Here is how I sight my gun in. I use a ballistic calculator to find how high I must be at 100yds to be dead on at 200. I then shoot for groups at this height at 100yds. Next, I shoot at 200yds and 'tweek' from there to be dead on. Next, it's back to 100 to record where it shoots. All my guns are about 3-4" low at 250yds, 7-9" low at 300yds, 12-15" low at 350yds and around 2 feet low at 400yds. Heck, I'm not sure that I can know what a few inches is in my scope at those distances. When I hunt I use a range finder. BTW, my longest shot to date is around 300yds. capt david

I sight mine in so they are dead on at 275-300 yards, depending on the caliber. I sight-in at 100 yards--putting it high according to the charts. I then go to 300 yards and check it.

My longest shot was 490 yards for a muley.....

I follow a similar path myself. Then just before the season opens I clean all my nice rifles, put 'em in the locker and grab either a Mod 94 Trapper or the T/C Carbine and go still hunting. Their zero has never changed in the years I've owned them. 26 for the Trapper, 8 for the T/C. Then I go shoot a deer at 10 to 30 yards distance. That's the thing I hate about still hunting, you never get to take long shots. Don't need a scope either. Can't justify one of those Wiz Bang magnumbs either. One of these days...

I sight in alittle high at 100 (1-2") and then zero at 200 some of the Mags are only .75-1" high at 100 once zeroed at 200 contrary to what my charts say. I have one rifle (7 Wea.) zeroed at 250.

Brush guns get zeroed at 100.

Reloader

I start at 100 yds., with a sight-in POI that is where the book says it should be for the actual velocity of the load I'm using, as measured by my Oehler 33 chronograph. Charts and graphs that are supposed to tell you what your load is clocking amount to little more than outhouse paper most of the time. EVERY rifle is a law unto itself, and it doesn't pay to trust anything but a chronograph and actual shooting as you develope your final zero.

Then I shoot at 200 and 300 yds. to confirm and make adjustments. There are nearly ALWAYS adjustments to be made at 200 yds or 300 yds. The '2" high at 100' concept is another urban myth that can lull you into a false sense of security.

Mechanical shooting rests offer more deceptions, as does the hand-off-the-forend/squeeze-the-rear-bag, benchrest-style shooting position. You CANNOT achieve a final, workable, actual, honest field zero off a mechanical rest from a bench. You can achieve some pretty groups alright, but not a final zero. The only way to come up with a true field zero is to shoot the rifle as you would in the field -- with your hand grasping the forend, and the forend NOT in contact with a stiff, mechanical sandbag rest, which only imposes artificial conditions on the rifle.

Champion high-power rifleman David Tubb, in the 'American Rifleman', is the ONLY true, real-world authority who has gone into correct detail on this topic, and he's the only man I know of who has actually addressed this entire issue in print.

Lot's of guys experience "mystery misses" in the field, and a GREAT many of these unfathomable misses occur because of false, assumed zeros that were "finalized" at the bench back at the home range. If you're a benchrest shooter, that's one thing, but with a HUNTING rifle, it always pays to confirm your zero by getting OFF the bench.

BIPOD zeros can vary greatly as well, rifle to rifle.........

AD

I'm with you, Dan....

I used to sit in stands or at the base of a tree, waiting on game to come to me.. For the last 10-20 years I've been more active.. I really like to get in the woods and slip around... I find it an enjoyable way to hunt. And I see and take my share of game.

For this style of hunting I don't find it necessary to sight in 3" high @ 100. In fact, such a sight in can cause high shots on game at the intermediate distances. I normally sight in 1 to 1 1/2" high at 100. I can kill anything to 300+ but 99% of my shooting is WAY under that.
Works for me..

In the past two years, I have read many excellent posts by Allen on rifle issues. This post on sighting in a hunting rifle is the single best advice on that critical point that I have ever read and I do exactly this with my rifles....but, I still sometimes miss!

I cannot urge anyone just getting into hunting rifles to do exactly what Allen is saying, this is especially crucial with rifles of heavy recoil.

I zero so that my bullet is never more than 3 inches high at any range. I have never understood why anyone would zero so that their bullet is 4 or 5 inches high. Zero at 300? How high are you at 180 yards? At least 4 inches, I would bet, which means you must shoot 2 inch groups in the field or you risk a miss. "Hold low" you say? Why? Why not zero between 200 and 250?

Game at 150 to 200 yards often knows you are there. You often don't have a lot of time, and often you must shoot standing.

