One shot zero

[Dr.Rob]

I've seen bore sighting = we'll make sure your scope points 'more or less' at the same place your barrel does.

For checking 'cold bore' zero. You could well use this method. But I'd pull the bolt, let the rifle cool off and replicate it 10 times before I was satisfied. Then I'd take it out of the vise and shoot it some more.

The worst time to sight in a rifle is the last month/week before the season opens.

On a side note I've seen that claim by Shepard for a 'one shot zero' and it never made sense to me UNLESS the rifle was bolted down.

 

[Sky]

Pistol Ranch there are a very select few rifles that will put bullets through the same hole at 100 yards maybe a few more at 25 meters. Define same hole? How many molecules are disturbed off the target hole. It can not be done scientifically speaking in that there will always be ( on a molecular level ) parts of the target hole removed even if your shot is dead center. Whose micrometer you want to use? Nit picking for the win!!!! Keep your money though and glad for the discussion. The success of what ever method you use is measured in targets hit or game brought in from the field; what is used by some might not be comfortable for others.

 

[BrocLuno]

I'm more likely to be one box than one shot. I like to see little holes in paper

 

[Picher]

I've used the method described, but only as a preliminary zero, when sighting in both my rifles and customers' rifles.

Shooting at least two more shots where I want them at that particular distance and under those atmospheric conditions, tells me that both rifle and sighting system are okay, and the shooter is doing things right!!!

Three shots in less than an inch is proof enough that the rifle, under those conditions, is hitting where I want it to, allowing for wind, etc.

If it were my rifle, I'd be sure to try the rifle and ammo under conditions close to what I expect to encounter during hunting season (or whenever/whatever).

JP

 

[jem375]

I've seen bore sighting = we'll make sure your scope points 'more or less' at the same place your barrel does.

For checking 'cold bore' zero. You could well use this method. But I'd pull the bolt, let the rifle cool off and replicate it 10 times before I was satisfied. Then I'd take it out of the vise and shoot it some more.

The worst time to sight in a rifle is the last month/week before the season opens.

On a side note I've seen that claim by Shepard for a 'one shot zero' and it never made sense to me UNLESS the rifle was bolted down.

Shepherd scopes work as advertised, I had one on a 7MM STW which I sold the rifle and scope later, didn't need the magnum and one on my AR15.
www.shepherdscopes.com

 

[AK103K]

Shepherd scopes work as advertised...

Yup, and they work well to boot.

 

[oneounceload]

PR - the issue I see is that most of my rifles need that first "cold bore" shot which will be somewhere other than where the rest of the rifle shots will be to get things settled in. If you do not know what type of grouping you have with that load, how can one shot possibly tell you? What if this load produces large MOA groups - do you know if you were in the N, S, E, W quadrant of the group? That could mean MANY inches difference, even at 100 let alone 300 yards - how much extra is 3 or 4 more shots really going to cost?

 

[Pistol Ranch]

I like to shoot as much as the next guy. I did this last season because I was the last shooter at my gun range before it closed and I was headed for my ranch.(The rifle was purchased at a gun show and all screws were checked at home)
I used the one shot zero rifle to kill a nice 10 point buck on opening day with one shot.
After the season, I took the rifle to the range and shot a M.O.A. group that was 1" high and 1/2" right at 100 yards with no scope adjustment.
I do not need any lectures on what I should have done (go earlier, etc., etc.)
Fact is, it works..The buck I shot was 144 yards (measured) from my blind.
I see a few shooters at the range that will show up with a new rifle and shoot a whole box of cartridges "zeroing in". In many cases, their targets look like they were done with a shotgun. It is extremely difficult to identify the "flyer" on those targets.

P.R.

 

[jmorris]

On a side note I've seen that claim by Shepard for a 'one shot zero' and it never made sense to me UNLESS the rifle was bolted down.

That is the beauty of how it works. You can take it off the bench, walk around, anything you want to do. You leave one reticle where it was and adjust the other to the bullet hole. In other words you don't loose your point of reference in the scope. If the rifle moves while you are adjusting you simply move it back to where it was using the POA reticle and continue to adjust the POI. Take a look at the photos I posted on the last page.

 

[AK103K]

Fact is, it works..The buck I shot was 144 yards (measured) from my blind.

