.223/5.56 ballistic information

[The Annoyed Man]

I ran across this web page yesterday: http://aesirtraining.com/home/rifle-zero/. Never let it be said that I'm not willing to learn something new or admit that I've been wrong about something.

I've been an advocate for a long time of the 25 yard "battle zero" for AR15 carbines. That was based primarily on two things: reading I've done, and using a 25 yard tactical bay at Elm Fork to zero my carbine in. The stats said that if I zeroed at 25 yards, my bullet would recross the point of aim at about 350 yards. Unfortunately, I lacked a place where I could test this in incremental steps beyond 100 yards, so I was never able to confirm for myself that this would be the case; and I also never (shame on me) bothered to look at the ballistic tables for height of trajectory at its apex. Boy was I wrong.

This website avocates what it calls the "Santos Improved Battlesight Zero" (I still don't know who "Santos" is...) for M193 55 grain ball ammo. It compares what happens to bullet climb and drop at zeros of 25, 50, and 100 yards, and it arrives at some interesting conclusions. (The results for 62 grain M855 aren't that much different apparently, and needless to say, hunting ammo in the 55-62 grain range will probably work just as well for these purposes.)

About the 25 yard/meter zero, it says:

"This zero produces a point of aim, point of impact at 25 meters, and again at approximately 382 yards. This trajectory "peaks" at approximately 200 meters, and 9 inches HIGH from the point of aim."

Here's what is says about the "Santos Improved Battlesight Zero:

"This zero produces a point of aim, point of impact at 50 yards, and then again at approximately 225 yards. This zero only produces a "peak" about 2 inches high between 125 and 150 yards."

Therefore, the 50 yard zero means that the bullet's point of impact is never going to be more than 2" below the point of aim between 0 and 50 yards, or never more than 2" above the point of aim between 125-150 yards and 225 yards. That's only a 4" total vertical change in trajectory all the way out to 225 yards. That means that, barring something in the way (hostage or barrier) or weather conditions, you can pretty much guarantee (assuming a rifle of good accuracy) a head shot on a man-sized target all the way out to 225 yards using POA with a decent optic; and you can pretty much guarantee a killing or disabling body body shot on a man-sized target all the way out to 225 yards with just iron sights. Your POI will never be more than 2" high or 2" low at any distance out to 225 yards. Even a 100 yard zero has less bullet climb and drop—from -2 to 0 out to 100 yards, and from 0 to -4 from 100 out to 230 yards—than does a 25 yard zero.

The point is that a 25 yard zero is not the best zero because the bullet has to climb too steeply to cross the POA at that short of a distance, which causes it to be 9" high at the apex of its arc, and that is not really a useful trajectory. If you incline the optic/sights less steeply relative to the bore and obtain a 50 yard zero, you get much smaller deflections in trajectory above and below the POA. This makes the 50 yard zero a much more useful choice for the caliber, and well within its effective range, without having to worry about hold-offs. That makes for a more efficient battle weapon, better at snap-shooting, and even better for hunting. It's just better all the way around for real-world use because it is simpler. Of course, this will be affected by your individual rifle's inherent accuracy. If your rifle will only shoot 4 MOA at 100 yards, then none of this matters. Fortunately most AR15s are inherently more accurate than that. I would urge anyone to test your personal weapon at 50 yards to see if you can maintain decent accuracy at that distance, just to be sure, but this "Santos" thing seems like a much better way of doing it, and my own carbine is fairly accurate so I have confidence that this approach would work well for me.

Fortunately, I can test this at the 100 yard mark, where I would expect to see bullet impacts 1.4" above point of aim with a 50 yard zero. If that turns out to be the case, then I'll have to take the 225 yard POI/POA on faith until I can actually test it, but it gets a lot easier to have that faith.

I'm going to re-zero my EOTech for 50 yards on my next trip to the range.

Anyway, I just thought I would share this information with you guys.

[TheDude]

Great info as usual TAM. Just like you I have the EOTech on my M&P 15 zeroed at 25 yards. I definitely will be re-zeroing at 50 yards first chance i get.

[Jumping Frog]

I liked your summary, but I really liked reading the article as well. I enjoy charts and tables -- it helps me to visualize.

[eureka40]

Excellent info!! Thanks TAM.

[rentz]

great info, i should go to elm fork and zero in at 50.
Never thought about the rifle ranges for carbine since they say hollow points only.

[The Annoyed Man]

great info, i should go to elm fork and zero in at 50.
Never thought about the rifle ranges for carbine since they say hollow points only.

More correctly, they don't allow FMJ on the 100 yard line. Anything else is fine. Monarch makes a 55 grain soft point that shoots pretty much just like M193 ammo. That's what I used on the 100 yard line at Elm Fork.

I liked your summary, but I really liked reading the article as well. I enjoy charts and tables -- it helps me to visualize.

Yeah, I liked the charts too.

