Discussion On Custom AR-15 Barrels

BY Herschel Smith
5 years, 6 months ago

Shooting Sports USA:

Custom barrel manufacturers like Obermeyer, Krieger, Lilja, Hart, Douglas, Schneider and other companies which go by the maker’s last name, are your best assurance of good quality. That’s not to say that other maker’s barrels―let’s call them “semi-custom”―don’t shoot as well, but it is to suggest a lower element of risk involved in your satisfaction. I think it’s wise to request a stainless steel barrel since they will, on average, shoot a little better for a little longer.

It would be nice if a materials engineer and/or a highly experienced gunsmith would weigh in on this, but that’s not my understanding.  My understanding (which might be flawed) is that a SS barrel will be more accurate out of the box, but that whereas another barrel might last for 25,000 rounds, a SS barrel will last for 15,000 rounds before needing to be replaced.  Again, if my understanding is wrong on this, it would be good to know it.

The chambering option that probably gets the most thought about and worry over is throating. Throating, let’s say here for simplicity, controls the distance of a bullet; bearing surface to the origin of the lands of the rifling. Almost always, a rifle shoots best when a bullet at least starts near the lands, if not on them. If the bullet has to travel through space before engaging the rifling, that’s called “jump,” and that’s an issue of concern. Since there is such a difference in comparing length of short range and long range bullets for this rifle, some compromise has to be met. Essentially, getting less jump for the shorter 68- to 77-grain bullets fired from magazine-length rounds means that the longer 80-grain bullets used at 600 yards will be seated more deeply into the case (which will reduce powder capacity). Short or long? Either, or anything in-between for that matter. It doesn’t really seem to matter. Why even talk about it? Why not? Everyone else does. What they’re not really talking about, though, is who’s shooting what scores with various ideologies. That’s because AR-15s shoot just as well at 200 and 300 yards with all the different “magazine” bullets, regardless of where those bullets are sitting with respect to distance from the lands. What matters to 600-yard performance is that the shooter knows how to experiment and adjust the amount of jump the 80-grain bullets have, and that discussion is for another article.

Someone care to elaborate what’s he’s talking about here?


Comments

  1. On May 13, 2019 at 11:18 pm, Ratus said:

    The stainless steel used to make barrels is “soft” (ie. Better for machining with less tool wear) so cut rifling is more precise and easier to finish. If you are interested in a barrel for competition shooting at targets for score then a high priced “named” barrel is for you.

    On the second part, he’s talking about how chamber dimensions affect accuracy when shooting ammunition that has an OAL the is too long to fit in an AR15 magazine.

    Again, more competition specific frippery that doesn’t really matter to most of the people looking for a good general purpose AR15 barrel.

    If you want me to elaborate more on this just let me know. (Caveat, I’m not an expert in this or any other field. Just someone who has read a lot and has shot a bit)

  2. On May 13, 2019 at 11:31 pm, Ratus said:

    Here’s some links to the very good interview by InrangeTV with Faxon about barrel making.

    Faxon Q&A: Barrel Manufacturing, Nitride vs Chrome lining
    https://youtu.be/e2X1iaQbjg8

    Faxon Q&A #2: Barrel profiles, length, fluting
    https://youtu.be/yF4g2CWtjOo

    Faxon Q&A #3: Twist rates, stress, break-in, gas ports
    https://youtu.be/R3FDLiWMUTc

    Faxon Q&A #4: Chamber types, heat dissipation, headspace
    https://youtu.be/ZDvLrvEAhkM

    Also a short video testing a modern pencil barrel vs an original Colt pencil barrel

    WWSD: Pencil barrel Stress & Heat Zero Testing
    https://youtu.be/QTovPt4weIs

  3. On May 14, 2019 at 4:46 am, Bill said:

    What Ratus said… First off, I’m neither a Gunsmith, nor an Engineer, but I have competed in long range rifle, and have a good experience base with ARs, even building them for various purposes. So…
    The whole “jump to the lands” discussion is purely a Mid to Long Range Competition issue. Competitors have generally (not universally) found benefits to loading their bullets “into” (touching) the lands in the throat of the barrel (thus eliminating the “jump” to the lands when fired, and more importantly aligning the centerline of the bullet with that of the bore). This can also create pressure issues in the rifle & has to be done with care. Nothing about it should concern an AR builder at all, …unless he’s building specifically for long range (which I would not with std AR cartridges).
    The barrel question is endless, and opinions are like -err- “rearward orifices”; everyone has one & they all stink in one way or another.
    The AR platform is so versatile that what is “good” or “bad” depends mostly on your intended use of the rifle. What’s good for a patrol rifle will not be for a varmint rig, or a historical replica. Decide what you want to end up with, then build it. The guy you quoted is thinking solely about competition; a fairly narrow requirement set.