Fact is, it might work, and just happened to work for you that time around.

Until you confirm you do in fact have a zero, you actually know nothing. If for whatever reason, your "zeroing" round was not consistent with what you normally shoot, you may well have no zero at all.

I see a few shooters at the range that will show up with a new rifle and shoot a whole box of cartridges "zeroing in". In many cases, their targets look like they were done with a shotgun. It is extremely difficult to identify the "flyer" on those targets.

Naw, not if youre paying attention. Its just chasing zero from a bore sighted gun to POA. When youre finished, theres no doubt where the zero is.

Not everyone has your faith, or skills at doing it your way. I can see where your way could get you close, but theres no way Id say the gun was sighted in using it, anymore than I would from bore sighting it. Any way you do it, you need to confirm your zero.

 

[Geno]

I learned the concept of a one-shot-zero from "John" (in about 1998). John was a very elderly gentleman who served in WWI. I can't recall what exact his expertise was, but was related to precision-shooting.

Interestingly enough, his preferred rifle at about age 90 was an iron-sighted, muzzle-loader. You all ever heard the expression crack-shot! Not a one of you here would want to wager your next check against (about) 90-year-old John. He'da handed all ya'll your backsides. John always, always used iron-sights. John's lessons were brilliant in their simplicity and effectiveness.

John used to hang-out at the Bald Mountain Range, and he would teach anyone who had the God-given good sense to close their yap, open their eyes, and open their ears. Holy Moses...that man taught me so much!!!

Here's the key...you have to have an accurate firearm to begin. Some here have criticized the technique, yet admitted that the firearm isn't sufficiently accurate. That's why you end up shooting groups. The better idea...sell the ineffective rifle. So, what's the real issue here...the one-shot-zero technique, or the faulty firearm that just don't shoot?! If your firearm (as do all of those that I have kept) will group between 0.50" to 0.75" at 100 yards, a one shot zero is fine.

As someone here said, Shepherd scopes--'nough said right 'here! The technique works. But you don't have to take my word, or John's word. The ammunition companies thrive on ammo sales to whose who hold tight to their pre-conceived notions...the doubters.

Geno

 

[Tim the student]

After the season, I took the rifle to the range and shot a M.O.A. group that was 1" high and 1/2" right at 100 yards with no scope adjustment.

I guess we just disagree on what "zeroed" means.

IMO, It may be close - but it ain't zeroed.

 

[MCMXI]

I'll zero my optics the way I've always done it. Bore sight at 25 yards and shoot two rounds. I'm typically within 6" of the POA at 100 yards after bore sighting. Adjust scope, shoot two more rounds, make fine adjustment and shoot two more rounds. Six rounds in all. Then I'll continue to adjust as I'm working up loads or practicing looking for that "perfect" no wind value zero.

 

[Geno]

1858:

That's about what I used do too. Since my 19-pound M700 Police groups in the 0.75" range at 300 yards, I'll fire 1 shot at 25 to 30 yards, 1 shot at 100 yards, and a final shot at 300 yards. That said, I am always on-target (a 15" steel plate) at 300 yards after a 1-shot zero at 30 yards. I take the extra measures to assure a flawless zero for varmint hunting.

But, I think the point the OP is trying to make is, that we don't need to fire 5-shot groups at 25 yards, then 50, then 100, then 150, then 200, then 250 then and finally a 5-shot group to our 300 yards zero. I would rather fire those rounds at 300 to 500 yards. FWIW, I used to do it the old way until John showed me the light. John saved me a lot of ammo that I shot into steel targets, instead of into groups.

When I was at the family farm yesterday, I fired a shot to get zero, then the next 300 rounds, all I heard was the ear-pleasing "TING" of steel ringing. Dear sweet Moses, I do love to shoot steel! Yeah, I was only shooting my Colt AR-15 with iron sights, my Marlin 981-T with a 4.5-14 scope, and my Marlin M60 with a 4X scope at 111 yards, but dang, I had fun.

Geno

 

[MCMXI]

But, I think the point the OP is trying to make is, that we don't need to fire 5-shot groups at 25 yards, then 50, then 100, then 150, then 200, then 250 then and finally a 5-shot group to our 300 yards zero.