AD: I will take issue with Tubb for saying that one should zero so that their trajectory is a maximum of 5 inches high. But if anyone can shoot one hole groups, it is him. Five inches high for most people is a miss.

But I do zero from field positions. I always zero sitting, either with a bipod or not, but always with a sling. I have not found my zero to be significantly impacted by a bipod, and if it is, it is never more than 3 clicks at 600 yards - I haven't had this problem on game.

I have found the zero to be greatly impacted on rifles with a sling stud on the barrel. There is a reason black guns have the stud on the sleeve (unlike the issued rifles).

I bench shoot all of my rifles and sight them in according to where I'll be taking that particular rifle.

I bench shoot to 400 yards. Then I use every conceivable shooting position out to that distance. It is not uncommon for my brother to drive up from SC before we go on a hunt and we'll spend about a week at the range. (To anyone feeling like a wisea$$, that means going daily for hours at a time for up to 7 days ), and not spending the night there.

We like to see what the rifles are doing out to 400 for sure before we head to WY or CO or UT. But we practice with our bipods, prone, kneeling, Indian style, upright on a shooting post or up against a tree. And yes, sometimes it is quite humorous when we do not get a good shot off because our eyes begin to fatigue or we lose our concentration, but the same thing occurs when shooting at bow camps during the offseason. That is when we know it is time to break.

I have noticed one thing over the years, when we do shoot with our hand supporting the rifle instead of the sandbags, we tend to hit about 2" higher between 300-400 yards.

I have all of Tubbs material too. Good stuff.

I like my 300 RUM to be dead on at 400. If anything is closer, I just aim in the bottom third of the zone and squeeze. It's worked so far.

I sight in for a CONSERVATIVE max. point blank range for the smallest species i'm after, then i apply a MPBR rangefinding system (depending on the reticle style i'm using) for the largest species i'm after.

While I have been checking zeros with rifles longer than most here have been around its really not as hard as it's made out and I mean small varmints! Big game is easy as compared to a chuck!

I have carried my drop data with me since I manually calculated it long before there were computers. The big challange for me has always been the wind. The drop is quite easy out to over 300 yds and that's pretty far to shoot.

Most of my rifles are zero'd at 200yds except for the muzzleloader and the 358's. The Swift and 264 are one inch high at 200 yds.

Allen Day has the facts, no doubt about it. Soon as I move to Wyoming I'm gonna be using that approach without doubt. Till I find the need for long range varification of sight in though, TLAR(That Looks About Right) at 200 yards will do. Oh, and a double No Joke on holding your rifle for zero. Even at distances of 100 yards it can have a profound effect. Sad fact down here in the South, there aren't a lot of ranges that have more than 100 yard lines. Fewer still that have more than 200 yd lines, and so on and so forth. A point of jealousy I live with when you fellas from out west chime in.

Sorry guys, I'm going to have to disagree w/ the Zero Shift Hypothesis.

I've always sighted my rifles in on either old shot bags filled w/ sand or popcorn or leather sand bags while sitting at the bench, my zeros have always been the same when shooting w/ hands on or off the forearm, shooting Benchrest style (Hand on the rear rabbit ear bag), shooting off sticks, etc., etc.

When you are dealing w/ a rifle that has a floated bbl and a sturdy stock, it does not matter what the forearm rest against whether it be your hand, a sand bag, bipod, block of wood, shooting rail, etc., etc.

I think it is your shooting style that skews these zeros that some experience. It most likely has to do w/ your trigger squeeze technique and a very slight flinch that you are not aware of while shooting in different positions.

I'm not saying what you are saying is not true, you may indeed shoot to a different zero from different positions but, It's not the gun that is doing something different it is the shooter. Even if you do shoot slighty different, say an inch or so at 200 yards, that's not going to hurt you while afield on reasonable shot distances.

Good Luck!

Reloader

Reloader

I have seen many sporting weight rifles that will change zero when hand held versus just laying over the bags . Usually with rifles that have substantial recoil.

For instance , my 7mm mag will shoot 2.5 inches higher at 100 yards when just layed over the bags , versus a normal hand hold on the forend.

I zero using a ruck sack (steady field position) at 150yards. Totaly agree that hunting rifles need to be zeroed in the conditions they will be used in.

AZ, I agree with you that 5" above POI at any range is simply too much rise, and will likely cause a miss, especially under hunting conditions shooting up or down hill.

With the 300 Win. Mag. and 180s @ 3100, I sight-in at 250 yds., which puts the bullet + 2.5" at 100, + 2" @ 200, and - 3" at 300. I prefer a 250 yd. zero over a 300 yd. zero with this cartridge, and this reduces mid-range misses considerably.

