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Discussion Starter #1
I have a couple of Mark IIIs which I bought new. These are among my very favorite guns to shoot, and I have equipped them both with Aimpoint H-1 red dot sights as shown here:



I zeroed the Mark III Target shown above, using the RDS, at 30 feet. It shoots like a dream at that range and can be relied upon to shoot a ragged hole in a target at 30 feet. At 75 feet, due to the zeroing of the Aimpoint, it shoots a hole an inch or so above the bull's eye. I am curious what range most of you zero your iron or optical sights? I picked 30 feet on the notion that this is a plausible range for shooting a bad guy. Do most of you do something similar, or are you zeroing at greater ranges such as 25 yards?
 

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Discussion Starter #3 (Edited)
I zeroed my 22/45 with Bushnell TRS-25 at 25 yards. It is a range gun only, not a SD gun. I practice with my SD guns at 30 feet with open sights though.
Copy that. These are my SD guns:




Among others, at least. I guess I have gotten into the 30 foot habit since that is about the maximum plausible self-defense range for a handgun. :eek:

25 yards with a 22 pistol I find to be somewhat challenging. Maybe I should zero one of my Marks at that range and have some fun. :rolleyes:
 

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I zeroed my 22/45 with Bushnell TRS-25 at 25 yards. It is a range gun only, not a SD gun. I practice with my SD guns at 30 feet with open sights though.
I have been zeroing all of my "range" guns like the Single Ten, MKIII, and 22/45 at 25 yds with iron sights or red dots.

My higher cal SD guns are set at about 30'
 

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Redleg, There's no perfect sight in distance for any scope, Red Dot, or even iron sights. Because the bullet trajectory actually requires the muzzle be pointed up slightly in relation to the scope's line of sight, the bullet will rise until it crosses the line of sight. Depending on sight in distance, the bullet will continue to rise until it reaches the peak then it will start to drop and again cross the line of sight. This means there are always two distances in the bullet's trajectory where the gun is truly "zeroed".

Here's a Ballistic Explorer chart I ran for my scoped MK III using a 40 gr CCI Mini-Mag with a zero-in distance of 25 yards. As you can see, the bullet starts out 3/4" below sight line (distance from the bore line to the scope) then rises and crosses the line of sight at 13.9 yards, reaches peak trajectory at 20 yards, starts dropping and crosses the line of sight again at 25 yds, then continues to drop with increased distance.



What I do is called "channel sighting" where the bullet never gets higher or lower that a specified amount at normal shooting distances. If you look at the chart, the bullet path maintains about +or- 1 bullet diameter (about a 1/2" channel) from 7 yards to 33 yards when zeroed for 25 yards. If you zero-in too close, bullet rise will make shots at 20~25 yards hit way too high. Likewise, if you zero-in too far, close up shots will hit too low. A 1" sight channel (+or-.5") will take you from the muzzle out to 42 yards. A 25 yard zero-in seems to be a good compromise for nearly all normal handgun shooting distances, however if I were shooting continually at a specified distance, I would probably zero-in for that specific distance.
 

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Discussion Starter #6
Great info and thank you!
 

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I keep my red dot equipped MKIII Comp sighted in for 50 feet, which is a standard competition range for rimfire shooting. I'm not actually competing, other than with myself, but that's a good range for a red dot and the small 1" orange stick on dots we like to shoot. 50 feet is also where I shoot my New Bearcat, as the sights on the Bearcat are pretty crude and that's the distance I generally use the Bearcat for plinking, anyway.

On my scoped MkIII Hunter and my Red dot equipped Single Ten, as well as my 1911s and my GP-100, I sight in for 25 yards. That's a good all around sight in distance for pistol shooting, though I also practice quite a bit at 50 feet (16 yards) with the 1911s for self-defense practice. .

On my scoped Charger and my scoped TC Contender 22 LR, I sight in at 50 yards. These are specialty pistols and can easily handle that kind of range.

In other words, having a variety of guns to shoot at my disposal, I have the luxury of choosing a pistol for any given range I expect or want to shoot. If I had only one rimfire pistol, I'd probably go with 25 yards as Iowegan says. With your red dot equipped Mark, you can still easily adjust your red dot hold for accurate shooting at 50 feet and still have capability for the occasional longer shot.
 

