5.56 twist rate

Brutus · July 2, 2016, 09:08 AM

I have a Bushmaster V-match, will the 24" barrel with a 1-9 twist help stabilize heavier bullets? What's the heaviest bullet that will shoot accurately from my rifle?

kemassey · July 2, 2016, 09:11 AM

I think the 1/9 is good for 55gr. 1/7 twist will work better for heavier rounds. Others with more experience will be along soon.

Sent from my two story out house.

SRH78 · July 2, 2016, 09:25 AM

It varies some but typically 1:9 is good for 69 grains. It is 1:12 that is typically good for 55 grains. Of course, it is the actual length of the bullet rather than the weight that matters.

jersurf101 · July 2, 2016, 09:42 AM

My 1/9 16" has been good with projectiles up to 68 grains although I have not tried any heavier

Mobuck · July 2, 2016, 10:01 AM

You can likely get decent accuracy with slightly heavier bullets (due to the 24" barrel) than might be had with the same twist in 16". Bullet stability is a factor of both twist and bullet speed.
I have a 1-9 20" AR that does quite well with 69 HPBT.

COSteve · July 2, 2016, 10:04 AM

Some 1:9 twist barrels will stabilize up to 75grn bullets, however, that isn't a given. 68/69grn are the max that you can assume it will stabilize. My Wylde chambered RRA A4 set up for semi-long range shooting (400yd+ apples

) runs 68grn Hornady's perfectly with TAC powder and Remington 7½ primers.

Knightsofnee · July 2, 2016, 12:30 PM

In a nutshell, you're going to have to buy a box of whatever it is you want to shoot and see if it works.

1tfl · July 2, 2016, 01:25 PM

Actually it's not the weight but the length of the bullet that matters.
It varies by individual rifle but in a longer length bolt rifles, 1-12 maxes out at 60gr flat base bullet. 1-9 usually max out at about 70gr and 1-8 can go up to about 75gr. 1-7 can go up to 85 gr. I have an older Remington 700 PPS with 1-12 twist that stabilizes Winchester 64gr Power Point out to 250 yards.

Theohazard · July 2, 2016, 06:08 PM

OP, your question is answered in this sticky at the top of the General Rifle forum:

.223/5.56 Twist Rate Information

Brutus · July 3, 2016, 08:34 AM

Great info, thanks

dean1818 · July 3, 2016, 09:37 AM

1-7 is my choice

The 556 is a "good enough" round for hunting within 100 yards, with the heavier bullets for Pigs and deer

The 1-9 doesnt stabilize these bigger bullets as well

Brutus · July 3, 2016, 03:36 PM

Well what I got is a 1-9 with a 24" barrel, bought it as a target rifle and my interest in the heavier bullets is for down range accuracy at 200+ yards.
223's are illegal to hunt big game with in my neck of the woods and I consider it a varmint round. My hunting choices start with the 30/30 and go up from there.

Cowboy_mo · July 3, 2016, 07:54 PM

[QUOTE]I have a Bushmaster V-match, will the 24" barrel with a 1-9 twist help stabilize heavier bullets? What's the heaviest bullet that will shoot accurately from my rifle? [QUOTE]

Brutus, welcome to TFL. Great information provided hear and I think I can point you to an answer you will like.

Quote:

http://thefiringline.com/forums/showthread.php?t=530927

It is a great article complete with charts and graphs of the various bullet weights and twist rates. It is what I studied and studied before buying my AR in 1:7 twist a few months back.

Enjoy the site and enjoy your rifle.

bfoosh006 · July 5, 2016, 04:35 PM

Bear in mind... not all twist rates are equal...

In other words some are slightly faster or slower then "marked".

And you will have to try the specific bullet to see if it is GTG.

From Berger Bullets webpage ....

http://www.bergerbullets.com/wp_supe...-in-my-barrel/

"How do I find out the twist in my barrel?