[texasmusic]

I used a 100yd zero on my TR24 AR. It worked well as the bullet is always below POA except for 100yds (doesn't cross POA). So the bullet was never more than 3" or so below out to 100. Took some of the guesswork out of ranging targets since you were either on the tip of the triangle or inside of it at all reasonable distances. Unfortunately a man took that rifle away and left me with some 2 wheeled contraption.

[Heartland Patriot]

The funny thing is, that I already have my AR zeroed for 50 yards, but not exactly for that line of thought. Living in suburbia, I tried to imagine (wild imagination/worst case scenario) how far I'd reasonably expect to shoot it. Somehow I got a 50 yard distance in my mind. I used some ballistic "calculators" online, saw the rise and drop numbers were small and went with it. I just saw the numbers, though...I never got to see it like a graph. It makes even more sense that way. Thanks for sharing TAM, now I feel good about the decision I made.

[WildBill]

Isn't there an "app" or program out there that calculates ballistics such as bullet drop?

[The Annoyed Man]

The funny thing is, that I already have my AR zeroed for 50 yards, but not exactly for that line of thought. Living in suburbia, I tried to imagine (wild imagination/worst case scenario) how far I'd reasonably expect to shoot it. Somehow I got a 50 yard distance in my mind. I used some ballistic "calculators" online, saw the rise and drop numbers were small and went with it. I just saw the numbers, though...I never got to see it like a graph. It makes even more sense that way. Thanks for sharing TAM, now I feel good about the decision I made.

You'll notice that the page's author makes the point that even LEOs and soldiers in a MOUT environment would seldom need to fire a carbine past 50 yards. It is good to have the option to shoot beyond that distance if necessary, but for most people, the ability to have faith in their ability to hit out to 225 yards is a good thing. I love shooting my long range .308s, but they are not very useful in an urban environment.

[The Annoyed Man]

Isn't there an "app" or program out there that calculates ballistics such as bullet drop?

Yes there is, but to be effective, you have to know the actual range to target. I have such an app on both my iPhone and iPad, but it would not be usable if you were actually under fire. I wouldn't want to take my eyes off of whomever is shooting at me long enought to calculate bullet drop with a computing device. That's why knowing in advance that you've only got 2" above and below the line of sight to worry about out to 225 yards is so valuable.

[javieljb]

Very nice link. Thanks.

I've used this one below when sighting in my Nikon. I was really impressed with the options and the ability to print out a ballistics report.

http://www.nikonhunting.com/spoton/" onclick="window.open(this.href);return false;

[MoJo]

Isn't there an "app" or program out there that calculates ballistics such as bullet drop?

There sure is! It's called Remington Shoot You can pick the range you want to zero and the distance you can or want to shoot at and it will tell you how much high or low at that range you need to be to be zeroed at the chosen range. It will also generate charts to graph your trajectory and or bullet drop. To zero an M193 round at 225 yards using a 25 yard target it says to zero 0.26" low.

[donkey]

This website avocates what it calls the "Santos Improved Battlesight Zero" (I still don't know who "Santos" is...) for M193 55 grain ball ammo. It compares what happens to bullet climb and drop at zeros of 25, 50, and 100 yards, and it arrives at some interesting conclusions. (The results for 62 grain M855 aren't that much different apparently, and needless to say, hunting ammo in the 55-62 grain range will probably work just as well for these purposes.)

That would LTC Santose, U.S. Army (retired). He serves on the Board of Directors for the F.I.R.E Institute. They have a short bio on him on their site.

[The Annoyed Man]

This website avocates what it calls the "Santos Improved Battlesight Zero" (I still don't know who "Santos" is...) for M193 55 grain ball ammo. It compares what happens to bullet climb and drop at zeros of 25, 50, and 100 yards, and it arrives at some interesting conclusions. (The results for 62 grain M855 aren't that much different apparently, and needless to say, hunting ammo in the 55-62 grain range will probably work just as well for these purposes.)

That would LTC Santose, U.S. Army (retired). He serves on the Board of Directors for the F.I.R.E Institute. They have a short bio on him on their site.

There it is. Thanks for the info. Here's the link: http://www.fireinstitute.org/fire_board ... ectors.htm" onclick="window.open(this.href);return false;

Here's his bio:

Charles F. Santose is a Lieutenant Colonel in the Army of the United States (Retired). He entered service as an infantryman in 1966; he was commissioned through the infantry officer candidate school and commanded infantry and Long Range Reconnaissance Patrol platoons in the Republic of Vietnam. He is both Airborne and Ranger qualified and served two tours as an instructor at the Ranger School at Fort Benning, GA. After release from active duty he served as a full time, professional operations and training officer supervising reserve training and was directly responsible for the individual and unit training of battalion and brigade sized units. Col. Santose is a graduate of, and has taught at, the Command and General Staff College, and was assigned as Director of Leadership at the U.S. Army Signal School during Desert Storm. An avid shooter, Colonel Santose has an in-depth understanding of small arms and their direct use under stress in a wide variety of climatic conditions, and the terminal ballistics of firearms projectiles. Since his retirement from military service, the colonel has worked as director of human resources in the Cleveland area. His military perspective on firearms training gives another dimension to the F.I.R.E. Institute Board.