Accuracy Is All About Testing And Practice

BY Herschel Smith
1 year, 6 months ago

Our friend Andy at Practical Accuracy has given us an awesome video on the use of 55 gr. bullets in a 7:1 twist barrel.


Comments

  1. On September 12, 2022 at 11:04 pm, Ambiguousfrog said:

    Geez. 586 yds.

  2. On September 13, 2022 at 8:03 am, Russell G. said:

    The faster twist (7T vs 8T) was to accommodate tracer rounds that are longer.

    And, yes…spin drift may show up differently at longer distances but overall accuracy always depends on the projectile and barrel and the harmonics of the whole she-bang. (Note also that he has a non-floating barrel) The issue with “Over stabilization” (faster twist) is pure voodoo.

    As an example, the PMC X-TAC boxed x193 shoots about 4 moa in my Colt 16″ floating barrel, no matter what. Forget it past 100. If I pull the bullets and put in a Hornady bulk FMJBT 55 grain at the same closed case volume (meaning I’m equalizing pressure) I’ll pull that down to sub-MOA at 100 and about 1.5 MOA at 230. OTOH, the PMC Bronze consistently shoots dime size prints out of the box at 100 and about 1.5 at 230 (I do 16 round runs ALWAYs at the end of the yard). More: The OEM PMC X-TAC in my 16″ Roscoe Wylde floating upper goes down range sub MOA at 100 and the X-TAC goes long in that barrel. This stuff is all with the same lower and buffer system.

    Now, loaders know that the ball game gets even better if you move to a Hornady Vmax or Nosler or SIE OTM in the 223/556. And, if you take a projectile out of a good over the counter x193 and put it in a 22-250 REM you will see remarkable accuracy in a run of the mill bolt platform with 12T – 14T barrel.

    And, finally, any weight above 55 grains means trial and error in a 223/556. Ask any reloader. You really have to do a lot of tweeking with powders, jump, etc. for your platform. It’s just one of those things.

    I’m not sure he is a reloader, but the AR is exactly the same as a 22lr bolt gun—you MUST try different boxed ammo to get the best out of it.

  3. On September 13, 2022 at 9:01 am, Herschel Smith said:

    @Russel,

    Yes we’ve discussed the issue with tracer rounds before and why the twist was selected based on that.

    Thanks for the perspective on ammo. I’ve heard others talk up the PMC Bronze before. It comes in .223, not 5.56. Doesn’t matter, of course.

  4. On September 13, 2022 at 1:08 pm, RHT447 said:

    Nothing profound to add, just my particular experience.

    One of my rifles is an AR A2 heavy barrel that I built back in the early ’90’s for NRA Highpower. It has a 1/9 twist

    Another is one of these–

    https://www.gunsamerica.com/923195121/Winchester-Model-70-Heavy-Varmint-223-Rem.htm

    –also 1/9 twist. I shot both rifle with this handload–

    Hornady 75 gr. A-max that I moly-coated over 25 gr. of Varget, seated .010 off the lands for each rifle. Also beyond magazine length for each rifle, so single load only.

    The M70 literally shot bug holes–5 rounds 3/8 inch center-to-center @ 250 yards (shot from a cement bench with 20X Nikon scope).

    I had my doubts about the AR’s 20-inch barrel, but wanted to try it. Shot as I would in a match, prone, with shooting jacket and sling. Was not group, was pattern–a bit over 24 inches @ 200 yards. Someone suggested a Reloader powder, but I never got around to trying it.

    A side note on loading those long A-max bullets. I start them into the case with my bench mounted press–RCBS Jr. and RCBS competition seating die. I finish them with the same die in a Lee hand press. I hold the press inverted so that as the bullet seats up into the case, the powder tends to flow down around the base, and you crush less grains.

  5. On September 13, 2022 at 3:50 pm, Elon Muskox said:

    From Bryan Litz’s Applied Ballistics for Long Range Shooting, Ch. 10, Bullet Stability (p. 155 in the 1st Edn.):

    “… It’s true that higher stability levels do produce a more rigid spin axis that tends to resist bending as the bullet follows its curved trajectory. However, even bullets with very high stability factors will still trace (sometimes called track) very well with the trajectory, the angle will only lag a little more than a slower spinning bullet. An exception to this statement is for very high angles of fire, near 90 degrees, where the bullet would have to turn on its axis abruptly at the apex of the trajectory. Failing to trace is a consideration for artillery shells fired at very high angles because if the shell doesn’t trace, it won’t hit the ground point first which is required to activate the fuse and detonate the charge. Bear in mind that even for such high angles of fire, failure to trace is still uncommon. For the small angles of even the longest range small arms trajectories, it is very easy for the bullet to trace with the trajectory….”

