AR-15 Zeros And Trajectories

BY Herschel Smith
1 month, 2 weeks ago

Via WRSA, this thread at AR15.com is great.  Thanks to the guy who worked so hard putting this all together.

I got it all the first time around (make sure to study all of the graphs and read the discussion carefully).  If you’re unaccustomed to working with Newtonian physics, it may take you a time or two through it.

My complaint: He addresses only 55 grain bullets, and doesn’t seem to make much of barrel length.  I’d like to see this thread expanded to include 68, 75 and 77 grains.  A lot of guys are shooting heavier bullets now.  That affects velocity, and thus changes everything.

But that’s a minor complaint.  To be sure, I haven’t put together anything like this for readers, so I have no room to complain.  I’m sure he put an awful lot of work into this, so he doesn’t need complaints from the peanut gallery.


Comments

  1. On October 15, 2021 at 11:07 pm, RHT447 said:

    Here’s a good companion video by Travis Haley–

    https://www.youtube.com/watch?v=DFbpjNh4DBA

  2. On October 16, 2021 at 1:36 am, Georgiaboy61 said:

    The Improved Battlesight Zero was invented by a Marine Lt. Colonel Chuck Santose, so it is also sometimes known as the Santose method or system. As the lengthy post at AR15.com makes clear, its chief virtue is that it allows greater versatility out of the standard front sight and rear carry handle sighting system than is typically the case.

    As the article notes, the standard battle-sight system employed by the AR15/M16 and its carbine derivatives, is designed around a 25-meter BSZ (battle-sight zero) for use inside 300 meters, with elevation adjustments made for longer ranges to be done using the elevation wheel, whether the fixed carry handle type 300-800 meters, or the detachable carry-handle 300-600 meter type. Inside 300m, the standard BSZ was to be used, combined with the appropriate adjustment or hold as needed.

    For military use, many believe the 25m BSZ is ideal since at most normal combat ranges inside 300m, the soldier is either holding under to account for his trajectory, or pretty much center-mass, depending on the situation. In either instance, at no time is his front sight blade obscuring the target, as might occur when holding over.

    If memory serves, army doctrine was to teach recruits to hold at the belt-line for most engagement ranges. Any present/former soldiers, feel free to correct that if needed….

    The chief benefit of the Santose Improved Battlesight Zero is that it retains the capabilities of the legacy iron-sighting sighting system,while expanding its versatility inside 300 meters, the distance at which most people – especially civilians – expect to do their shooting. Most ranges are limited to 100, 50 or 25 yard distances, and at least in the U.S. are not graduated in meters (1 meter = 1.09 yards).

    The Revised Improved Battlesight Zero system (RIBZ) simply takes the Santose system a bit further. It allows good 25, 50, 100 and 200 yard zeros, in addition to the normal use of the elevation wheel as before. But you will need a taller-than-stock front sight post for most 20-inch barrel rifles, as the standard post isn’t quite tall-enough.

    For what it is worth, many Marines prefer the 36 yard near-zero as their everyday battle zero or maximum point-blank range setting. The Army, on the other hand, has stayed with its traditional 25m/300m system.

    This debate is now somewhat academic – at least for the military – now that both the Army and Marine Corps have adopted optics as their standard-issue carbine/rifle sights. If there is any standardization to zeroing of BUIS in either of these two branches of service, I am unaware of it.

    Given a decent exterior ballistics program and data for your load, i.e., bullet weight, muzzle velocity and ballistic coefficient, it is easy to dope out what the best maximum point-blank range or BSZ is for your particular set-up. Or, since few civilians – even cops – ever use a carbine for defensive purposes outside of fairly close ranges, put a 100 yard zero on it and call it done.

    For non-tactical uses, use the normal hunter’s maximum point blank range method, which starts with the vital zone on the game animal in question and works backwards from that. If a coyote is assumed to be nine inches deep in the chest or brisket, that’s your vital zone. And so on.