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Redleg, There's no perfect sight in distance for any scope, Red Dot, or even iron sights. Because the bullet trajectory actually requires the muzzle be pointed up slightly in relation to the scope's line of sight, the bullet will rise until it crosses the line of sight. Depending on sight in distance, the bullet will continue to rise until it reaches the peak then it will start to drop and again cross the line of sight. This means there are always two distances in the bullet's trajectory where the gun is truly "zeroed".

Here's a Ballistic Explorer chart I ran for my scoped MK III using a 40 gr CCI Mini-Mag with a zero-in distance of 25 yards. As you can see, the bullet starts out 3/4" below sight line (distance from the bore line to the scope) then rises and crosses the line of sight at 13.9 yards, reaches peak trajectory at 20 yards, starts dropping and crosses the line of sight again at 25 yds, then continues to drop with increased distance.



What I do is called "channel sighting" where the bullet never gets higher or lower that a specified amount at normal shooting distances. If you look at the chart, the bullet path maintains about +or- 1 bullet diameter (about a 1/2" channel) from 7 yards to 33 yards when zeroed for 25 yards. If you zero-in too close, bullet rise will make shots at 20~25 yards hit way too high. Likewise, if you zero-in too far, close up shots will hit too low. A 1" sight channel (+or-.5") will take you from the muzzle out to 42 yards. A 25 yard zero-in seems to be a good compromise for nearly all normal handgun shooting distances, however if I were shooting continually at a specified distance, I would probably zero-in for that specific distance.
In the example graph above it looks like it is zeroed in at both 14 and 25 yards. When I'm sighting in a scope how can I tell if the bullet is rising or falling when it hits the target? Do you just move your target closer and farther away and see where it hits. I have never really though about this before but I can see how it could mess someone up when shooting at a distance other than where it was sighted in.
 

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Discussion Starter #9
So from this chart it would appear that if one zeros at 14 yards you will also be close to zero at 25 yards...
 

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Redleg, The above chart was the only one I had stored in Photobucket. I should have taken the time and noticed ... this was made for my MK III using iron sights that are mounted much closer to bore line (3/4") than a scope would be. I just measured my other MK III that has a 2x conventional pistol scope and the center of the scope is 1.5" above the center of the bore. By making the line of sight higher, it makes the chart look much different because the bullet must rise to the line of sight to "zero".

Sorry for the oversight. Here's a more realistic chart for a MK III with a scope sighted in at 25 yds:


Here's a chart for a 15 yd sight-in:



As you can see, sight height above bore line makes a big difference When you compare a 15 yd sight-in versus a 25 yards sight-in, turns out, a 15yd sight-in creates a nice .8"channel channel where the bullet is never more than .4" high or .4" low from 10~46 yds. With a 25 yd sight in, the bullet never goes above the sight line so a .8" sight channel will still be about the same (7~42 yds) but will always be low except at 25 yds. Guess this contradicts my previous post because I didn't use the right chart.

GunLover, Optics can be very confusing and because of my mistake in the previous post, I have managed to add even more confusion. I'm very sorry ... should have taken the time to upload new charts.

Your question is still quite valid though. The trajectory in the previous post is typical of a pistol with iron sights. If you stretched the distance to a 100 yard sight-in with a typical high power rifle, you would see a similar trajectory where the bullet crosses the line of sight on the way up at about 25 yards, peaks a few inches high at about 50 yards, then starts dropping until it crosses the line of sight again at 100 yards on its way down. So which zero is the correct one? Actually both are because no scope has the adjustment range for both distances. When you sight a high power rifle in, it is common to start with a 25 yard zero. When you move the target out to 100 yards, it should be pretty close to zero. This takes advantage of both the "up" path and the "down" path.

I think the biggest confusion factor relates to how high the scope is mounted above bore line. In other words, the higher the scope is mounted, the more the muzzle has to be pointed up to get the bullet to intersect the "sight line". Again. sorry for the confusion.
 
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