  4. On May 14, 2019 at 10:04 am, Bram said:

    Are Polygonal rifle barrels dead? I always used to hear about the advantages and would have thought they would be popular in this age of expensive customization.

  5. On May 14, 2019 at 12:17 pm, Georgiaboy61 said:

    Re: “The chambering option that probably gets the most thought about and worry over is throating. Throating, let’s say here for simplicity, controls the distance of a bullet; bearing surface to the origin of the lands of the rifling. Almost always, a rifle shoots best when a bullet at least starts near the lands, if not on them. If the bullet has to travel through space before engaging the rifling, that’s called “jump,” and that’s an issue of concern.”

    To second what others have covered, a competition-type stainless steel barrel with a Wylde or similar “tight” chamber is generally what someone doing CMP/NRA high-power rifle would want. It isn’t necessarily best for a general-purpose platform.

    Military-specification rifles and carbines are built with generous chamber dimensions since they may be called upon to fire a wide variety of ammunition, whose length, weight and construction may vary considerably. This is also the case for any select-fire weapons platform since full-auto operation also calls for generous chamber and throat dimensions for optimal reliability.

    Bullet “jump” from the cartridge case (neck) to the lands-and-grooves does not always spell less-accuracy. Some rifles shoot certain loads extremely-well even though there is considerable distance between the projectile and the barrel grooves. The dimensions of the bullet itself, the uniformity of its case, the chamber throat and more – all influence accuracy and reliability.

    For most shooters, the only practical way to discover whether your particular cartridge/bullet and rifle combination “likes” jump or not is to do real-world (empirical) testing at the range.

    Having provided the usual disclaimer that every rifle is different, it is standard practice amongst metallic reloaders to increase COAL (cartridge over-all length) by seating the bullet further out in the case neck, so that it has less distance to travel to engage the rifling. Again, the “sweet spot” is best determined by experimentation.

    The time/effort required for such experimentation benefits long-range or other precision shooters, but is probably not worth it for the typical carbine user, most of whose shots fall inside 100 yards. There just isn’t enough of a payoff realized by shrinking its groups from 1.5-2 inches at 100 yards, to 0.75 inches at the same distance. As always, ask yourself: “How much accuracy do you need?” and don’t let the perfect be the enemy of the good.

  6. On May 14, 2019 at 12:23 pm, elysianfield said:

    Ratus,
    I once manufactured precision rifle barrels…in the early ’90’s. The answer as to whether 416SS barrels are “more accurate” than various steel offerings was a simple matter then;

    “How many stainless steel barrels were successful in the National Bench Rest competitions?

    …None. All the winners used chrome-moly barrels. May be different now?

  7. On May 14, 2019 at 3:32 pm, Georgiaboy61 said:

    @ elysianfield

    No kidding!? The things one learns in everyday life…. thanks for the info.

  8. On May 17, 2019 at 2:45 pm, Guest said:

    In the case of 5.56mm the point is moot. A milspec 5.56mm chamber has 0.162″ of unrifled “leade” in front of the chamber as a means of boosting velocity while reducing maximum pressure peaks. You can’t seat any .224″ diameter bullet I know of anywhere near the rifling, not at cartridge overall length that will fit in an M16 magazine.

    I am aware that benchrest shooters have long favored seating the bullet in such a manner that it just barely kisses the rifling when chambered. You can’t do this here.

RSS feed for comments on this post. TrackBack URL

Leave a comment


You are currently reading "Discussion On Custom AR-15 Barrels", entry #21236 on The Captain's Journal.