I normally sight-in the 338 Win. Mag. for a 200 yd. zero (+ 2" @ 100) with 250s, but I re-sighted my rifle recently with 225 gr. Nosler Accu Bonds for possible open-country elk use this season. I get 2850 fps. out of my 225 AB load, and with a BC of .550, it's entirely practical to sight-in for a 250 yd. zero. This puts the bullet 3" high at 100, and not quite 4" low at 300. Flat enough near and far for elk use........

AD

This is a VERY IMPORTANT TOPIC! I've found that missed game is more often due to shooter error than gun/cartridge performance. Yet, we spend more time on this forum discussing nerdy details (gadgetry) that usually have little to do with hunter success.

I sight my high-powered rifles in for a 300 yd. zero. This means somewhere between 2.5 and 3.0 inches high at 100 yds. (2.5" for the mags and 3.0" for the '06-like cartridges). Thus, at 400 yds. the POI is ~8-10" low, at 500 yds. 20-25" low, and at 600 yds. 40-45" low. I don't shoot beyond 600 yds. It is important that with this 300 yd sight-in the gun will be shooting ~4" high at 175 yds, and this can cause high misses, especially if you over estimate range. Thus, I advocate using a range finder, when you have time. Often you do have time, and laser ranging the game animal will help "settle" you down by making the shot a calculated or planned event - buck fever affects most folks. Indeed, it's the rush I'm looking for.

I like the new Leupold Boone&Crocket reticle, which is graded, and easy to use for long-distance shooting.

Now, once the gun is sighted in, you must be ready to shoot with a STEADY AIM in the field. Hence, I use the Harris bipod, which is a great investment. I get the 27" model, because I like to shoot from the setting position - a position one can assume quickly. I've found the POI to be essentially identical between bench rest and the bipod. Personally, with a first-rate gun and shooter, the gun will shoot where you point it, once it's sighted in. If there's a difference, you're flinching, and we tend to flinch the same way with each shot. Often you're not aware you're flinching, which is usually unconscious. The bipod not only makes you steady, but also it dampens flinching and forces you the think-through the shot, hence countering the nerves of buck fever.

Also, in the field there are many variables that are hard to plan for, but must be included in your shooting, especially if you're shooting at long ranges. For example, are you shooting up or down hill, what is the elevation, and is there significant cross wind. The latter is a pain-in-the-ass and difficult to estimate and correct for, especial during the frenzy of the actual shot. You can only do your best.

I'll initially sight at 25 yards. Boresight by looking through the bore, then one shot. With the rifle carefully bedded to POA, I adjust the reticle to line up with POI.

Then back to 100 yards, one shot, same procedure.

Then back to 200 yards, three shot group. At this point, I mark the bullet holes with flourescent marker so that I can see them through the scope, and again bed the rifle carefully to POA and adjust the reticles to the mathematical center of the group.

I'll usually fire another three shot group from the bench for verificaion, and then it's time to practice practice practice from field positions. Occasionally I'll have to make big adjustments from benchrest to field positions, but not usually.

So the gun is zeroed at 200 yards, which usually puts it around 2" high at 100. My personal "comfortable" maximum game shot is around 200 yards, with 250 stretching it a bit. On an 8" target at 300 yards from a looped-up field position, my average first-round hit probability is about 90%, which in my opinion is unacceptable, so I won't shoot at an unwounded game animal at that distance. I am far more proud of shooting a game animal at 35 yards than I am of hitting at 350, so have no use for zeroing at 250, 300, or further. YMMV, but I am inclined to call for jail time for anyone who wounds a game animal five or six hundred yards away.

How about when your in camp, or in the field and need to check zero.

I have learned from past trips, that when I arrive at the area to be hunted, there is NOT always a 100 yard range to check zero.

You know, "Lets see how good you can shoot, hit that paper plate out there. "'It's about 100 yards, ain't it?"

What I have discovered that works well is to fire three groups at your home range after final sighting in. One at 25 yds, one at 50 yds, and another at 100 yds; all on separate paper targets. Take these targets with you, and when you arrive and find out you only have 50 yds at camp to check zero, put up that 50 yd paper target you brought with you. Fire a few shots. If they are inside the group you fired at your home range, you are good to go.

quote:

When you are dealing w/ a rifle that has a floated bbl and a sturdy stock, it does not matter what the forearm rest against whether it be your hand, a sand bag, bipod, block of wood, shooting rail, etc., etc.

