Which barrel twist for an AR

[LONG RANGE CAPT]

Been toying with getting an AR for CSR and see that many rifles have 1:8 twist barrels, yet with the amount of RG ammo available would having a 1:7 twist be a wiser choice ?

As the 1:7 configuration would replicate the barrel carricteristics of the SA80 which from my experience is accurate.

[Aggy]

Both mine are 1.8

[John MH]

If I had a choice I'd get 1 in 7 over 1 in 8 although both will stabilise milsurp 62 grain bullets and heavier 77s.

 

All mine are 1 in 7 twist apart from one barrel from Armalon that is 1 in 200mm.

[Brillo]

I had a 1 in 8 twist 29" barrel .223 and it stabilised Berger 80 grainers nicely.

[bradders]

I find it doesn't make much difference as long as it's a good barrel,

[Shuggy]

The 1 in 7 twist was designed to stabilise the pencil-like L110 pattern tracer rounds in Arctic conditions. It's not necessary for the SS109 ball rounds which are fine with 1 in 8 or 1 in 9.

[gbal]

The 1 in 7 twist was designed to stabilise the pencil-like L110 pattern tracer rounds in Arctic conditions. It's not necessary for the SS109 ball rounds which are fine with 1 in 8 or 1 in 9.

I should not think much L110 would be fired in CSR.

Is not the real issue,just what bullets will be fired.

Mention was made of surplus RG,but it may not always be available or frankly very good-it is a limitation in some ways.

Bradders point that a good barrel matters is relevant too.

 

I can't see much advantage in a 1 in 9,and would go for 1 in 8,(or 1 in 7,if very heavy bullets are to be the norm).Accuracy or lack of in SA80 probably has little directly to do with twist rate in an AR clone.

Gbal

[John MH]

L85A2 accuracy is superior to the M16A2, in all the International Matches I've been to the L85A2 has generally beaten the best of the rest, usually in the hands of the British Army CST.

[gbal]

L85A2 accuracy is superior to the M16A2, in all the International Matches I've been to the L85A2 has generally beaten the best of the rest, usually in the hands of the British Army CST.

OK,just for the sake of it,let's agree the british army and its equipment is the world's best.

I am no expert,nor am I biased,nor a 'my country right or wrong' advocate,but does not AR suggest a non british weapon,and CSR

civilian use? Is the british service weapon actually available to civilians?Could David Tubb win with it? Does man-op make a difference;is the Aug a contender in semi auto?All interesting questions,BUT:-

 

To get back to the question asked,it was about the optimum twist for an AR ,so 1in 7,or 1 in 8 etc as JH has said,is what the answer should look like.Bullet weight,not nationality,is pertinent.I don't think CSR is limited to superior military ammo,but I might be mistaken.

If I am,then a relevant queston is,what ammunition,issue or home loaded,or commercial etc,,is actually the 'best',which will be something like 'most accurate' in this context,as we are not deploying in combat.

 

That answered,can we get onto the others?

Gbal

 

 

 

 

 

 

 

(I am no expert,nor country right or wrong fan,,but does not AR suggest a non british weapon (sort of AR/cloneand 'C refer to civilian?)

[John MH]

Rambling?

 

L85A2 Twist rate is the same as M16A2. As has already been said 1 in 7, 1 in 8 or 1 in 200mm all be fine, 1 in 9 will stabilise SS109 Milsurp but will start to struggle with heavier bullets such as the 77 and will really struggle with 80 grains should you ever want to shoot those. Therefore the 1 in 7 or 1 in 8 is the way to go.

[gbal]

Rambling?

 

L85A2 Twist rate is the same as M16A2. As has already been said 1 in 7, 1 in 8 or 1 in 200mm all be fine, 1 in 9 will stabilise SS109 Milsurp but will start to struggle with heavier bullets such as the 77 and will really struggle with 80 grains should you ever want to shoot those. Therefore the 1 in 7 or 1 in 8 is the way to go.