Posted October 15, 2012

The best place to start is with the barrel or rifle maker. Sometimes this information is not available. One method of finding the twist rate of your barrel is by using a cleaning rod.
a.Put a dry, loose fitting patch (so it doesn’t get stuck in your barrel) on a jag and put your rod into your barrel from either the muzzle end or the chamber end. (Note: When putting a rod into the muzzle end, be careful not to damage the crown/muzzle).
b.Move the rod back and forth to verify that the rod spins freely as the rifling turns the rod.
c.With the rod in the barrel, make a mark on the rod with a Sharpie at the point where the rod enters the muzzle or the action.
d.Near the handle of the rod place a piece of tape on the top of the rod. Push the rod into the barrel.
e.You will see the piece of tape travel one full revolution as the rifling turns the rod.
f.When the tape is back to the top make another mark with your Sharpie on the rod where the rod enters the muzzle or the action.
g.Pull the rod out of the barrel and measure the distance between the two Sharpie marks.

If the distance is 12 inches, you have a 1:12” twist barrel. If the distance is 8 inches, you have a 1:8” twist barrel, and so on. For best results, repeat this process two or three times. If you find the measurement is 9.2 inches or 9.8 inches, you can shoot any bullets that are recommended for a 1:10” twist. You may or may not be able to shoot bullets that are recommended for a 1:9” twist.

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

Gunslick · July 5, 2016, 05:55 PM

I like 14.5 in barrels with permanently attached muzzle brakes in a 1/7 twist. I have taken pigs and mule deer with my ar but only out to about 175 yards. I love the ar for hunting. I always go with the 1/7 twist because I have shot 53 gr. Vmax out to 200 with very good accuracy. That is just my opinion though.

July 2, 2016, 09:08 AM	#1
Brutus Senior Member Join Date: September 11, 2005 Posts: 1,023	5.56 twist rate I have a Bushmaster V-match, will the 24" barrel with a 1-9 twist help stabilize heavier bullets? What's the heaviest bullet that will shoot accurately from my rifle? __________________ Courage is what it takes to stand up and speak out, Courage is also what it takes to sit down and listen, Winston Churchill.

July 2, 2016, 09:25 AM	#3
SRH78 Senior Member Join Date: April 18, 2011 Location: Texas Posts: 517	It varies some but typically 1:9 is good for 69 grains. It is 1:12 that is typically good for 55 grains. Of course, it is the actual length of the bullet rather than the weight that matters. __________________ "Those who would give up essential liberty to purchase a little temporary safety, deserve neither liberty nor safety." - Benjamin Franklin

July 2, 2016, 06:08 PM	#9
Theohazard Senior Member Join Date: April 19, 2012 Location: Western PA Posts: 3,829	OP, your question is answered in this sticky at the top of the General Rifle forum: .223/5.56 Twist Rate Information __________________ 0331: "Accuracy by volume."

July 3, 2016, 08:34 AM	#10
Brutus Senior Member Join Date: September 11, 2005 Posts: 1,023	Great info, thanks __________________ Courage is what it takes to stand up and speak out, Courage is also what it takes to sit down and listen, Winston Churchill.

July 3, 2016, 09:37 AM	#11
dean1818 Senior Member Join Date: December 5, 2009 Location: Frisco Texas Posts: 844	1-7 is my choice The 556 is a "good enough" round for hunting within 100 yards, with the heavier bullets for Pigs and deer The 1-9 doesnt stabilize these bigger bullets as well __________________ An imperfect servant of my Lord and Saviour, Jesus Buying American made, wherever I still can

July 2, 2016, 09:11 AM	#2
kemassey Senior Member Join Date: October 18, 2009 Posts: 148	I think the 1/9 is good for 55gr. 1/7 twist will work better for heavier rounds. Others with more experience will be along soon. Sent from my two story out house.

July 2, 2016, 09:42 AM	#4
jersurf101 Senior Member Join Date: January 27, 2013 Location: Eastern NC Posts: 553	My 1/9 16" has been good with projectiles up to 68 grains although I have not tried any heavier

July 2, 2016, 10:01 AM	#5
Mobuck Junior member Join Date: February 2, 2010 Posts: 6,846	You can likely get decent accuracy with slightly heavier bullets (due to the 24" barrel) than might be had with the same twist in 16". Bullet stability is a factor of both twist and bullet speed. I have a 1-9 20" AR that does quite well with 69 HPBT.