Not to belabor the point, but it does matter, floated barrel or not. The difference may be slight or significant and in the case of the former very difficult to ascertain when switching to field positions. The effect in not caused by bedded barrels nor eliminated by floating them. The issue is how the rifle recoil impulse interacts with your body, something that differs from bench position to field position. Recoil starts before the bullet leaves the muzzle.

I have to go with reloader on that one. A floated barrel in a stiff stock shouldn't change point of impact because you have your hand under the forend instead of rest. Your position and trigger control under different field positions might make the shooter shoot at a different point of impact but the rifle should still shoot be shooting the same.

AnotherAZWriter, I want one of those rifles that's 3" high at all ranges!

I shoot iron sights nowadays; sort of my compromise 'cause I don't want a bow. When I see a deer at 300 yds I get up and run like hell straight at it. Re-defines "deer in the headlight stare" but I'm so old and fat I can't hold the gun still when I get there. Good exercise for me and safe for the deer; a win-win if ever there was one.

Of course, when hunting seaon opens all bets are off....

I'll guarantee you that not every rifle shoots to POA off of a bi-pod. Some do, but some don't. There are no universal truths about bi-pods, but I do recommend that anyone follow Harris' instructions for proper use and shooting technique.

I had a Penrod-built 270 Win. that would absolutely maintain a perfect zero from either standard field positions or off a bi-pod.

I owned a David Miller 300 Win. Mag. that would shoot 3" to the right at 100 every time from a bi-pod, while my current Echols-built 300 Win. shoots close enough to POA not to matter......

AD

I haven't tried it with every rifle I own but two that I did try definitly shifted POI when the rifle was fired of the bags and when off the bags but with my hand between the forearm and the bag and the butt unsuported. One rifle, off the bags, shot maybe an inch and a half high at 100 the other I don't recall at 100 but it was four inches higher at 200. These results were repeatable.

Now every rifle I sight in I do it off the bags but fire a final group or two holding the forearm with my hand resting on the bag with the butt unsuported to make final adjustments and double check.

If I shoot off sticks the POI tends to be higher just resting the forearm on the y than when I put my hand on the y and hold the forearm.

JPK

Hello the campfire:
What I get out of all this is that:
1. You should sight yur rifle in at least each year because the zero might have changed due to being knocked around, differant ammo, ect.
2. There are several good ways to sight in and not every one of them is good for everybody else. You need to do whatever you have confidence in.
3. The point is to know where your bullet is going to hit.
4. Each gun and load is different.
5. Practice helps.
6. Everyone should sight his own Rifle because soneone else's zero might not be yours.
7. The first shot counts
8. a hot barrel and a cold barrel might shoot differently. A clean barrel may shoot differently than a dirty one. Know how yours shoots each way.
9. It is hard to judge distance over 100 yards without a range finder.
10. If you are going to hunt with a rifle, know how it shoots under the conditions you hunt in.
11. It does not contribute to the accuracy of a rifle to throw it in the back of the ruck and bounce it around, nor does it help to put it under the other gear, let the kids sit on it, drop it in the dirt or sand, or have the sling breakand drop it.
12. Learn how to shoot with a sling because you will shoot better. Not all slings are for shoting. Check your slings and swivels because they break.
13 Carry a sighted in back up.
14. Hope for the best, plan for the worst.
This is just my two cents.
Judge Sharpe

For my woods rifles where a 200 yards is a very long shot I sight them in about a inch high at 100.

For my longer range rifles I have went to all multi reticle scopes and sight them in to match the reticles.

I find multi reticles make it a brezze to hit at longer ranges. These and a good laser range finder make hits out pass 300 yards almost to easy. Mil dots or balistic plex for me please.

This business about the POI changing drastically from the bench rest to the bipod or traditional sitting or prone shooting positions is vastly over rated. I'm a benchrest rifle shooter, and we worry about consistent recoil to get the last 10th of an inch out of the 5 shot 100 yds group, but POI changes measured in inches is rediculous. If that's happening to you, you're flinching big time!

I sight in 1.5" at 100 yards and shoot like hell at all distances,and use a range finder when I can.I try to keep my shots under 400 yards and instictively hold over from that point. I also load all my rifles with loads that generate nearly the same trajectory.
You can call some good shots if you know
where you rifle shoots and how far the target is!No fancy recticles either.
Just gotta shoot more

I use a chronograph and its external ballistic program to determine sight height. Then I print out the bullet path to 500 yards(which is max for my program), in 50 yard increments, lay it on the buttstock and overlay with clear packing tape. Laser rangefinder gives accurate ranging and a quick glance at the chart gives aim point. I did this for both rifles I took to Namibia where 300 yard shots were common and far greater than I ever experienced before.