I don't think you can put a number on how many rounds it does or should take to be confident in your rifle's zero. It'll depend on how important the next shot is, the size of the target, the range to the target and the conditions. For example, if you use this "one-shot" zero method, would you bet someone that you could hit a tennis ball at 200 yards with your next shot? Would you take that bet if the stake was $10,000? How about $5,000, $1,000, $500, $100, $50, $10, $5, or $1. How confident would you be?

 

[taliv]

if i'm just putting a known good scope back on a known good precision rifle, then yeah, i might zero in two shots. Bore sight, put one round on paper, measure how many mils POI was off from POA horizontally and vertically and make that correction on the knobs. fire the second shot. if it's dead center, then i would zero the knobs and call it good.

but if you're bringing something home from the gun show, it is entirely likely you don't know much more after the first shot than you did bore sighting it.

 

[Geno]

1858:

Well, I didn't serve in WWI, or any war, or even any military. But, I can say that John told me he could take 1 shot to assure his zero, and no more. His next shot had to hit the enemy. So, $$$ aside, the man literally "bet" his life on this skill that he was taught for WWI.

I wish the man were alive today to be able to chime-in on such threads...(and, frankly, so I could continue to pick-his-brain).

Geno

 

[Geno]

taliv:

You nailed it: it's situational: equipment & application.

Geno

 

[Norrick]

thats assuming your rifle is about 1 moa..


if you have a 5 inch group, you may just zero it to the edge of the group instead of the center. But yes, I do understand what you are describing.

 

[Leaky Waders]

I've heard of and used this method - it works.

But, I like to shoot alot of rounds just for fun, so once it's sited the rifle still gets warmed up some.

I really thought that this thread was about Shepard Scopes...I'm intersted in them for my newest rifle. But, I've never really looked through one.

 

[bracer]

Every firearm, site and shooter is a bit different. The one shot will only be on target at the distance or yards fired. Most of my big game rifles shoot about 2 1/2 inches high at 100 yards while the varmint rifles may be set up from 1/2 inch or more. So if the one shot would work for me at 100 yards the scope would have to be adjusted . I reload my ammo so I test fire them in five shot groups so the one shot site in is only a crude way to get started.

 

[dnthmn]

I had one Mauser that shot 6-8" groups at 50 yds. That would translate to 12-16" at 100 or 24-32" at 200. You'd have no way of knowing your rifle shot that poorly with 1 shot. You'd also have little chance of a clean kill beyond 50 yds. I made 2 trips to the range with it before getting rid of it, but what if that was with ammo it liked and it was worse with others??

 

[benEzra]

A one-shot zero will sight the scope somewhere within the rifle/ammo combination's cone of dispersion, however large that is. However, shooting a 10-shot group will allow you to see that pattern and sight in so the point of aim is centered within that cone. (And if you are concerned about cold-bore shots, shooting a series of 5 or 10 cold-bore shots at the same target will do the same thing.)

If your rifle's cone of dispersion is 0.5 MOA in diameter, then a one-shot zero will put you very close to perfect. If your rifle's cone of dispersion is 2 MOA, then the possibility for error is considerably greater. So it boils down to the precision of your rifle/ammo combination and how perfectly you need it sighted in, IMO.

 

[Justin]

Using a lead sled, sandbags or some other method to hold the rifle absolutely solid, fire one shot on the target.

So, in order to save a couple of bucks on ammo when I zero*, I have to drop a bunch of money on other ancillary equipment.


*Presuming there is any such thing as a one-shot zero.

 

[Dr T]

I have never used a bore sight that I would trust to get me on paper at 100 yards.

I do not live in a perfect world, and small changes to the scope may translate into big changes in point of impact if the muzzle of a rifle moves a very small amount. Remember that a minute of angle (MOA) is 1/60th of 1 degree. An inch at 100 yards translates into 0.005 inches at 18 inches.

I use something akin to this technique at 25 yards to make sure the rifle is on paper. Then I will use 3 shot (big game) or 5 shot (varmint) groups at 100 yards to fine tune the sighting. It usually only takes two or three groups at 100. The first to establish the 100 yard zero for scope adjustment, and the second and third (if necessary) to fine tune the zero. Plus, I get to shoot the rifle more.