of paper aligned horizontally. At 100yds. Set your rifle down. Walk up the gun, lay down behind it, shoot one shot at the first dot. See where it landed. Review how the shot went in your head. Where was the reticle when the shot broke. How did shoulder, cheek, and bag pressure feel. Wobble zone. Head position, etc. Then get up, walk away, think about something else. Brain dump the last shot. Take a couple of minutes, then come back and repeat on the second dot. Do that for 10rds. Look at your POI on the 10-dot target. You can evolve that drill by using a pro-timer, but don't set a time as a goal. Just use the pro-timer to make a point of time and just mentally take not of your average times. You can further evolve that by shooting off a barricade, on a single dot. Single round repetitions on one POA. Build an aggregate of POI through individual executions on the clock. The goal is to inculcate the muscle memory and cognitive focus together so you can begin to execute good marksmanship fundamentals without having to think about it. Eventually you are freeing up cognitive processing power to begin to think forward in a stage and allowing subconscious, muscle memory to execute without deliberate focus.

Here's a 30 shot group for your thread. It was unnecessary.

 

[carbonbased]

In an overly philosophical way, you're zero'ing yourself to the guns mechanical zero.

I think this is a more elegant way to say what I was trying to get at.

 

[Ledzep]

This graph represents a rifle+ammo that is capable of ~1 MOA for 35-50 shots (truly a 1 MOA all day long rifle). Essentially a PRS rifle with decent factory ammo.

Along the bottom is how many shots are in the group. Along the side are the percent of groups (if you shot 1,000,000 rounds worth of that shot-size groups) that will create a group MPOI that is > 0.25 MOA away from the 1,000,000 shot MPOI (i.e. the true MPOI of the system).

 

[stats_guy]

Thanks Ledzep, that is a great chart and seems to match what I get with my simulated groups.

 

[Ledzep]

I've got a better one at work that has multiple dispersion capabilities on it. If I remember I'll post it up tomorrow.

edit: here it is. FWIW I do 20 shots for zero and avg. MV.

 

[TahoeDust]

Sometimes I use the “dirt clod” method when first zeroing. Find a dirt clod or a small plant, whatever, near the target. Zoom out enough so you can reliably see the impact. Shoot and correct.

Once you’re close, move to paper.

It’s lazy and it’s hick. But hey, it works.

Usually this technique is employed when the 25 and 50yd ranges are full, so all I have is the 100yd.

I'm lazy and don't like moving, so I started skipping the 50yrd rannge. Berm to get close then paper is my sop.

What do you guys call a good zero? 3-5 rounds within ~.5" from POA is usually where I call it good.

 

[mark5pt56]

Simplest way if you have a rifle to where you can remove the bolt/bolt carrier, etc. Rest it, look through the barrel to center an object as you do your best to treat the chamber, neck and barrel as "ghost rings" without moving anything, look through the scope and adjust to "see what the barrel sees" If possible, use the actual or close to zero distance to do this. A window ledge/corner works well as you can quarter it in the barrel view plus have a level and plumb to work with. With practice you can get very close, I'm usually within .2/.3 at 100. Saves ammunition and time.
Number of rounds? To be efficient, I will shoot one or two, makes adjustments, then 3-5 to confirm, normally recheck on another day. Sometimes on AR's I will add 10 rounds in there, especially with a dot to get a better sample-more of "what I see"

Now, zero check depends on what you are using the rifle for.
.22 short range matches-not a real concern as you get sighters but you should be close anyhow to start.
High Power as an example-you better have a good zero as you only get 2 sighters.
1000 yard match-I had a good zero and tried to shoot less than 5, usually 2-3 for confirmation then went for record as 20 minutes for 20 scored rounds, once you "went for record" no more sighters and some would get the barrel hot as fuck trying to get a zero. My 2-3 were still in, more of "ok, I'm good"
Hunting or work gun-you better know you varying range zero's and impact.

If starting with a fresh build or newly mounted scope, I record the scope settings and once zero is confirmed, reset zero/zero stop and confirm zero again-just I case something didn't go right monkeying with the dials.

As you all know, establish the zero then work those positions to note any changes-and to know your capabilities in that position.

My opinion, haha as every time these threads come up is the math squad comes in to say your sample size needs to be "x". Well true the more the better so to speak but then it gets into stupidity with time and resources spent to where one is mostly frustrated and tired and still haven't come to a conclusion. Once set, 2 consecutive 5 round groups is more than enough, confirm on the next outing and as needed thereafter.

To add-thin barrel hunting guns, keep it to 3 in my opinion, let the barrel cool and confirm. Depending on range space, distance hunting, etc. being able to confirm cb/ccb on numerous days leading up to season is great plus adding in positional with what you have available in the field whether its made made or natural object/props to shoot from.

 

[mark5pt56]

Everyone tracks data differently, book, apps, head, etc. One idea if is using paper is to have the same backer, makes marks to outline the target, use the same target and then after x times see what 10 cold/clean cold bores look like, what two separate 5 round groups look like, etc. Start with a clean backer and use that same spot for one gun. Note conditions etc. in the end you have 5, 10, etc. 5 round groups In that same spot. Yes, depending on the range, conditions will affect it, just another idea and approach to the madness.

 

[OREGUN]

I love a thread with a leading question followed, ten responses later, by a sales pitch.

 

[hunterx77]

If you understand moa it takes about 5 rounds.
1 moa equals 1 inch at 100 yards. Just shoot a group and see how many inches you need to go over and up, convert it to the correct distance and to your unit of adjustment.

As long as you shoot a tight group with all your shots you only really need 5 to 10 rounds.

 

[roostercogburn98]

As many as I feel necessary

 

[lash]

If you understand moa it takes about 5 rounds.
1 moa equals 1 inch at 100 yards. Just shoot a group and see how many inches you need to go over and up, convert it to the correct distance and to your unit of adjustment.

As long as you shoot a tight group with all your shots you only really need 5 to 10 rounds.

Uhm, you do not need to convert anything. Use your reticle as the ruler. Excepting if you’re using a simple duplex reticle perhaps.