The graphics below illustrate and compare different common zeros and the impacts they yield at various ranges. The graphics show points of impact for a given zero using various common barrel length and popular ammunition combinations. The trajectories of M193, M855, and Mk262 ammunition is illustrated with velocities adjusted for the given barrel length in an attempt to give most shooters an idea of what their set-up is doing down range. These are meant to be a quick visual reference. There are far too many factors that come into play for these to be 100% accurate for every set up and situation, but they will get you close. Also, keep in mind that these graphics do not take factors such as weapon/ammunition accuracy and shooter error into account. These graphics are based off of 100% perfect conditions and are meant to give you a general idea of where your impacts will be.
The graphics use a standard IPSC target for scale. The red dot is the point of aim with the black dots being the point of impact for the given distance.
Hopefully you guys find these to be helpful as an easy way to see what your chosen zero yields with your set-up.
Iām still working up graphics for 11.5ā, 12.5ā, and 20ā guns and should have them up soon.
I like these better than ballistic charts since they are much easier to read for the kaymen. I usually end up pointing at my chest saying here, here, here.
The graphics above do a decent job of showing the effect of zeroing distance on midrange targets.
There is a lot going on between the muzzle and 200 yards (I really prefer to use meters, but thatās just me and how my data collection goes for things more involved than red-dots), that arenāt captured in these. My critique of them is linked to the degree of precision that common carbines are capable of, and would be expected in competition or life-saving events that have a ballistic solution.
Hereās an example.
Iām showing a B-8 for these because it is a very common target, for a lot of good reasons. It has relevant scoring areas. X-Ring is 1.7 inches in diameter, 10-ring is 3.36 inches. I really like that level of precision for practical carbine use. 9-ring is 5.54 inches, which is good for fast stuff while maintaining decent precision. Keeping things inside an ISPC A-Zone is good, but once the targets get canted or are partially obscured, I like to have a better feel for the trajectory and hold requirement for success.
One could apply this to the head of an IPSC, but that really only pertains to that particular game from a practical standpoint. I donāt want to drag that out, so let me get to the point:
Hereās M855 from a 14.5" barrel, with a 2.6" LOS over bore, at sea level, standard atmosphere.
Big red circle is your POA/POI intersection, depicted about the relative size of a 2 MOA dot at 50 yards/meters (1").
Little white or grey circles are the center of the trajectory at the distances indicated to their right.
0-100 Meter Trajectories
100 Meter Zero:
200 Meter Zero:
300 Meter Zero:
Please bear in mind that with all of these, human error and the baseline accuracy of the firearm being used are not depicted. Most users should be able to hold a 3" group at a decent pace at 25 yards from a standing position, so when you picture these, remember that your shots wonāt necessarily land exactly where the theoretical path indicates. I like to have some leeway in the hold, and I donāt want to be forced into hard hold-over change-over distances. Holds (POA) that cover a lot of ground, with the ability to hit small targets without much mental measuring will make things easier.
Iāll pop back with some 0-100 refinement with each of the major zeroing concept players, as well as some mid-range stuff if anybodyās interested.
Iāve heard some people espousing the benefits of a 37 yard/meter Zero, saying that it gives a good center hit at a wider range that other Zeros. Would it be possible to do the same thing with barrel lengths and a ā37 Zeroā?
Confirmation at distance is what so many people forget about. People are really into short distance/rising branch zeros, which is fine beacuse it takes less time. But most people donāt realize that it isnāt as useful for the windage as it is for elevation. Windage deviations will really show at the far/falling branch end of the zero distance.
Get on paper close, then go confirm at distance and you will be much better off. Rarely does anyone not have to make adjustments when confirming at the farther distance. This doesnāt really apply to the 100m zero as it is quite unique which makes it very useful for certain applications. I am referring to zeroing schemes such as the 25/300m and 50/200m.
I really appreciate all the time and effort that went into making the graphics in this thread.
Interesting; Iād have expected it to be somewhere between the bullet arcs of zeroing at 25 and 50 yards. Would it be confirmation if I were to zero at 2.5 inches high at 100 yards/meters?
But youāve brought up another conundrum, why is there āno confirmation at actual distanceā when zeroing at 37 meters and putting a group on a target at 50, 100, 200, or 300 meters and there is 'confirmation at actual distance when zeroing at 50, or 100 (or pick your favorite) and putting a group on paper at 50, 100, 200, or 300 meters? Or, am I just misunderstanding what you said?
I donāt really care if the zero range is measured in feet, yards, chains, cubits, meters or even Smoots.
What I do care about is having the best ability to put a shot center mass at the widest range of ā¦ ranges, neither too high nor too low with just a glowy red dot as my aiming point. If the trajectory never rises more than 3" nor falls more than 3"below POA all the way out to 250 yards Iāll be a happy camper. The chances of being engaged by someone past that distance are practically nil, and much less for me as a civilian now.
The trajectory of M193 Ball is such that if it passes through zero at 25 meters, it will pass through zero again at 375 meters. Similarly, M855 will pass through zero at 25 meters and 340 meters. This is why when zeroing on a 1000 inch range (25 meters) you are supposed to set your rear sight on āLā for the M16A1 rear sight or ā300/800ā with the small aperture (long range) on the M16A2 type sight.
After you zero at 25 meters, you could āconfirmā that the zero is good at 375 or 340 meters, and this would prove that your ammunition has the muzzle velocity you thought it does, and the bullet has the ballistic coefficient you thought it should.
For a ā37 meterā zero, the āconfirmation rangeā would be dependent on the Vm and B.C. of the particular load, but for M193 it would be about 375 meters and M855, about 300 meters.
The reason for the ā37 metersā zero:
With the Army 25 meter zero, the M193 bullet reaches a maximum of +8.5 inches above the line of sight at about 200 meters and drops below -9 inches at 400 meters. M855 goes to 425 meters with similar maximum. The 37 meter zero holds the maximum rise to about 4 inches and the maximum range to the bullet dropping outside an 8 inch circle is about 300 meters, so, out to 300 meters, the 37 meters zero holds the trajectory in half the diameter circle.
Great thread. I used excel to create a graph showing the relationship of poi relationship relative to a 4moa reddot, which Iāve found helpful using that sight at distance as a makeshift bdc.
Mine is using a 100yd zero and 60gr tap, so itās not directly applicable, but some may find it beneficial to do the same with bbl lengths and ammo discussed here. If you would be interested, someone can pm me the ballistic data for a specific ammo/bbl combo and I could mock one up and add it to the thread.