This article is filed under the category(s) AR-15s,Firearms,Guns and was published May 13th, 2019 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 (40)
Air Power (10)
al Qaeda (83)
Ali al-Sistani (1)
America (22)
Ammunition (285)
Animals (297)
Ansar al Sunna (15)
Anthropology (3)
Antonin Scalia (1)
AR-15s (379)
Arghandab River Valley (1)
Arlington Cemetery (2)
Army (87)
Assassinations (2)
Assault Weapon Ban (29)
Australian Army (7)
Azerbaijan (4)
Backpacking (3)
Badr Organization (8)
Baitullah Mehsud (21)
Basra (17)
BATFE (229)
Battle of Bari Alai (2)
Battle of Wanat (18)
Battle Space Weight (3)
Bin Laden (7)
Blogroll (3)
Blogs (24)
Body Armor (23)
Books (3)
Border War (18)
Brady Campaign (1)
Britain (38)
British Army (35)
Camping (5)
Canada (17)
Castle Doctrine (1)
Caucasus (6)
CENTCOM (7)
Center For a New American Security (8)
Charity (3)
China (16)
Christmas (16)
CIA (30)
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 (210)
Department of Homeland Security (26)
Disaster Preparedness (5)
Distributed Operations (5)
Dogs (15)
Donald Trump (27)
Drone Campaign (4)
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 (39)
Featured (190)
Federal Firearms Laws (18)
Financing the Taliban (2)
Firearms (1,800)
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 (1,674)
Guns (2,340)
Guns In National Parks (3)
Haditha Roundup (10)
Haiti (2)
HAMAS (7)
Haqqani Network (9)
Hate Mail (8)
Hekmatyar (1)
Heroism (5)
Hezbollah (12)
High Capacity Magazines (16)
High Value Targets (9)
Homecoming (1)
Homeland Security (3)
Horses (2)
Humor (72)
Hunting (41)
ICOS (1)
IEDs (7)
Immigration (114)
India (10)
Infantry (4)
Information Warfare (4)
Infrastructure (4)
Intelligence (23)
Intelligence Bulletin (6)
Iran (171)
Iraq (379)
Iraq SOFA (23)
Islamic Facism (64)
Islamists (98)
Israel (19)
Jaish al Mahdi (21)
Jalalabad (1)
Japan (3)
Jihadists (81)
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 (7)
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 (6)
Lawfare (14)
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 (280)
Marines in Bakwa (1)
Marines in Helmand (67)
Marjah (4)
MEDEVAC (2)
Media (68)
Medical (146)
Memorial Day (6)
Mexican Cartels (41)
Mexico (61)
Michael Yon (6)
Micromanaging the Military (7)
Middle East (1)
Military Blogging (26)
Military Contractors (5)
Military Equipment (25)
Militia (9)
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 (25)
Muslim Brotherhood (6)
Nation Building (2)
National Internet IDs (1)
National Rifle Association (97)
NATO (15)
Navy (30)
Navy Corpsman (1)
NCOs (3)
News (1)
NGOs (3)
Nicholas Schmidle (2)
Now Zad (19)
NSA (3)
NSA James L. Jones (6)
Nuclear (63)
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 (73)
Petraeus (14)
Pictures (1)
Piracy (13)
Pistol (4)
Pizzagate (21)
Police (656)
Police in COIN (3)
Policy (15)
Politics (981)
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 (495)
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 (37)
Sabbatical (1)
Sangin (1)
Saqlawiyah (1)
Satellite Patrols (2)
Saudi Arabia (4)
Scenes from Iraq (1)
Second Amendment (687)
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 (62)
Survival (201)
SWAT Raids (57)
Syria (38)
Tactical Drills (38)
Tactical Gear (15)
Taliban (168)
Taliban Massing of Forces (4)
Tarmiyah (1)
TBI (1)
Technology (21)
Tehrik-i-Taliban (78)
Terrain in Combat (1)
Terrorism (96)
Thanksgiving (13)
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 (25)
TSA Ineptitude (14)
TTPs (4)
U.S. Border Patrol (6)
U.S. Border Security (19)
U.S. Sovereignty (24)
UAVs (2)
UBL (4)
Ukraine (10)
Uncategorized (99)
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 (419)
War & Warfare (41)
War Movies (4)
War Reporting (21)
Wardak Province (1)
Warriors (6)
Waziristan (1)
Weapons and Tactics (79)
West Point (1)
Winter Operations (1)
Women in Combat (21)
WTF? (1)
Yemen (1)

November 2024
October 2024
September 2024
August 2024
July 2024
June 2024
May 2024
April 2024
March 2024
February 2024
January 2024
December 2023
November 2023
October 2023
September 2023
August 2023
July 2023
June 2023
May 2023
April 2023
March 2023
February 2023
January 2023
December 2022
November 2022
October 2022
September 2022
August 2022
July 2022
June 2022
May 2022
April 2022
March 2022
February 2022
January 2022
December 2021
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 © 2006-2024 Captain's Journal. All rights reserved.