    Competitors in service rifle matches usually employ sights custom-made for this purpose, which allow precise, fine and repeatable adjustment at the appropriate ranges. White Oak Arms, Rock River Arms, etc. make these.

    Herschel, with regard to your question about the heavier bullets now used by many folks, the simplest answer is to dope it out using a ballistics program and whatever data you can generate for your particular set-up. Each load has its own come-ups and particular trajectory characteristics. There’s no escaping having to do the grunt work at the range and in the field if you want to master your trajectory. But hey, the good news is that you are an engineer and have more capability with crunching numbers than most people out there…. so it ought to be a snap for you.

  3. On October 16, 2021 at 5:07 am, Russell G. said:

    “My complaint: He addresses only 55 grain bullets, and doesn’t seem to make much of barrel length. I’d like to see this thread expanded to include 68, 75 and 77 grains. A lot of guys are shooting heavier bullets now. That affects velocity, and thus changes everything.”

    Xactly.

    Get your chrono out for your load and your platform. And, don’t think your an idiot when you blow the top sun shades off…everyone does it at least once an outing.

    You’ll need to burn up lots of rounds to get it dialed in. You just cannot copy and past a drop chart from someone else. You change that **specific** load for your platform (or any atmospheric variables for that matter) and you’re dope is bad. Not so much on a small 200ish yards, but the long shot won’t even be seen.

    Also remember this. Boxed ammo powder is “blended” by lot (to get a velocity **average**), meaning that lot to lot differences will affect your drop chart. Take a look at any 3-4 cans of Accurate powders…notice that they are probably made in different countries. That’s why in the old days reloaders bought the powder in 8 lb jugs and only used that powder in one specific platform. Now, it’s merely hoarding IF you can even find powder.

  4. On October 16, 2021 at 6:33 am, anon said:

    I find this very helpful: https://store.appliedballisticsllc.com/product_p/dl2001.htm

    ballistics engineer developed it.

  5. On October 16, 2021 at 7:37 am, George said:

    If you want to use an internet website try JBM Calculations-Trajectory.
    Short yardage zeroes are a starting point. One must still verify the POI at the various yardages. Some do not have access to ranges with long distance berms. Therein lies the rub.

  6. On October 16, 2021 at 5:46 pm, Georgiaboy61 said:

    @ Russell

    Re: “Get your chrono out for your load and your platform. And, don’t think your an idiot when you blow the top sun shades off…everyone does it at least once an outing.”

    Even if not that, then struggling with an optical chronograph when lighting conditions are not ideal, or there is a stiff wind blowing. Get a Lab Radar doppler radar unit, you’ll be glad you did. Works rain or shine, or when the wind is blowing, and is also considerably more-accurate than most optical chronos. And no screens to shot through or under. The Lab Radar sits to the side of the shooter and his firearm, not downrange some distance.

    It’s somewhat spendy for some people, at around $500, but suck it up and get it…. cry once, be happy thereafter.

  7. On October 16, 2021 at 7:26 pm, JB said:

    The irons on all my 5.56 AR’s are set at at a 36 yard zero. Im pushing 68 and these old eyes need corrective lenses to make good hits out to a 100 yards. I no longer hunt and so heavier loads are not in my SHTF stockpile which is limited to M193 and XM855 for the AR’s. I thank everone for providing useful information on this subject.

  8. On October 17, 2021 at 12:23 pm, Tree Mike said:

    Thanks so much. Best, most comprehensive, tables, info I’ve run across. Now do it for the 300 BO, please ( I know, 300yds is pushing it), or 308/7.62.

  9. On October 17, 2021 at 4:52 pm, X said:

    The rough rule of thumb from service rifle matches is:

    Two to two, three to three, and twelve to six.

    In other words:

    From a 100 yard zero, two minutes elevation to 200 yards

    From a 200 yard zero, three minutes elevation to 300 yards

    From a 300 yard zero, 12 minutes elevation to 600 yards.