July 2, 2016, 10:04 AM	#6
COSteve Senior Member Join Date: September 6, 2009 Posts: 1,344	Some 1:9 twist barrels will stabilize up to 75grn bullets, however, that isn't a given. 68/69grn are the max that you can assume it will stabilize. My Wylde chambered RRA A4 set up for semi-long range shooting (400yd+ apples ) runs 68grn Hornady's perfectly with TAC powder and Remington 7½ primers.

July 2, 2016, 12:30 PM	#7
Knightsofnee Senior Member Join Date: March 1, 2013 Posts: 150	In a nutshell, you're going to have to buy a box of whatever it is you want to shoot and see if it works.

July 2, 2016, 01:25 PM	#8
1tfl Senior Member Join Date: September 12, 2007 Posts: 287	Actually it's not the weight but the length of the bullet that matters. It varies by individual rifle but in a longer length bolt rifles, 1-12 maxes out at 60gr flat base bullet. 1-9 usually max out at about 70gr and 1-8 can go up to about 75gr. 1-7 can go up to 85 gr. I have an older Remington 700 PPS with 1-12 twist that stabilizes Winchester 64gr Power Point out to 250 yards.

July 3, 2016, 03:36 PM	#12
Brutus Senior Member Join Date: September 11, 2005 Posts: 1,023	Well what I got is a 1-9 with a 24" barrel, bought it as a target rifle and my interest in the heavier bullets is for down range accuracy at 200+ yards. 223's are illegal to hunt big game with in my neck of the woods and I consider it a varmint round. My hunting choices start with the 30/30 and go up from there. __________________ Courage is what it takes to stand up and speak out, Courage is also what it takes to sit down and listen, Winston Churchill.

July 5, 2016, 04:35 PM	#14
bfoosh006 Senior Member Join Date: February 17, 2009 Posts: 1,089	Bear in mind... not all twist rates are equal... In other words some are slightly faster or slower then "marked". And you will have to try the specific bullet to see if it is GTG. From Berger Bullets webpage .... http://www.bergerbullets.com/wp_supe...-in-my-barrel/ "How do I find out the twist in my barrel? Posted October 15, 2012 The best place to start is with the barrel or rifle maker. Sometimes this information is not available. One method of finding the twist rate of your barrel is by using a cleaning rod. a.Put a dry, loose fitting patch (so it doesn’t get stuck in your barrel) on a jag and put your rod into your barrel from either the muzzle end or the chamber end. (Note: When putting a rod into the muzzle end, be careful not to damage the crown/muzzle). b.Move the rod back and forth to verify that the rod spins freely as the rifling turns the rod. c.With the rod in the barrel, make a mark on the rod with a Sharpie at the point where the rod enters the muzzle or the action. d.Near the handle of the rod place a piece of tape on the top of the rod. Push the rod into the barrel. e.You will see the piece of tape travel one full revolution as the rifling turns the rod. f.When the tape is back to the top make another mark with your Sharpie on the rod where the rod enters the muzzle or the action. g.Pull the rod out of the barrel and measure the distance between the two Sharpie marks. If the distance is 12 inches, you have a 1:12” twist barrel. If the distance is 8 inches, you have a 1:8” twist barrel, and so on. For best results, repeat this process two or three times. If you find the measurement is 9.2 inches or 9.8 inches, you can shoot any bullets that are recommended for a 1:10” twist. You may or may not be able to shoot bullets that are recommended for a 1:9” twist. https://www.youtube.com/watch?v=cdoCNZBlRGQ

July 5, 2016, 05:55 PM	#15
Gunslick Senior Member Join Date: July 3, 2016 Posts: 321	I like 14.5 in barrels with permanently attached muzzle brakes in a 1/7 twist. I have taken pigs and mule deer with my ar but only out to about 175 yards. I love the ar for hunting. I always go with the 1/7 twist because I have shot 53 gr. Vmax out to 200 with very good accuracy. That is just my opinion though.