200 yd zero

[Don Fischer]

I read about this quite a bit. But I have never heard anyone explain the theory behind it. Could someone do that?

 

[Walkathon]

For me a 200 yard zero makes sense. My longest shots are 300 yards. Most of my shots are 150- 250 yards. For my guns the drop is 7"-9" at 300 yards. No problem with holding over this amount at 300 yards and I'm not terribly high at 100 yards (2" or less). I shoot a 7mm Rem Mag and a .270 Win. Don't know about the theory behind the 200 yard zero, but I'm guessing it has something to do with the lack of adjustable turrets that was common 20 years ago.

 

[VAspeedgoat]

I generally like 3" high at a hunded. Then its point and shoot for my self imposed 300 yard limit. At no point is my .270 over or under 3" in that range. Thats good for any big game animal I hunt. Similar mindset for a 200 yd zero.

 

[Colberjs]

I don't remember the technical term for it but I read an article on it several years ago and they also called it "pipe zero". Basically you choose a "pipe" diameter, say 8", and there is a certain point where you can zero your rifle and it will hit somewhere inside that 8" circle all the way out to "X" amount of yards. I'll see if I can find a chart for it I saw a long time ago telling you what those yardages are for different size circles and different calibers.

 

[Colberjs]

Maximum Point Blank Range. Here is an article I found on it that helps explain it. (Hopefully I'm not breaking any rules posting the link here. If so, admin may feel free to delete it.)

http://www.backcountrychronicles.com/maximum-point-blank-range/

 

[JohnCushman]

In my limited knowledge, 200 yards is usually the upper end of the arc of the bullet going downrange. So, zeroing at 200 gives you the true 'zero' of the path of the bullet height. Then it's just a matter of a little hold at 200 and less or more.

Nevermind this...I was proven wrong. That's why I was a medic and not a sniper

 

[VikingsGuy]

I think serves as a simple one step, no calculation, method that gets you reasonably close to a mpbr for common rounds. I view the extra 3 minutes to calculate and understand your mpbr worth it, but there are a lot of opinions on this topic.

 

[Don Fischer]

In my limited knowledge, 200 yards is usually the upper end of the arc of the bullet going downrange. So, zeroing at 200 gives you the true 'zero' of the path of the bullet height. Then it's just a matter of a little hold at 200 and less or more.

Upper end of the arc? Is that the mid range height? And after that do they start adjusting by moving the turret's? Sounds screwy to me but if it work's for them, more power to them. Some scope have hash marks that are suppose to be aiming point's at different yardages. How can they possibly determine the place for the marks on all rifle's like that? What do they call that zero at 200 yds program?

I have been using MPBR for a lot of years and I usually set it for a 6" target. The max range in fact the zero range is farther than I shoot to begin with.

 

[VikingsGuy]

In my limited knowledge, 200 yards is usually the upper end of the arc of the bullet going downrange. So, zeroing at 200 gives you the true 'zero' of the path of the bullet height. Then it's just a matter of a little hold at 200 and less or more.

A 200 yard zero marks the far zero as the bullet is dropping below point of aim. Since the bullet begins below the scope at the point of trigger pull, it starts below the point of aim. The rifle/scope setup sends the bullet angling slightly up (thereby initiating the "arc" we visualize when we think about bullet ballistics) and goes from -1.5" at muzzle to the near zero at about 40-50 yds or so out with a typical centerfire round. It peaks 2" or so high at somewhere in the 140's/150's yds and reaches the far zero on a downward trajectory at 200 yds and is below the point of aim from there until it hits something.

 

[JohnCushman]

I'm sorry, guys. Thanks for correcting me. This is why I'm mostly an archery hunter I can shoot the hell out of a rifle and do well at long distance, I just don't know the why's and how's of the math of it.

 

[VikingsGuy]

I'm mostly an archery hunter

I don't do much archery, but when I do I really like having the whole scene play out in front of you. You can see the arc from bow to animal and see the hit. Rifles happen so fast and with bigger calibers scope jump takes your eye off the animal for an important moment, and the animal is often quite in the distance. The is something very "by your own hands" about bow hunting that is lost with modern high power rifles and fancy scopes.

 

[Millsworks]

There are lots of so called zero systems that guys use. As long as you understand your set up and verify your point of impact at all ranges you plan on shooting, they all work. It can be as simple or as complicated as you make it.

Shooting the actual yardage is crucial at distances over 300yrds. to be sure of the drop and that goes for dialed turrets, ballistic reticuls, and ballistic apps, even chrono verified loads need to be shot to know your actual drop. This is the only way to make a reliable drop chart.

But, what most don't take into consideration is the accuracy of a 200 plus zero. A rifle zeroed at only 100yrds can leave lots of room for error. You could easily be a quarter inch off left or right or diagonally at a hundred and not know. That nothing much to worry about at 200 but at 400, 600, etc ... it adds up.

A 200 yrd or more zero means less margin for error and a more perfectly aligned set up. If groups are good and tight at 200, then you are likely dialed in.