    So “over-stabilization” of small arms projectiles is a complete myth (at least according to Bryan Litz, but what does he know, right?). Which is not to say the shooting community isn’t errantly attaching the term “over-stabilization” to some other legitimate physical property, but I seriously doubt it. I think it’s just a convenient “boogie man” they keep in the bottom desk drawer for whenever they can’t explain what’s gone wrong. But one fact I know to a certainty: it’s not over-stabilization.

    Litz also mentions in that same chapter that competitive shooters sometimes might opt for a more marginally stabilized bullet-barrel combination (he specifically mentions as low as Sg 1.3, with carefully-selected components) because all bullets have imperfections and the negative effects of those imperfections are reduced when the bullet is spun more slowly. But these are competitors chasing marginal gains you aren’t likely to see the effects of unless you and your rifle already are shooting low tenths of an MOA.

    However, the point is not lost on the less astute shooters that competitors do sometimes opt for a slacker twist — and here’s the crux of the biscuit — they’re doing it in the interest of better precision. And if you don’t understand the “why” of competitors using a slacker twist, it’s only one step from there to the “too fast a twist causes over-stabilization” myth.

    Lastly, suggesting that projectile weight alone is responsible for differences in precision is just silly. Andy is implying that dwell time, charge weight, powder characteristics, seating depth/bullet jump, primer selection, and neck tension (et Al) play no appreciable role in determining precision of flight. Hardly a well-thought-out argument.

  6. On September 13, 2022 at 8:43 pm, Andy said:

    Elon- Not sure what video you watched, but I want to correct some of the assumptions made about my thinking in your comment.

    I never implied or claimed that

    “dwell time, charge weight, powder characteristics, seating depth/bullet jump, primer selection, and neck tension (et Al) play no appreciable role in determining precision of flight.”

    because I would certainly agree they do.

    I also never suggested weight alone of a bullet is responsible for accuracy. I think I pretty much showed weight was not the issue as 2 different 55 gr bullets shot drastically different at 100 yards.

    The whole point of the video was fairly simple. 55 grain bullets can be shot accurately and precisely out of a 1/7 twist barrel, but you will have to test your individual rifle to see what works for you.

    On a side note, I prefer 1/8 or 1/9 twist rifles and I have personally not had a problem shooting accurately and precisely with these twist rates and 77 grain bullets out to 1000 yards. I don’t claim to be a great competition shooter, just an average guy observing my personal experiences on YouTube to show what can be done with an Ar15.

  7. On September 13, 2022 at 9:40 pm, Herschel Smith said:

    @Andy. That’s the way I took your simple points. I appreciate the video.

  8. On September 18, 2022 at 1:48 pm, Elon Muskox said:

    “… David Tubb, a winner of several NRA High Power Rifle Championships, was using a .243 rifle with a 1 in 8.5 twist barrel. He wasn’t able to get consistent accuracy until he changed to a rifle barrel with a 1 in 8 twist. The 1/2 twist change made all the difference between winning or losing the match.

    A term we often hear is “overstabilization” of the bullet. This doesn’t happen. Either a bullet is stable or it isn’t. Too little twist will not stabilize the bullet, while too much twist, with a couple of exceptions, does little harm. Faster than optimum twists tend to exaggerate errors in bullet concentricity and may cause wobble….”

    https://web.archive.org/web/20050208065618/http://www.loadammo.com/Topics/July01.htm

RSS feed for comments on this post. TrackBack URL

Leave a comment


You are currently reading "Accuracy Is All About Testing And Practice", entry #31923 on The Captain's Journal.

This article is filed under the category(s) Ammunition,AR-15s and was published September 12th, 2022 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 (275)
Animals (282)
Ansar al Sunna (15)
Anthropology (3)
Antonin Scalia (1)
AR-15s (373)
Arghandab River Valley (1)
Arlington Cemetery (2)
Army (86)
Assassinations (2)
Assault Weapon Ban (28)
Australian Army (7)
Azerbaijan (4)
Backpacking (2)
Badr Organization (8)
Baitullah Mehsud (21)
Basra (17)
BATFE (218)
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 (189)
Federal Firearms Laws (18)
Financing the Taliban (2)
Firearms (1,758)
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 (1,633)
Guns (2,298)
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 (3)
Horses (2)
Humor (72)
Hunting (31)
ICOS (1)
IEDs (7)
Immigration (106)
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 (67)
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 (95)
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 (62)
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 (72)
Petraeus (14)
Pictures (1)
Piracy (13)
Pistol (4)
Pizzagate (21)
Police (648)
Police in COIN (3)
Policy (15)
Politics (969)
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 (491)
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 (668)
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 (52)
Survival (185)
SWAT Raids (57)
Syria (38)
Tactical Drills (38)
Tactical Gear (14)
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 (24)
TSA Ineptitude (13)
TTPs (4)
U.S. Border Patrol (6)
U.S. Border Security (18)
U.S. Sovereignty (23)
UAVs (2)
UBL (4)
Ukraine (10)
Uncategorized (98)
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 (412)
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)

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.