Gain twists now available

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Obtunded

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I have been in discussions with Krieger and they are now able to produce gain twist barrels in limited calibers at no additional cost.

6mm - 1:14" - 1:13.2"

6mm - 1:9 - 1:8.5"

6.5mm -1:9 - 1:8.5"

Lester Bruno has been doing the R&D on behalf of Krieger and the results are reported to be outstanding. Due to an exclusivity arrangement with Bruno's, these will be available for production after May 30th but we can order them now.
 
So these barrels just barely gain. Sounds like just enough to improve sealing. I had Ron make me a slightly gaining 30 cal (15-13.5) several years ago and it worked very well. In the end, the uniform twist barrels are good enough that the gain twist will be considered a success as long as it works just as well. It has ever been so. Still, it's interesting to see a known barrelmaker trying the minimal gain idea (again). Regards, Bill.
 
Some believe that if the bullet enters the rifling more gently, accuracy is enhanced. There might be a slight velocity gain as there would be less gas energy used to over come the torque as the bullet enters the rifling of the slower initial twist and it is already moving when the twist tightens up; although given the slight gain of these barrels, it would seem an unlikely advantage. I think the concept is sound enough, but I would like to see it proven accurate and with "more" gain so that the initial twist would be slower. The design though becomes complex in that the gain needs to be barrel length specific. I'm trying to envision how a 1:9 to 1:8.5 would look in a 20" barrel compared to a 30." How would this effect the target shooter whose barrel develops a worn throat? When he must shorten and rechamber his barrel, presumably an inch or two of less barrel length would have an impact on the amount of gain.
 
It has been observed that the actual twist of the rifling throughout the barrel may not be absolutely uniform, end to end. It can change slightly. Note that the gain twist in these barrels is slight. This slight acceleration would guarantee that there is no slight reduction in twist rate resulting from manufacturing variation.
Given the quality of these barrels, you would have to do serious comparison testing with quite a number of barrels to determine if there was a demonstrable advantage, uniform twist vs gain twist.
 
Gain is relative to barrel length. Minimal gains over long barrel lengths seem a waste to me, but with short barrels, there would be more of an "impact".


If it were me, I wouldn't bother. How do you make a .1MOA barrel significantly better? But just like 5R rifling, Barrel Break-In, Moly Coating, and Rogaine, there are many things that shooters brainwash themselves into believing it makes a measurable difference.

Go with what floats your boat.
 
Obtunded said:
If it were me, I wouldn't bother. How do you make a .1MOA barrel significantly better? But just like 5R rifling, Barrel Break-In, Moly Coating, and Rogaine, there are many things that shooters brainwash themselves into believing it makes a measurable difference.
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I use rogaine on all my barrels. Still waiting for them to grow their own sasquatch suit though.
 
The one demonstrable advantage to a gain twist barrel is that the grooves in the bullet, produced by the lands in the barrel, remain sealed throughout the bullets travel up the barrel. It takes very little gain to accomplish this.
Many years ago, Manley Oakley, a Washington BR shooter, made up a device to verify twist rate throughout the length of the barrel. He found the more uniform the twist rate, the more accurate the barrel. However, a consistent gain didn't seem to have any ill effects. Not a real surprise but Manley figured his device would help him to pick a good barrel with greater certainty. I can't say if it worked out for him but he spent as much time looking at an errant shot and muttering as the rest of us did. Regards, Bill
 
I was told that the main advantage to the gain twist was that it lowers your pressure curve. That is right from Ron him self.
 
trda said:
I was told that the main advantage to the gain twist was that it lowers your pressure curve. That is right from Ron him self.
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Without the complex instrumentation to measure that, that is a theoretical advantage, but it is certainly one of the presumed advantages.

Lester Bruno - one of, if not the best Benchrest shooter in the world (and the owner of Bruno's shooters supply) - is a huge fan of Krieger barrels and he was looking to improve upon the performance of his 6PPC's. He persuaded Krieger to produce gain twists on the condition that he would do all of the testing, and in return for the promise that he could have exclusive access to these barrels until after the big NBRSA match in May. Anyone that shoots PPC's in benchrest knows that these are generally shot at insanely high pressures. The gain twisting is apparently very successful.

Gain twisting was the domain of black powder rifles with a typically poorer fit between bullet and barrel, and as Bill mentions, its function was to help obturate the bullet.
 
One of the major advantages of gain twist is the reduction in stree on the projectile. Large caliber arms (20 mm and up) often use gain twist to reduce the stress on the driving band. Often these barrels will start at 0 twist (ie parallel to the bore) and gain until leaving the bore at the desired twist.

Reducing stress on the projectile at the bullet rifleing interface is a "good thing" as it will likely increase accuracy and as previously noted allow or maintain a better seal in the bore.
 
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