You may have more drop at 300 than you think. Most would be surprised at how much drop you can have than what a ballistic calculation or , especially factory ballistic chart says it should be.

Barrel length, twist rate, and in many instances barrel diameter of the rifling can and will vary point of impact. Now throw in throat depth and wear, new barrel, old barrel, stainless, mild steel, chrome lined, carbon wrapped, and Lord knows what.

You get what I mean.

If you think your likely to shoot 300 or 400 , you might better shoot some paper targets at those ranges before calling it good.
Medium caliber rifles that go 2,600 or less in speed are more susceptible to serious veriation. But any caliber at any speed can very enough to be problematic.

Ammo is cheap. Burn some powder at the range and know before you go out. You might be surprised and you might not. But , you're likely going to be glad you checked.

 

[VikingsGuy]

A rifle zeroed at only 100yrds can leave lots of room for error. You could easily be a quarter inch off left or right or diagonally at a hundred and not know. That nothing much to worry about at 200 but at 400, 600, etc ... it adds up.

This is an important point, regardless of where/how you initially zero, eventually shooting out 200 or 300 yds really starts to give you enough distance to see some of the smaller biases that may just look like normal variation at 100 yds.

 

[Sask hunter]

Lots depends on the calibre too. I zero my 300 mag at 275 and that puts me 2.5" high at 100

 

[grandejuan]

I've found that my groups are often better at 200 yds than at 100. If I get 1" groups at 100, I've found my 200 yd groups are often still 1". At 300 they are 1.5-2.0" if there is not much crosswind blowing. I don't know if the bullets haven't quite gone to "sleep" at 100 could cause this? I shoot .338 Nosler partition 250 gr bullets from my .340 Weatherby mag at 3050 fps and have had similar results from my .270 Weatherby mag shooting 140 gr Failsafe bullets at 3300 fps. If anything my .270 groups are about .2" tighter at distance than the .340 groups. Have any of you seen similar results? I've not shot the longer mono metal bullets and wonder if twist rates factor in? Both of my barrels are Douglas premium match barrels with 1 in 10 twists. GJ

 

[cahunter805]

GJ
It has been tested and proven that bullets can have some considerable pitch and yaw when they leave the muzzle which can increase drag on the bullet. It is damped out in flight but the effects on trajectory are to small to cause any effects on angular dispersion aka group sizes.

Another factor people forget is parallax. Is your scope adjustable objective? If not most are set to 200 yards from factory which can be a factor in group size also.

 

[grandejuan]

cahunter, thanks for the info. I 've gotten round holes at 100, so they do seem to fly better down range and hold group integrity. GJ

 

[Brian in Montana]

I imagine the "theory" you talking about is maximum point blank range.

I wouldn't really worry too much about the theory behind sighting in, just think in terms of what's practical to your needs. Back when I lived in Texas, I mostly hunted thick brush country with intermittent open areas that were generally not much bigger than an acre. I zeroed at 100 yards because most shots I took were about that, give or take 50. Montana is rather different from TX. The average shot I take out here is around 200 yds, but its not uncommon to shoot 250 to 300 yards. I zero everything about 3 inches high at 100 yards. It's easy to estimate when an animal is within 100 yards and to shoot a little low. Then at longer ranges, like 200 to 250, I'm pretty much right on. I seldom shoot farther than 300. A few times.

 

[Dr. Vette]

I've found that my groups are often better at 200 yds than at 100. If I get 1" groups at 100, I've found my 200 yd groups are often still 1". At 300 they are 1.5-2.0" if there is not much crosswind blowing. I don't know if the bullets haven't quite gone to "sleep" at 100 could cause this? I shoot .338 Nosler partition 250 gr bullets from my .340 Weatherby mag at 3050 fps and have had similar results from my .270 Weatherby mag shooting 140 gr Failsafe bullets at 3300 fps. If anything my .270 groups are about .2" tighter at distance than the .340 groups. Have any of you seen similar results? I've not shot the longer mono metal bullets and wonder if twist rates factor in? Both of my barrels are Douglas premium match barrels with 1 in 10 twists. GJ

GJ
It has been tested and proven that bullets can have some considerable pitch and yaw when they leave the muzzle which can increase drag on the bullet. It is damped out in flight but the effects on trajectory are to small to cause any effects on angular dispersion aka group sizes.

Another factor people forget is parallax. Is your scope adjustable objective? If not most are set to 200 yards from factory which can be a factor in group size also.

cahunter, thanks for the info. I 've gotten round holes at 100, so they do seem to fly better down range and hold group integrity. GJ

Bryan Litz did some extensive testing on this back in 2014:
http://www.longrangehunting.com/threads/applied-ballistics-shoot-thru-target-challenge.144359/

In the end, this was debunked. The short answer was that a longer ranges we aim small, and miss small. Read the thread above if you want all of the details.

 

[mtmuley]

What Corvette you driving? mtmuley