    It’s not perfect but it’s “close enough” to get you “in the black.” Furthermore, this works with most service rifles regardless of caliber — 5.56, 7.62, 30-06.

RSS feed for comments on this post. TrackBack URL

Leave a comment


You are currently reading "AR-15 Zeros And Trajectories", entry #28396 on The Captain's Journal.

This article is filed under the category(s) AR-15s and was published October 15th, 2021 by Herschel Smith.

If you're interested in what else the The Captain's Journal has to say, you might try thumbing through the archives and visiting the main index, or; perhaps you would like to learn more about TCJ.

26th MEU (10)
Abu Muqawama (12)
ACOG (2)
ACOGs (1)
Afghan National Army (36)
Afghan National Police (17)
Afghanistan (704)
Afghanistan SOFA (4)
Agriculture in COIN (3)
AGW (1)
Air Force (36)
Air Power (9)
al Qaeda (83)
Ali al-Sistani (1)
America (21)
Ammunition (172)
Animals (117)
Ansar al Sunna (15)
Anthropology (3)
Antonin Scalia (1)
AR-15s (303)
Arghandab River Valley (1)
Arlington Cemetery (2)
Army (80)
Assassinations (2)
Assault Weapon Ban (27)
Australian Army (7)
Azerbaijan (4)
Backpacking (2)
Badr Organization (8)
Baitullah Mehsud (21)
Basra (17)
BATFE (121)
Battle of Bari Alai (2)
Battle of Wanat (18)
Battle Space Weight (3)
Bin Laden (7)
Blogroll (3)
Blogs (23)
Body Armor (21)
Books (3)
Border War (14)
Brady Campaign (1)
Britain (38)
British Army (35)
Camping (4)
Canada (3)
Castle Doctrine (1)
Caucasus (6)
CENTCOM (7)
Center For a New American Security (8)
Charity (3)
China (15)
Christmas (12)
CIA (29)
Civilian National Security Force (3)
Col. Gian Gentile (9)
Combat Outposts (3)
Combat Video (2)
Concerned Citizens (6)
Constabulary Actions (3)
Coolness Factor (3)
COP Keating (4)
Corruption in COIN (4)
Council on Foreign Relations (1)
Counterinsurgency (218)
DADT (2)
David Rohde (1)
Defense Contractors (2)
Department of Defense (191)
Department of Homeland Security (26)
Disaster Preparedness (4)
Distributed Operations (5)
Dogs (12)
Donald Trump (26)
Drone Campaign (3)
EFV (3)
Egypt (12)
El Salvador (1)
Embassy Security (1)
Enemy Spotters (1)
Expeditionary Warfare (17)
F-22 (2)
F-35 (1)
Fallujah (17)
Far East (3)
Fathers and Sons (2)
Favorite (1)
Fazlullah (3)
FBI (32)
Featured (186)
Federal Firearms Laws (18)
Financing the Taliban (2)
Firearms (1,442)
Football (1)
Force Projection (35)
Force Protection (4)
Force Transformation (1)
Foreign Policy (27)
Fukushima Reactor Accident (6)
Ganjgal (1)
Garmsir (1)
general (15)
General Amos (1)
General James Mattis (1)
General McChrystal (44)
General McKiernan (6)
General Rodriguez (3)
General Suleimani (9)
Georgia (19)
GITMO (2)
Google (1)
Gulbuddin Hekmatyar (1)
Gun Control (1,380)
Guns (1,945)
Guns In National Parks (3)
Haditha Roundup (10)
Haiti (2)
HAMAS (7)
Haqqani Network (9)
Hate Mail (8)
Hekmatyar (1)
Heroism (4)
Hezbollah (12)
High Capacity Magazines (16)
High Value Targets (9)
Homecoming (1)
Homeland Security (1)
Horses (1)
Humor (37)
ICOS (1)
IEDs (7)
Immigration (94)
India (10)
Infantry (4)
Information Warfare (2)
Infrastructure (2)
Intelligence (23)
Intelligence Bulletin (6)
Iran (170)
Iraq (379)
Iraq SOFA (23)
Islamic Facism (64)
Islamists (95)
Israel (18)
Jaish al Mahdi (21)
Jalalabad (1)
Japan (2)
Jihadists (80)
John Nagl (5)
Joint Intelligence Centers (1)
JRTN (1)
Kabul (1)
Kajaki Dam (1)
Kamdesh (9)
Kandahar (12)