As others have already said, practice from likely field positions while at the range. For me it was off shooting sticks.

quote:

quote:
When you are dealing w/ a rifle that has a floated bbl and a sturdy stock, it does not matter what the forearm rest against whether it be your hand, a sand bag, bipod, block of wood, shooting rail, etc., etc.



Not to belabor the point, but it does matter, floated barrel or not. The difference may be slight or significant and in the case of the former very difficult to ascertain when switching to field positions. The effect in not caused by bedded barrels nor eliminated by floating them. The issue is how the rifle recoil impulse interacts with your body, something that differs from bench position to field position. Recoil starts before the bullet leaves the muzzle.

Dan,

I'll reiterate my point, The "Change of Impact" is NOT in the gun itself, it's in the shooter. That is considering the rifle has a rigid stock and floated bbl. Recoil has nothing to do w/ it as long as your trigger squeeze and shooting techniques are the same. Recoil doesn't mentally transfer to the shooter until after the projectile has exited the bbl. As far as recoil effecting you by your position, most all positions I shoot in involve the same basic shoulder position as used while at the bench unless, I'm in the prone position.


Again, I don't disagree that some of you shoot different w/ certain rifle from certain positions but, a well built rifle is going to shoot the same regardless of the position as long as the bbl, stock, and action are not under any stress.

Good Luck!

Reloader

quote:

Originally posted by p dog shooter:
Mil dots or balistic plex for me please.

I'm with p dog shooter on this one, with the exception that my "woods" rifle is also my "long range" rifle.

I hunt the mountains of NW Arkansas and although most shots (woods, food plots, small fields) are 150 Yds or less, there are opportunites on clear-cuts, high-lines, bigger fields, etc. for 200-350+ Yd shots.

I sight in dead on at 100YDs with a 3-9x40 Burris Ballistic Plex. Most of my hunting is still hunting or setting up in woods, small fields, food plots, where I keep the scope on 3X. With a 100Yd sight in I'm only 1" low at 150Yds. But when I do set up on the open / long range areas I can crank the scope up to 9X and use the B-Plex features for 200, 300+ yard shots.

Sighted in dead on at 100Yds with 140Grn Accubonds, I'm 1/2" low a 200 Yds using the 200 Yds hash mark in the reticle. Our range only goes out to 200Yds so I haven't had a chance to check actual 300 Yd & greater impact points, but my ballistics software inticates I should be within an inch all the way out to 500Yds using the appropriate hash mark. (Not that I would take shots out that far!)

To me, it's the flexibility offered by these "multi reticle" scopes that is important. At my normal hunting ranges I can really "thread the needle" if I need to as opposed to haveing to compensate for being sighted in 2" or 3" high. At the longer ranges, I don't have to guess at, look at a chart, or remember the amount of needed holdover. I just use the appropriate hash mark on the reticle.

firstshot
----------------------------
Make your first shot count!

I used to zero my 7mm Rem Mags at 300 and then noticed they hit 4 inches high at 180-200 yards - enough to miss.

It seems the most experienced hunters use a 200-250 yard zero. 300 would be great if the bullet didn't rise too high, but unfortunately, they do.

Regarding the impact change, I remember I had to click for windage (and obviously elevation) when I shot sitting when I shot competitvely due to the stress of the sling pulling on the barrel (it was a really tight sling and a standard issue black gun).

Ackley Improved User, Reloader,

If its repeatable its not flinch and its repeatable. The group size remains essentially the same but the POI moves.

Neither barrel of the two rifles I purposefully checked for this is free floated but neither stock, both english walnut, is in the light weight class either. I think it happens with most if not all rifles to one degree or another, at least hunting weight rifles, and the bigger and harder recoiling rifles the most.

I think it has to do with the way rifles recoil off very firm bags vs the way rifles recoil when there in your hand and your pulling the foreend down and back.

JPK

First Shot,

That Ballistic Plex is nice, I've only been able to shoot out to 400 w/ the one on my 25-06 but, it was w/in 3" of dead center, plenty close enough for a good shot on a deer. If you'll taylor your loads for the hash marks, it is a great piece of equipment.

I'd love to get back out West and try it out on Antelope.

Have a Good One.

