AR barrel twist

[OldGoat]

Hello, can someone give me a down and dirty explanation about AR barrel twist. I’m looking for a complete upper or build. I see there are common twist of 1-7 and 1-9. Is one better than the other?? Thx


ok, after a ten second search on the web, I found my answer, but feel free to throw something out there. Maybe personnal preference.

 

[sgreen3]

This page here will give a lot of good info regarding twist rate 223 Rem + 223 AI Cartridge Guide But a lot will depend upon what your planning to do with the rifle.

 

[OldGoat]

Thank you sgreen3 !!!

 

[cosermann]

See also here: ==>> :: Ammo Oracle

http://www.ar15.com/ammo/project/perf_twists.html

In a nutshell - faster twists will stabilize longer/heavier bullets, but may over-stabilize bullets on the light end, and may wear faster. 1:7 is the military twist. 1:9 is the most common commercial twist rate.

 

[gregkl]

It's interesting how the more you read, the more differences you see in recommendations.

I recently read that the 1:7 twist is optimum for 77 gr bullets shooting over 400 yards and for 55-62 gr bullets shooting less than 400 yards.

This seems to contradict what at least one of the links is saying. According to the Accurate Shooter link, a 1:14 or a 1:12 is best for the lighter rounds and at tops a 1:9 for a 73 gr bullet.

What's a man to do?

 

[sgreen3]

It's interesting how the more you read, the more differences you see in recommendations.

I recently read that the 1:7 twist is optimum for 77 gr bullets shooting over 400 yards and for 55-62 gr bullets shooting less than 400 yards.

This seems to contradict what at least one of the links is saying. According to the Accurate Shooter link, a 1:14 or a 1:12 is best for the lighter rounds and at tops a 1:9 for a 73 gr bullet.

What's a man to do?

Try a bunch of different stuff an just see how it shoots. Most of this stuff is just a guide. Pick a bullet you like an let the load development begin. If it doesn't give you the results you want, try something else.

 

[gregkl]

Try a bunch of different stuff an just see how it shoots. Most of this stuff is just a guide. Pick a bullet you like an let the load development begin. If it doesn't give you the results you want, try something else.

I can see that. I am planning on building an AR and I don't want buy a certain twist only to find out it was a poor decision.

I am looking at a SS 18" 1:7 Wylde barrel made by White Oak. It's not cheap so I don't want to lay out the cash only to find out a PSA complete upper for $300 would do just as well.

 

[sgreen3]

I have build a few ARs for bench type shooting one was for myself an the other was for a close friend of mine. The one I built for myself I used a 1:8 twist 223 Wylde chamber, their a little hard to find from what Ive seen but I liked it real well. The other for my firend was a standard 1:9. Mine with the 1:8 shot the 75gr stuff very well and also did as well with the 69gr stuff. Probably the same if you want to know the truth. Now his on the other hand would not shoot the 75gr stuff that good at all but once I loaded up some 69gr stuff for it, it shot just as well as the my gun and I had way more $ in it! I plan on doing another bench style AR for myself, an honestly I'm just going to get a regular 1:9 twist barrel. With proper load development there is not much that high end gun I had would do vs his gun. The real key is getting the load tailored to YOUR gun. That WOA barrel you talk about is a fine piece no question, I like the idea of the Wylde chamber, but me personally I don't see the benefit worth the cost. Or at least I didn't see it after it was said in done after comparing our two guns. In other words the key info in this post is LOAD DEVELOPMENT for you gun!

 

[cosermann]

... Is one better than the other?? ....

Better for what purpose?
How do you intend to use the rifle?
What loads do you want to shoot?

 

[xring62]

Get a 1-8" barrel,its a good compromise ,'heavy 'barrel ' too ,more weight helps by being easier to hold steady on target, cryogenetic treat it so it will not change zero as heated with firing.

 

[tradertator]

I prefer a chrome lined 1/7 over anything else. The chrome lining will really help extend the life of the barrel, especially when it gets hot. 1/7 can handle 55gr, as well as the heavy stuff. 1/9 is much more suited for 55gr and down.

