cart SHOPPING CART You have 0 items
SELECT CURRENCY

Discussion Forums

Search forums
Forum Index > Rifles general discussion > two twist rates one barrel????

two twist rates one barrel????

25 Feb 2016
@ 07:46 pm (GMT)

Sebastian Shand

i was yarning to a gunsmith the other day who was saying somebody (can't remember the name) is making barrels that start off with a slow twist and ends with a tighter twist rate?
I'm trying to figure out if this has any advantages or weather its just anew fad to make extra coin out of gullible tacticool wanna be snipers.

I'm slightly dubious at this point but yeah anybody have more details on this?
google isn't being very forthcoming on the subject...

Replies

25 Feb 2016
@ 08:42 pm (GMT)

Warwick Marflitt

Re: two twist rates one barrel????
Id thought about the idea of it. I guess the approach is to increase the spinning gradually as the projectile travels and increases in velocity. With a set twist rate the bullet gets slammed into the lands the bullet is twisted and forced forward accelerating in two directions at the same time putting lots of stress into the bullet.
Watch a Topfuel Dragster as 7,000 hp and thousand of ft lbs of torque are unleashed into the chassis! It twists and flexes violently. Do the maths and work out the acceleration g-forces on a bullet? I guess someone has to explore and experiment? The first man who threw a stone never dreamed that one day man would throw things into space!!!! Lets see what comes out of it? As an aside. Look at the US Navy's " Rail guns". No gunpowder it uses electromagnetic coils to throw a projectile at insane speeds and distance! !!!
I must say that "Variable twist rate" does have a nice Commercially marketable sound to it...... anyone else got an opinion or know more about it. ?
25 Feb 2016
@ 09:25 pm (GMT)

Thomas Kitchen

Re: two twist rates one barrel????
There's been gradual twist rates for year steaming from the cast projectiles days. I believe the Italian carcano was one of the last rifles designed for jacketed bullets that uses this system. I know people discovered issue when shortening the barrels thou as it chages twist rate. Be interesting to see what would happen if you were at final twist rate by half way down the barrel. At a guess better velocity but not sure if bullet would stabilize quick enough for the accuracy
25 Feb 2016
@ 09:56 pm (GMT)

Sebastian Shand

Re: two twist rates one barrel????
this concept may work well for target shooters where barrel length is no problem maybe? it does sound good but it'd be good to see some science behind it.

Warwick, those rail guns blow my mind and i cannot wait for the concept to be dropped into a hunting rifle, altho reloading ammunition is part of the fun.
imagine the day when reloading brass cases will be the same as using muzzle loaders in todays world....
26 Feb 2016
@ 01:31 am (GMT)

Bryan Webster

Re: two twist rates one barrel????
Check that out at Snipershide.com
I think it is a barrel made by Bartlein called a progressive twist barrel.
26 Feb 2016
@ 02:17 am (GMT)

Warwick Marflitt

Re: two twist rates one barrel????
THREAD HIJACK sorry guys.
The recoil will be horrendous. I am only using my own thoughts to analysis this and may be totally wrong! My thoughts are that as powder burns the pressure builds and recoil builds progressively. Similar to the hp torque curve of a petrol engine as rpm increases.. An electric motor makes maximum torque at zero rpm. So the rail gun will smash hard as it reacts to the input of energy. Then again its probably possible that it would fire a 10 grain bullet at 7,000 fps. Put that into quick load for the ft lbs it makes? You will need tungsten cored pre grooved and lubed projectiles. The rail gun(Electro magnetic cannon) videos are quite incredible to watch

https://m.youtube.com/watch?v=9PItPL7EZEc
26 Feb 2016
@ 03:04 am (GMT)

Nathan Foster

Re: two twist rates one barrel????
Nothing wrong with gain twist bores. I believe that besides Bartlein, there is one guy cutting these in Canada still (BC?). My late friend and forum member AJ had one in .308 Norma from memory, was a tack driver.

Put it this way, if people had the option of adopting gain twists rather than opting for (or being influenced by marketing of) super fast twists in their magnums (7mm 1:8 etc), folk like Berger would not have had to toughen their bullets.

It is like you said Warwick, much kinder on the projectile than instant max RPM.