Karachi (7)
Kashmir (2)
Khost Province (1)
Khyber (11)
Knife Blogging (4)
Korea (4)
Korengal Valley (3)
Kunar Province (20)
Kurdistan (3)
Language in COIN (5)
Language in Statecraft (1)
Language Interpreters (2)
Lashkar-e-Taiba (2)
Law Enforcement (4)
Lawfare (7)
Leadership (6)
Lebanon (6)
Leon Panetta (2)
Let Them Fight (2)
Libya (14)
Lines of Effort (3)
Littoral Combat (8)
Logistics (50)
Long Guns (1)
Lt. Col. Allen West (2)
Marine Corps (271)
Marines in Bakwa (1)
Marines in Helmand (67)
Marjah (4)
MEDEVAC (2)
Media (62)
Medical (112)
Memorial Day (6)
Mexican Cartels (36)
Mexico (52)
Michael Yon (6)
Micromanaging the Military (7)
Middle East (1)
Military Blogging (26)
Military Contractors (4)
Military Equipment (24)
Militia (6)
Mitt Romney (3)
Monetary Policy (1)
Moqtada al Sadr (2)
Mosul (4)
Mountains (25)
MRAPs (1)
Mullah Baradar (1)
Mullah Fazlullah (1)
Mullah Omar (3)
Musa Qala (4)
Music (24)
Muslim Brotherhood (6)
Nation Building (2)
National Internet IDs (1)
National Rifle Association (78)
NATO (15)
Navy (24)
Navy Corpsman (1)
NCOs (3)
News (1)
NGOs (2)
Nicholas Schmidle (2)
Now Zad (19)
NSA (3)
NSA James L. Jones (6)
Nuclear (58)
Nuristan (8)
Obama Administration (221)
Offshore Balancing (1)
Operation Alljah (7)
Operation Khanjar (14)
Ossetia (7)
Pakistan (165)
Paktya Province (1)
Palestine (5)
Patriotism (7)
Patrolling (1)
Pech River Valley (11)
Personal (67)
Petraeus (14)
Pictures (1)
Piracy (13)
Pistol (2)
Pizzagate (21)
Police (549)
Police in COIN (3)
Policy (15)
Politics (915)
Poppy (2)
PPEs (1)
Prisons in Counterinsurgency (12)
Project Gunrunner (20)
PRTs (1)
Qatar (1)
Quadrennial Defense Review (2)
Quds Force (13)
Quetta Shura (1)
RAND (3)
Recommended Reading (14)
Refueling Tanker (1)
Religion (248)
Religion and Insurgency (19)
Reuters (1)
Rick Perry (4)
Rifles (1)
Roads (4)
Rolling Stone (1)
Ron Paul (1)
ROTC (1)
Rules of Engagement (75)
Rumsfeld (1)
Russia (32)
Sabbatical (1)
Sangin (1)
Saqlawiyah (1)
Satellite Patrols (2)
Saudi Arabia (4)
Scenes from Iraq (1)
Second Amendment (442)
Second Amendment Quick Hits (2)
Secretary Gates (9)
Sharia Law (3)
Shura Ittehad-ul-Mujahiden (1)
SIIC (2)
Sirajuddin Haqqani (1)
Small Wars (72)
Snipers (9)
Sniveling Lackeys (2)
Soft Power (4)
Somalia (8)
Sons of Afghanistan (1)
Sons of Iraq (2)
Special Forces (28)
Squad Rushes (1)
State Department (23)
Statistics (1)
Sunni Insurgency (10)
Support to Infantry Ratio (1)
Supreme Court (30)
Survival (58)
SWAT Raids (55)
Syria (38)
Tactical Drills (2)
Tactical Gear (6)
Taliban (168)
Taliban Massing of Forces (4)
Tarmiyah (1)
TBI (1)
Technology (17)
Tehrik-i-Taliban (78)
Terrain in Combat (1)
Terrorism (95)
Thanksgiving (12)
The Anbar Narrative (23)
The Art of War (5)
The Fallen (1)
The Long War (20)
The Surge (3)
The Wounded (13)
Thomas Barnett (1)
Transnational Insurgencies (5)
Tribes (5)
TSA (22)
TSA Ineptitude (13)
TTPs (4)
U.S. Border Patrol (5)
U.S. Border Security (14)
U.S. Sovereignty (17)
UAVs (2)
UBL (4)
Ukraine (3)
Uncategorized (58)
Universal Background Check (3)
Unrestricted Warfare (4)
USS Iwo Jima (2)
USS San Antonio (1)
Uzbekistan (1)
V-22 Osprey (4)
Veterans (3)
Vietnam (1)
War & Warfare (318)
War & Warfare (40)
War Movies (4)
War Reporting (21)
Wardak Province (1)
Warriors (6)
Waziristan (1)
Weapons and Tactics (73)
West Point (1)
Winter Operations (1)
Women in Combat (21)
WTF? (1)
Yemen (1)