 

[j706]

Get a 1/7 twist barrel. DO NOT buy into this jazz about a 1/7 not shooting lighter weight bullets. With my current Douglass barreled SPR precision AR it shoots 77 down to 40 grain just the same. When using my duty loads of 40,55 or 75 grain TAP there is zero difference in group size and minimal difference on POI with the same POA.

 

[gregkl]

Better for what purpose?
How do you intend to use the rifle?
What loads do you want to shoot?

These are important considerations in my opinion. Especially on the intended use. 3-Gun? Bench shooting? Long distance? Plinking? Varmint hunting? SD? Or maybe just an all around use.

Get a 1-8" barrel,its a good compromise ,'heavy 'barrel ' too ,more weight helps by being easier to hold steady on target, cryogenetic treat it so it will not change zero as heated with firing.

I think compromise is okay if you are looking for a all around rifle, but what if you want a tack driver?

I prefer a chrome lined 1/7 over anything else. The chrome lining will really help extend the life of the barrel, especially when it gets hot. 1/7 can handle 55gr, as well as the heavy stuff. 1/9 is much more suited for 55gr and down.

I have heard this but isn't chrome lining more of a benefit to military use or for someone who uses it often in inclement weather with infrequent cleaning? If you are a fair weather shooter and clean after each session, does chrome lining add any benefit? Also, it has been said that the CL barrels may reduce accuracy some. Is this true?

 

[MadTownGunny]

I have a 16" 1/7. Love it. I do better with it than I do my 20" 1/9. I shoot mostly 64g

 

[Niles Coyote]

My experience with 223/5.56 barrel twists in AR platforms and bolt rifles... A 1:9 twist will shoot well with 45-69 weight bullets and may shoot 75 & 77 also but not necessarily guaranteed. While 1:7 twists will shoot 60-80 grain bullets well and some lighter bullets handle the over-stabilization better than others. I have had zero luck reloading 55 Hornady FMJ’s and 55 Hornady soft points, that is, obtaining groups under MOA.

 

[karl77]

there is a correlation between twist rate and barrel length.

I have a 20" 1 in 8 barrel that pattens 62gr and below (5-6 inch groups), but shoots sub moa with 75gr. (electronrider has currently borrowed it for match shooting and can verify), while my 16" carbine with 1 in 9 likes 55-62 gr, and my buddy's 16" 1 in 7 likes 62-69gr.

 

[melensdad]

I'll leave this out here, its from experts in accurate shooting. I've said this many times, got tired of being told I'm wrong, so I'll let these experts say it and you can decide: 223 Rem + 223 AI Cartridge Guide

 

[tradertator]

I have heard this but isn't chrome lining more of a benefit to military use or for someone who uses it often in inclement weather with infrequent cleaning? If you are a fair weather shooter and clean after each session, does chrome lining add any benefit? Also, it has been said that the CL barrels may reduce accuracy some. Is this true?

Chrome lining isn't as big of a deal on lower velocity stuff like handgun cartridges, but is a real asset on higher speed rifle rounds. Where you'll see the biggest benefit is with erosion in the throat of the barrel.

The argument about accuracy is that the chrome could be applied unevenly and affect the lands & grooves in the barrel. From my experience, this hasn't been the case/ AR's are accurate but rarely used as precision weapons. Your not going to see a difference if your plinking or shooting a few hundred yards and the benefits far out weigh the cons.

 

[avboiler11]

A 1:9 will shoot 75/77 HPBT bullets just fine. They will be less stable than 1:8 or 1:7 barrels, and a lower velocity via shorter barrel will reduce that stability further...but sub-MOA with a tailored load should be possible.

However, those are not optimal weights.

My Precision AR is 1:8, and hammers with 77gr Nosler CCs.

 

[Ketchup]

1:7 twist like them heavy bullets. But yes, load development for your gun if you reload. 1:9 shoots 55gr and less.

It really boils down to the distance you want to shoot. Heavier bullets will hold up better the farther out you go.