I suspect however that it may be harder to get right in manufacturing and as has been said, barrel length becomes an issue.
26 Feb 2016
@ 04:34 am (GMT)

Bryan Webster

Re: two twist rates one barrel????
Here is the link to a youtube video of thie Bartlein gain twist bbl

http://youtu.be/pgT6E098Uqk
26 Feb 2016
@ 11:24 pm (GMT)

Sebastian Shand

Re: two twist rates one barrel????
very interesting indeed, i don't know why I've never heard of it before seeing as its been around for so long.

going by the man in the youtube clip it helps prevent the projectile skidding on the lands which makes sense
. i also found his point interesting about right and left hand twists for right and left hand shooters.

i might have to look into one of these barrels for a future build i think as curiosity is luring me into the trap.
27 Feb 2016
@ 03:21 pm (GMT)

Bryan Webster

Re: two twist rates one barrel????
That fellow can really shoot. Those shots were 500 yards and those at the end of the clip grouped well if you noted that.
27 Feb 2016
@ 07:39 pm (GMT)

Chris Murphy

Re: two twist rates one barrel????
Well i don't go too much on his sales pitch for left twist for right shooter cos if you hold the rifle properly every time the bullet will go where it went when you zeroed it. he then goes into spin drift and how having a left twist will cancel out Coriolis but then he's spinning it at 7.75. faster you spin it the more drift you get and its only going to cancel out one direction and that barrel is starting fast anyway with 8.25
the theory is there but he aint selling it right.
maybe he needs a little wind sock on the end of his barrel so he know the wind direction as well
27 Feb 2016
@ 07:58 pm (GMT)

Nathan Foster

Re: two twist rates one barrel????
Well thats just not on. Steph tells you about her "Tactical corner" channel for youtube and all of the wonderful products she is going to create, and you just had to let the cat out of the bag. The barrel mounted wind sock was her masterpiece.

Next you'll be telling people about her tactical awning.

I was going to bring back the SLR carry handle as a tactical toilet roll holder.

I still think there is room for the picatinny rail mounted picatinny rail.

Good points Chris.
27 Feb 2016
@ 08:25 pm (GMT)

Chris Murphy

Re: two twist rates one barrel????
its just un fair to keep such good product from the shooting community. now she has to start the "tactical corner" Patten pending of coarse dont want anyone else getting there first
28 Feb 2016
@ 12:19 am (GMT)

Warwick Marflitt

Re: two twist rates one barrel????
What about the straight twist barrel it will be fantastic for equatorial shots especially if you have east or west facing game animals! I'm thinking of developing the Safety Trigger?
You pull the trigger and an annoying voice ( like the GPS) will loudly proclaim that shooting is dangerous! that you must have been trained and licensed by said authority. That lead is a known cause of cancer in the State of California! You shouldn't use fireharms under the influence of drugs and alcohol ( so I can use one but not both?)
Now the arms code will be recited with options in 4 languages ( push 1 for French 2 for Dutch.......) finally you will hear." Are you sure you want to destroy the life of a sentient being "? Please release trigger wait 10 seconds and if you accept the responsibility for taking the life of the target and you have positively identified That it's not a person carrying a dead one ? Pull the trigger and wait 5 seconds. A siren will sound and then your rifle will fire! And then the arse covering legal disclaimer will follow!
YOU PULL THE TRIGGER 1,2,3,4,5 Siren Siren Siren BOOM!

YES ;D The SAFETY TRIGGER patent pending (c)
28 Feb 2016
@ 12:22 am (GMT)

Sebastian Shand

Re: two twist rates one barrel????
Yeap theory is always awesome until someone tests it out. I think his shooting technique works great with the rifle he's shooting but I have a funny suspicion if you put a 375 ultra mag un braked in his hands those groups may open up slightly.....

Nathan how could you and steph keep such fantastic products from the public!!? That's just not on.
[b]
28 Feb 2016
@ 03:31 am (GMT)

Bryan Webster

Re: two twist rates one barrel????
Yes, one can always work around the issues as in his video on the Bartlett gain twist barrels, but in any event I was responding to an info request from Sebastian.
28 Feb 2016
@ 04:38 am (GMT)

Thomas Kitchen

Re: two twist rates one barrel????
i wonder if Steph has a patent on a matte black painted wheelbarrow with a picatinny rail attachment so we can get our 338 lapua magnums around the tactobarrow? hogue could do aftermarket grips for it to.

warwick have a look at those tracking point scopes its not far off your idea
 

ABOUT US

We are a small, family run business, based out of Taranaki, New Zealand, who specialize in cartridge research and testing, and rifle accurizing.

store