November 2021
October 2021
September 2021
August 2021
July 2021
June 2021
May 2021
April 2021
March 2021
February 2021
January 2021
December 2020
November 2020
October 2020
September 2020
August 2020
July 2020
June 2020
May 2020
April 2020
March 2020
February 2020
January 2020
December 2019
November 2019
October 2019
September 2019
August 2019
July 2019
June 2019
May 2019
April 2019
March 2019
February 2019
January 2019
December 2018
November 2018
October 2018
September 2018
August 2018
July 2018
June 2018
May 2018
April 2018
March 2018
February 2018
January 2018
December 2017
November 2017
October 2017
September 2017
August 2017
July 2017
June 2017
May 2017
April 2017
March 2017
February 2017
January 2017
December 2016
November 2016
October 2016
September 2016
August 2016
July 2016
June 2016
May 2016
April 2016
March 2016
February 2016
January 2016
December 2015
November 2015
October 2015
September 2015
August 2015
July 2015
June 2015
May 2015
April 2015
March 2015
February 2015
January 2015
December 2014
November 2014
October 2014
September 2014
August 2014
July 2014
June 2014
May 2014
April 2014
March 2014
February 2014
January 2014
December 2013
November 2013
October 2013
September 2013
August 2013
July 2013
June 2013
May 2013
April 2013
March 2013
February 2013
January 2013
December 2012
November 2012
October 2012
September 2012
August 2012
July 2012
June 2012
May 2012
April 2012
March 2012
February 2012
January 2012
December 2011
November 2011
October 2011
September 2011
August 2011
July 2011
June 2011
May 2011
April 2011
March 2011
February 2011
January 2011
December 2010
November 2010
October 2010
September 2010
August 2010
July 2010
June 2010
May 2010
April 2010
March 2010
February 2010
January 2010
December 2009
November 2009
October 2009
September 2009
August 2009
July 2009
June 2009
May 2009
April 2009
March 2009
February 2009
January 2009
December 2008
November 2008
October 2008
September 2008
August 2008
July 2008
June 2008
May 2008
April 2008
March 2008
February 2008
January 2008
December 2007
November 2007
October 2007
September 2007
August 2007
July 2007
June 2007
May 2007
April 2007
March 2007
February 2007
January 2007
December 2006
November 2006
October 2006
September 2006
August 2006
July 2006
June 2006
May 2006

about · archives · contact · register

Copyright © 2006-2021 Captain's Journal. All rights reserved.