Sorry John,I did not mean 'rambling'-rather ,that these are more interesting other questions,once the twist issue is clear,and I did acknowledge you had commented clearly on that. The accuracy of specific military designs is almost certainly separate from the twist issue,but your conclusions are exactly as found in a wide variety of factory and custom barrels and designs,wrt stability and precision.Many such rifles have very high levels of accuracy too,'accurately' measured ,too.But that isn't just a twist issue,of course.

I would be really interested in your obviously informed views on some of the wider 'rambles' ,if you will.

Most civilians in the UK have no opportunity to seriously try mil spec gear,and comparative data is rather sparse-eg are there any 'across the course' type international competitions-the sort of point behind my reference to David Tubb,who doesn't use an Aug,eg!

I wish I could be as nifty cross receiver cocking it right handed as I see UK personnel seemingly doing left hand on their service weapon,admittedly not every shot,of course,but that is a mere detail.

Gbal

[John MH]

In my across the course AR built for High Power I have a White Oak Precision 20" HBar Profile Krieger 1in 7 Twist. It stabilises 77s and single fed 80s no problems at all.

 

My Tubb T2k in 6mm XC out shoots the AR only at greater than 600 yards.

 

David Tubb would probably shoot a L85A2 better then most of us.

[gbal]

In my across the course AR built for High Power I have a White Oak Precision 20" HBar Profile Krieger 1in 7 Twist. It stabilises 77s and single fed 80s no problems at all.

My Tubb T2k in 6mm XC out shoots the AR only at greater than 600 yards.

David Tubb would probably shoot a L85A2 better then most of us.

Great stuff ,John,thanks.Very informative.

I have no doubts at all about David Tubbs shooting,or yours.The interesting ramble might be,for either shooter,how would all the rifles mentioned rate against each other,( as in "the T2k outshoots the AR only beyond 600"),

and specifically how does the LA85A2 compare?

Most of us can't get them anyhow! All we can do is ask those more fortunate.

Gbal

[bradders]

Great stuff ,John,thanks.Very informative.

I have no doubts at all about David Tubbs shooting,or yours.The interesting ramble might be,for either shooter,how would all the rifles mentioned rate against each other,( as in "the T2k outshoots the AR only beyond 600"),

and specifically how does the LA85A2 compare?

Most of us can't get them anyhow! All we can do is ask those more fortunate.

Gbal

It's not about the type of rifle, it's about the type of shooting, hence Civilian Service Rifle Competitions.

This is as opposed to Military Service Rifle Competitions.

 

The fact that it is nigh on impossible to obtain a UK civvy legal L85/SA80 and fairly easy to acquire a UK civvy legal AR15 is somewhat irrelevant.

If we were allowed to have UK legal L85's then I'm sure the discipline would have evolved differently, and they would've been the Service class firearm.

As it is, that isn't the case and people are free to shoot whatever type if rifle they choose (as long as it meets the class rules)

As for the AR rifles, well I defy any of you to show me a better shooting machine.

60 years on and still getting better, none of the other rifles come close in any aspect.

 

That said, the AR15 (Armalite) type rifle is and has been British Military issue for many years and is even mentioned in the NRA's Bisley Bible

[SRJG]

Been toying with getting an AR for CSR and see that many rifles have 1:8 twist barrels, yet with the amount of RG ammo available would having a 1:7 twist be a wiser choice ?

As the 1:7 configuration would replicate the barrel carricteristics of the SA80 which from my experience is accurate.

 

First post on this forum guys.

As for the AR, I shoot a DPMS 20 inch 1-9 twist with 69g HPBT projectiles. I find that twist rate works well. I shoot this rifle in FTR sometimes (when i am not shooting my Barnard rifle), and at 500 yards it will shoot 50.5 on average on the ICFRA targets.

Using the 69 g means i can manufacture the ammo at mag length and almost get the jump i want, so i dont have to single load it. Friends of mine get similar results from 1-8 twist AR's

 

Steve