Bartline
Gain twist
- Thread starter jessej
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Jeff Heeg osoh
Well-Known Member
This barrel is still used today the only thing changed from the picture is we upgraded from the GS custom bullets to the Flatlines from Warner. As you can see it is not destroying the bullet that we retrieved.
Lothar Walther have gain twist barrel in 30 cal and 338 from 16"-10" twist rate in 26" barrel lenght.
I know they will made anything if you have money.
I know that that barrel have more speed than normal and they seem to be more accurate.
I know they will made anything if you have money.
I know that that barrel have more speed than normal and they seem to be more accurate.
No doubt, go to Bartlein barrels - https://www.bartleinbarrels.com/ - they are the preeminent researchers and developers of gain twist. You can custom order your twist, and there are several benchrest shooters at Bartlein HQ that have utilized gain twist. I ordered a Carbon Wrapped barrel from them for a 7mm SAUM build that I have yet to place onto the action...saving up for a Defiance...
akmtnhnt
Well-Known Member
As opposed to the straight as it sits the couple thousandths off the lands and over the course of that .020" or so goes to 8 twist?
Because you can't possibly increase the twist rate faster than how rifles normally have rifling.
Calvin45
Well-Known Member
That extreme of a progression in twist seems insane.
Do it! Let us know what happens.
Seriously though, one thing I've always been curious is polygonal rifling for a gain twist instead of lands and grooves. Seems to me that'd be waaaaaay less strain on the jacket/core union than conventional rifling. I've been curious about that possibility a long time. Gain twist and very slight gain choke/squeeze with polygonal rifling.
Also seems would be way less sensitive to throat erosion and easier to clean. But I figure there must be a reason no one is doing this. Either that or I'm a visionary with insufficient funds
Do it! Let us know what happens.
Seriously though, one thing I've always been curious is polygonal rifling for a gain twist instead of lands and grooves. Seems to me that'd be waaaaaay less strain on the jacket/core union than conventional rifling. I've been curious about that possibility a long time. Gain twist and very slight gain choke/squeeze with polygonal rifling.
Also seems would be way less sensitive to throat erosion and easier to clean. But I figure there must be a reason no one is doing this. Either that or I'm a visionary with insufficient funds
That's the way i feel!Either that or I'm a visionary with insufficient funds
I thought the same over the years and have wondered if it's ever been experimented with. In my mind, it would have less initial pressure spike and be much less damaging to thin jacketed, heavy for caliber bullets and effect burn rates. Good luck in finding someone to do it and please share your results if you do.
Actually it seems I read about the gain twist being used by the Germans in WWll. Pretty radical values also.
We have been working with Bartlein on non-standard gains - and to date for great success. Two major reason: first being initial pressure. Screw threads take force. The tighter the thread the greater the force to move an object down the thread. The other reason... maybe later. The minors are a goal of increased velocity, spread the initial pressure pulse over a longer distance, reducing pressure equals less temperature, longer throat life... to name a few.
We built a pair of .460's - identical except for the gain values. One was 1.5tgain the other a 4t gain. The gun with the 4t gain can runs +5gr grains less powder for +70fps on the same round with less felt recoil. Our 300WM runs 12-8 on the twist.. a bit more non-standard features are being added to that barrel and will shortly put rounds down that tube. Accuracy wise the .460's have documented 1.25" three shot groups at 600yds. Perhaps not 6mm territory but recoil control of a 6mm Dasher as compared to a .460 shooting a 635gr Badlands bullet at 3070fps...
We have been working with Bartlein on non-standard gains - and to date for great success. Two major reason: first being initial pressure. Screw threads take force. The tighter the thread the greater the force to move an object down the thread. The other reason... maybe later. The minors are a goal of increased velocity, spread the initial pressure pulse over a longer distance, reducing pressure equals less temperature, longer throat life... to name a few.
We built a pair of .460's - identical except for the gain values. One was 1.5tgain the other a 4t gain. The gun with the 4t gain can runs +5gr grains less powder for +70fps on the same round with less felt recoil. Our 300WM runs 12-8 on the twist.. a bit more non-standard features are being added to that barrel and will shortly put rounds down that tube. Accuracy wise the .460's have documented 1.25" three shot groups at 600yds. Perhaps not 6mm territory but recoil control of a 6mm Dasher as compared to a .460 shooting a 635gr Badlands bullet at 3070fps...
You must be the harmonics engineer mark told me about.
Hand Skills
Well-Known Member
Ron Smith out of Alberta Canada has been manufacturing gain twist barrels for at least 2 decades (probably more). See if you can get in touch with him before he retires. Ron is a wealth of information.
Constantly Evolving pressure seal??
That's where I imagine the velocity increase comes from.
Calvin45
Well-Known Member
Perhaps I might be that guy..LOL.
We are not only looking to reduce overall "whip", harmonics, etc... to reduce the time line of the event. I think we are getting somewhere as we have multiple shooters note that their barrels are flat out the most accurate barrels they have ever had- across a broad spectrum of loads.
Velocity- a constantly evolving pressure event will create a better seal .. arguments coming ... especially in a hostile environment. The other velocity comes from changing directions. When a barrel goes into a sinusoidal whip, the bullet has to change directions. Changing a direction is a loss of speed no matter how small the value is. If I change direction 4-20x within the barrel velocity has to be lost. Even if its only 5fps... or 150fps... We have a shooter who shot a test AB .338 bullet at 300gr at 3450fps with no bolt set back. Now to make the barrel survive that for a few thousand rounds..