Reloader

quote:

Originally posted by allen day:
Champion high-power rifleman David Tubb, in the 'American Rifleman', is the ONLY true, real-world authority who has gone into correct detail on this topic, and he's the only man I know of who has actually addressed this entire issue in print.
AD

Alan, you always have good stuff.
What month was this? I must have missed it.
(another sure sign of AGE creeping up...)

Wayne VanZwoll has a good article in a recent (last 3 months?) American Hunter or NAHC about the same thing. He also advocates sighting in by shooting just like you do in the field (something I learned awhile back), the diffferences in prone or standing, why sighting in somebody elses rifle causes misses, shooting with a tight sling, etc.

I will go back through my back issues of AR and look for the Tubb article.
Now where did I put my glasses...

Reloader

Within 3" at 400Yds will definitely "Get er done"!! I used the Ballistic Plex for the first time last year and wouldn't ya know it...shot was at 75Yds.

I realy realy do like being able to sight in dead on at 100 Yds though. That way you are witnin 1 1/2" out to about 165Yds. That really helps when you are haveing to thread a shot through brush.

Never had the opportunity to go on an Antelope hunt, but sure would like to!!!

firstshot
----------------------------
Make your first shot count!

quote:

Originally posted by JudgeSharpe:
Hello the campfire:
What I get out of all this is that:
1. You should sight your rifle in at least each year because the zero might have changed due to being knocked around, differant ammo, ect.
2. There are several good ways to sight in and not every one of them is good for everybody else. You need to do whatever you have confidence in.
3. The point is to know where your bullet is going to hit.
4. Each gun and load is different.
5. Practice helps.
6. Everyone should sight his own Rifle because soneone else's zero might not be yours.
7. The first shot counts
8. a hot barrel and a cold barrel might shoot differently. A clean barrel may shoot differently than a dirty one. Know how yours shoots each way.
9. It is hard to judge distance over 100 yards without a range finder.
10. If you are going to hunt with a rifle, know how it shoots under the conditions you hunt in.
11. It does not contribute to the accuracy of a rifle to throw it in the back of the truck and bounce it around, nor does it help to put it under the other gear, let the kids sit on it, drop it in the dirt or sand, or have the sling break and drop it.
12. Learn how to shoot with a sling because you will shoot better. Not all slings are for shoting. Check your slings and swivels because they break.
13 Carry a sighted in back up.
14. Hope for the best, plan for the worst.
This is just my two cents.
Judge Sharpe

Yep.
And if yur huntin two states over yonder, take an extree back-up gun...
And extree bat-trees fur yur rangefonder and gpr...

quote:

Originally posted by Reloader:
Again, I don't disagree that some of you shoot different w/ certain rifle from certain positions but, a well built rifle is going to shoot the same regardless of the position as long as the bbl, stock, and action are not under any stress.
Reloader

I agree mostly with this. However I have shot very good quality rifles that had a shift in point of impact at different positions, floated barrel and all.
And not just with me shooting.

Hello the campfire:
What if one did this:
Shoot 2-3 shots in a hunting position, adjuste the sight to impact properly when shooting in that position, if the group was not good, shoot off the bags to see where the problem is and go from there. I know groups wll not be as tight, but you ned toknow that too.
The point being that the important shot is the first shot in a hunting position.
This is different from shooting to absolute accuracy such as testing loads or putting the scope on paper after it is mounted.
When I shot small bore and high power rifle that is what we would do. Zero with the sling in the required position before shooting for record. No rest alowed, iron sights only.
I think that many times a shooter fools him(her)self shooting off bags into thinking he is a better shot than he is. The accracy there is the function of the bags and is maybe a starting pont, but what you need to know is how you shoot in the common positions, prone, sitting, off hand standing ect. The important thing is how YOU shoot, not the bags.
Judge Sharpe

Judge Sharpe, you sound like my dad. (I mean that in a GOOD way)
It doesn't matter the groups the rifle is capable of if the shooter is not up to task.
Or some variable changes the POI.

Bags and rests are great for load development, checking sights etc., but shooting the gun in actual field conditions is the real test.

If it’s a varminter, bags, a rest or bi-pods are OK if that’s the way it will be used in the field. It should be shot in EVERY way it will be used. It’s amazing how sometimes you can find a difference in POI at different positions. Even with a high-dollar rifle.

A big game hunting rifle should be shot the way it will be used, EVERY way it will be used. Sticks, sling, prone, whatever. Nothing worse than finding out your POI shifts 3†@ 100 yards with a particular set-up on a 300 yard shot…