Ideal twist rate for shooting 77 gr. bullets ?

[RidgeRunner]

I plan to put another AR15 rifle together that would be good for shooting the Nosler 77 gr. Custom Competition bullets. What is the ideal twist rate for a barrel chambered in .223Rem to shoot the Nosler 77 gr. Custom Competition bullets?

 

[remingtonman_25_06]

I bet a 1 in 8" would work nicely...

 

[Asa Yam]

Anything faster than 1-9".

Unlike most people, I don't subscribe to the theory of "twist rate giving the best accuracy for a given weight bullet". In ballistics, "stable" means the ability of the projectile to return to point first flight following application of an external force. Using this definition, any twist rate that fails to return the bullet to point first flight is bad. However, a stable bullet will still pitch and yaw in flight.

"Excessive twist" is far better than "not enough". When you get to "not enough" groups open up radically. Groups of 12" at 100 yards (not a typo) have been recorded in such instances.

 

[MNsportsman60]

Don't want to hijack Ridgerunners thread but have a question, generally speaking is it better to have a faster twist rate for a heavier bullet (based on cal.) or a slower rate?

Example I have a Win Model 70 in 3006. What twist rate would you use for a 165 AB vs a 200 AB? I realize that manufacturers turn out barrels that are a compromize for a given cal, but does the "factory twist" have the ability to stabilize heavey bullets for cal.

Thanks in advance for any reply's

Steve

 

[Guy Miner]

A longer, heavier bullet will require a faster twist rate to stabilize it.

Factory .30-06 rifles handle 200 gr bullets just fine. :grin:

 

[nomosendero]

My RRA Varmiter REALLY likes the 77MK!!

 

[Alaska]

1:8" or 1:7" for 77/75gr in 20" AR 15

Heard the 75 AMAX is kicking butt!


68/69 the 1:9" twist.

 

[6ppcar]

Don't want to hijack Ridgerunners thread but have a question, generally speaking is it better to have a faster twist rate for a heavier bullet (based on cal.) or a slower rate?

Example I have a Win Model 70 in 3006. What twist rate would you use for a 165 AB vs a 200 AB? I realize that manufacturers turn out barrels that are a compromize for a given cal, but does the "factory twist" have the ability to stabilize heavey bullets for cal.

Thanks in advance for any reply's

Steve

\

1-10 twist

 

[JD338]

1:10 twist for the .308 cal and 1:8 twist for the .224 cal 75/77 gr bullets.

JD338

 

[Antelope_Sniper]

Most Factory rifles are rifled to stabilize the heaviest bullets most shooters would reasonably shoot in a given cartridge, i.e. 160's in a .270, 175 in a 7mm mag, 200-220 in a 30.06, 275 in a 338 Win Mag.

The advantange of a faster twist, is you can stabalize a wider range of bullets. I have a Mosin Nagant with a realitivly slow twisting barrel. It shoots 150gr bullets fine, but 180gr bullets "keyhole" They actually hit the paper SIDEWAYS at 25 yards. :?

However, the faster the twist, the more stress places on the bullet and barrel. My dad's old 30.06 is rifled to handle 220 grain bullets. Sometimes the 100gr Hornadies will actually come apart in flight before reaching the target. Kind of looks like a bad shotgun patterns.

For these reasons, may of your target shooting building customer guns will opt for the slowest twist reasonable for the bullet weight they intend to shoot. This provides the least stress on the bullet and barrel, and the most consistency from shot to shot. It's not uncommon for your heavy varmit benchrest shooters to us 1/14 or even 1/15 twist barrels for their 52gr match bullets out of their .224 barrels.

In general for a .223, the standard factory twist of 1/10 is fine for up to 60 gr bullets.
1/9 is considered "ideal" for 62 gr bullets, and will stabalize up to a 69 gr bullets.
1/8 for 77-80 grain bullets
1/7 for the obserdly heavy stuff in the 90-100 grain range.

These are just guidelines. In reality the bullets LENGTH is more important then it's weight, and bullets do not stabalize as well in cold weather. Typically, 55 gr bullets out of a 1/14 twist AR barrel will not stabalize in artic conditions.

 

[SJB358]

In our M4's our rifles have a 1-7 twist in order to stabilize the 77gr bullets. They seem to shoot really well. Not sure about match guns though, but I would think it should still apply to some extent. Scotty

 

[FOTIS]

1:7

 

[GB300wm]

My m4 has 1 : 7" twist rate especially for the 77 grainers. I would bet the military has done their homework on this. My vote goes for the 7 twist. :grin: :grin:

 

[Nomad]

Have a 1/8 twist in AR and shoot the 52gr Amax to the 75 gr Amax and have no problems,
including 60gr, lots of 55gr, and 69gr ....
Powders range from H335 on the light to varget and RL-15 on the heavier.....