Thread: How to get fast twist barrels in NZ

Im after a pair of barrels one in 338 cal and one in 30 cal

the trick is I want absurdly fast twist rates (1-5 for the 30 and 1-3 for the 338)

or basically as fast as possible as I can get my hands on.

Pacnor was awesome for doing this but they have recently had a fire

trueflights 1-8 premium suppressor is about as fast as I have found locally but before I go with that i'm keen to see if there's anything Iv missed

Why? they are both for subsonic rifles, and faster twist rates deliver more energy and stability with the bullets I want to use

Originally Posted by Bill999

Im after a pair of barrels one in 338 cal and one in 30 cal

the trick is I want absurdly fast twist rates (1-5 for the 30 and 1-3 for the 338)

or basically as fast as possible as I can get my hands on.

Pacnor was awesome for doing this but they have recently had a fire

trueflights 1-8 premium suppressor is about as fast as I have found locally but before I go with that i'm keen to see if there's anything Iv missed

Why? they are both for subsonic rifles, and faster twist rates deliver more energy and stability with the bullets I want to use

What are these projectiles? Do, pray tell

@Bill999
Sound silly
I like silly projects because you learn things you didn't know

I have a mate who makes barrels commercially and has the barrel drills for what you want.
I just know he won't have the rifling buttons that fast because he's tapped out at 1:7 on the 30

But he might be able to get much faster buttons.
How much faster i don't know
But he will be visiting me today or tomorrow for a toy swap around and i can mention it to him

You're welcome to pm me and we can make direct contact and i can fill you in on who and what and where

@Bill999 , it looks like you watched that video about the 338 creedmoor or something like that.
I am not convinced that Going super fast twist in 338 will bring any real benefits as they pretend in that video.
We will see how it works for you once you build that rifle. Good luck with the project.

Originally Posted by akaroa1

@Bill999
Sound silly
I like silly projects because you learn things you didn't know

I have a mate who makes barrels commercially and has the barrel drills for what you want.
I just know he won't have the rifling buttons that fast because he's tapped out at 1:7 on the 30

But he might be able to get much faster buttons.
How much faster i don't know
But he will be visiting me today or tomorrow for a toy swap around and i can mention it to him

You're welcome to pm me and we can make direct contact and i can fill you in on who and what and where

I did have a chat over email to that chap about 338 barrels and with current tooling 1-9 is as fast as he has currently because that's what's in demand, Iv recently picked up another rifle to do a 300 black out with so i am going to concentrate on that till more info on 8.6 creed comes out in the next few months
The guy from Vulcan was a top bloke I would be keen to hear what he can do in a fast twist 30cal

Originally Posted by Bill999

I did have a chat over email to that chap about 338 barrels and with current tooling 1-9 is as fast as he has currently because that's what's in demand, Iv recently picked up another rifle to do a 300 black out with so i am going to concentrate on that till more info on 8.6 creed comes out in the next few months
The guy from Vulcan was a top bloke I would be keen to hear what he can do in a fast twist 30cal

Vulcan 1:8 30 1:9 338

Originally Posted by Moa Hunter

What are these projectiles? Do, pray tell

Perigrine and Lehigh subsonic expanders

Originally Posted by Friwi

@Bill999 , it looks like you watched that video about the 338 creedmoor or something like that.
I am not convinced that Going super fast twist in 338 will bring any real benefits as they pretend in that video.
We will see how it works for you once you build that rifle. Good luck with the project.

I'm keen to give it a shot, things I will need arnt really available yet around the 8.6creed so I'm going to put that on the back burner and give more information a chance to come out.
Apparently the 1-5 twist barrels in ar15 blackout pistol length barrels work really well. I'm looking at a 11 inch barrel (breachface to barrel end) and slower twists are ok in longer barrels where there is more time in the barrel for the bullet to stabilise. I'm fitting in somewhere between these two with short but not super short.
At this stage my plan is to send it to trueflight and get ask them to fit a premium suppressor 1-8, unless I can find something a little quicker twist

Surely twist is twist
Longer barrel shouldn't make a difference to the bullet twist just the speed

Its not like they slip and then grip and twist
They grip and twist all the way as they accelerate ( surely)

Speed will be set at about 1000fps so all I'm hoping for is accuracy

Ive done a lot of work with sub loads in these cartridges over the years and I cant see any advantage of going to such fast twist barrels for them.. in fact I think you will find they will actually add more issues than advantages such as higher case pressures and wobbly over stabilised bullets.
Hornady is just trying to baffle us with the marketing BS one again.

A history lesson for you may better explain. Back when the late J D Jones thunk up the Whisper idea his intentions were to use the heaviest bullets with the highest BC's in a cartridge just big enough to shoot in the subsonic realm in a fast twist barrel that could stabilise such a bullet at low speeds.
For reference I will only speak of the .300 Whisper and the .338 whisper as this is what you have shown interest in.
JD used Shilen to make custom barrels for him for this venture and his twist rate was 1-8" for both the .300 and the .338 cartridges.
At the time the heaviest bullets available for these two were the Wildcat bullets which were 250gr in .308 and 350gr in .338 which were perfectly stable to 1000 yards with a 1050fps muzzle velocity in these 1-8" twist custom barrels.





Later due to more commercial availability they advised and used the Sierra match king 240gr in .308 and 300gr in .338, both of which were also perfectly stable at sub velocities out to 1000 yards. Why? because that's the twist rate JD settled on after a LOT of testing with custom Shilen barrels.

Fast forward to modern day... enter military contracts and the need for the .300 whisper to be Saami spec, out it rolls with a brand new name... .300 Blackout. This also brought popularity and more availability to components for both rifles and ammunition. While JD discovered that the 1-8" twist was by far the most accurate twist for the .300 Whisper with the 240 and 250gr .308 bullets, the trend was for the shorter AR15s to go to a 1-7" twist and a lighter 180gr to 220gr bullet at sub speeds. You guessed it... The shot like crap compared to the heavies through the 1-8" Shilens... but the single ragged hole subsonic groups had long been forgotten with the requirement for military units to only perform to MOA at 100y.

The crazy thing in all this marketing hype is actually the fact that now we have all these lighter weight special expanding subsonic well balanced bullets the twist rates should actually be getting slower not faster.
Take the new Hornady 190gr SubX bullet for example, it is stable at sub velocities out of a 1-10" twist.

The .338 350gr Wildcat bullet was stable in the 1-8" Shilen barrel but not in the Trueflight 1-9 barrel. The 1-9" truflight only just stabilises the 300gr SMK and not the 300gr Berger VLD at sub speeds so a 1-8" is the best for the .338 for the longest bullets in its class. once again the new expanding sub bullets in .338 are lighter and shorter so a 1-9" or even 1-10" will work fine.
Here is the Berger VLD (Left) and SMK (right) side by side, not a big difference which suggests the 1-9" is borderline to slow for these 300gr heavies at sub speeds:



While it seems Hornady is doing ground breaking stuff... they are just to re-invent the wheel, it has all been done before only on a lesser marketing budget.
8.6 Creedmoor is nothing more than the .338 Whisper which is a 6BR or 7BR cartridge necked up to .338.
once Remington stopped making 7BR brass I started to make my own using stronger Lapua SRP .308 Palma brass in the same fashion you can make .300 whisper/BLK brass from .223Rem brass.





Here are a couple of links to threads Ive started previously dedicated to this topic if you are interested:

https://www.nzhuntingandshooting.co....-300blk-44679/

https://www.nzhuntingandshooting.co....-300blk-44692/

Personally I think if I was to build another subsonic rifle Id lean toward one of @Kiwi Gregs 8.6x47 Lapua's.
Much better brass and the flexibility to load viable high velocity lighter bullet loads for longer shots if needed.
Not sure if the 1-8" .338 Shilen barrels are still available but that would be my first choice, or a 1-9" true flight would be fine in that.
Do you have the chamber reamer for that one Greg or was it just a 6.5x47 lap followed up with a .338 N&T reamer?
I considered a 6mm Norma Dasher necked to .338 with its slightly longer brass and 40 deg shoulder compared to the shorter the 6BR with the 30deg but I think this 8.6x47 Lap will make the most of a short action and multi purpose loadings.

Originally Posted by Wingman

Personally I think if I was to build another subsonic rifle Id lean toward one of @Kiwi Gregs 8.6x47 Lapua's.
Much better brass and the flexibility to load viable high velocity lighter bullet loads for longer shots if needed.
Not sure if the 1-8" .338 Shilen barrels are still available but that would be my first choice, or a 1-9" true flight would be fine in that.
Do you have the chamber reamer for that one Greg or was it just a 6.5x47 lap followed up with a .338 N&T reamer?
I considered a 6mm Norma Dasher necked to .338 with its slightly longer brass and 40 deg shoulder compared to the shorter the 6BR with the 30deg but I think this 8.6x47 Lap will make the most of a short action and multi purpose loadings.

When we made my 338 BRX AR15 upper we cocked up & used 338 Whisper reamer which meant the throat was too long for the projectiles I wanted to run & they were crap

The 160 TTSX on the other hand went fantastic, 1/2 to 3/4 moa was easily achievable at 25-2600 fps with a 20" barrel, it was an awesome upper on a 1-9 True-Flite barrel

I wanted more case capacity for its replacement only having a 11.75" barrel to get 2600 fps & still easily keep it in a magazine.

We used a 6.5 x 47 Lapua & 338 Federal reamer to make the chamber

Thanks for these responses guys it's cool to hear what people with previous experience have found to be successful.
Ruger 300blk Americans stack hornady sub x from what I have seen out of my friends with their 1-7 barrels
I would really like the opportunity to buy off the shelf top quality sub rounds like sub-x if it's just picking a case out of a hat as things seem to be between the 223 and 308 case size in all of these sub rounds. Purely for convineience and availability, I'm not interested in case forming

FWIW the Bergara B 13 takedown 308 is 1:8” twist...16” barrel.