Gain Twist Barrels

[Bergerboy]

Is there an advantage to them? The only thing I can hypothesize is a lower initial pressure spike when the bullet first swages into the bore. Is this all?

[shooter]

I didn't think Savage offered them....

I have an RKS gain twist and notice higher than average muzzle velocity with it vs a non gain twist. Shoots very well and as mentioned about 100 fps higher than expected initial FPS.

[Bergerboy]

Originally Posted by shooter

I didn't think Savage offered them....

I have an RKS gain twist and notice higher than average muzzle velocity with it vs a non gain twist. Shoots very well and as mentioned about 100 fps higher than expected initial FPS.

100 fps is interesting. Thanks.

[Robmcleod82]

They seem to foul less and seem forgiving during load development.

[roger]

Originally Posted by shooter

I didn't think Savage offered them....

I have an RKS gain twist and notice higher than average muzzle velocity with it vs a non gain twist. Shoots very well and as mentioned about 100 fps higher than expected initial FPS.

Hiya shooter! How's things??
I'm in the process of r and d on my 257wby rks.
With the slowest powder currently avaible im getting 3875fps and printing loonie groups in trials. Easily 200 over my pre gain twist reloads.
Using Barnes bullets assisted greatly.
I'm I convinced there an improvement. At this point. Yes.

[Bergerboy]

Is there a significant jump in price point going from normal to gain twist?

[Dick284]

Originally Posted by Bergerboy

Is there a significant jump in price point going from normal to gain twist?

Nope.
I have 2 gain twist tubes, one on my 25'06, which gets obscene velocities (85's@3800, 100's@3440)
The other is on my 280AI(150's@3050)
Dunno how a straight twist tube would have been, but RKS seems to turn out some ok barrels.

[Bergerboy]

Originally Posted by Dick284

Nope.
I have 2 gain twist tubes, one on my 25'06, which gets obscene velocities (85's@3800, 100's@3440)
The other is on my 280AI(150's@3050)
Dunno how a straight twist tube would have been, but RKS seems to turn out some ok barrels.

Those are some serious numbers. I am regretting not considering a gain twist on my last custom....time for a new one I guess

[normanrd]

Mine must be the exception. It is the 4th barrel on my 300 weatherby and is the least accurate of them all. It will hold MOA accuracy, usually and It will shoot a 180 at 3165 fps, which is no screaming hell from a 26" barrel. I would not go out of my way to buy another.

Imo,

Norm

[catnthehat]

Given a choice I will go with an RKS gain twist every time!
I've owned many , mostly in 6.5, but they were all very accurate barrels.
Cat

[DaleJ]

Good barrels if you stay short. Gain twist adds pressure. Long barrels build more pressure than short barrels. When you combine GT and long barrel some "starting" loads are hot!

[Big Sky]

Originally Posted by DaleJ

Good barrels if you stay short. Gain twist adds pressure. Long barrels build more pressure than short barrels. When you combine GT and long barrel some "starting" loads are hot!

What is considered long for a gain twist barrel? Is it dependent upon caliber?

Is Ron still making barrels?

[catnthehat]

Originally Posted by Big Sky

What is considered long for a gain twist barrel? Is it dependent upon caliber?

Is Ron still making barrels?

Yup, he recently finished reboring a 243 to 25 super for a buddy of mine and is still making barrels - he and his son .
Cat

[Big Sky]

Good to hear!!
I picked up 2 barrels from him about 18 months back. The first one has more than met my expectations. The second one isn't in use yet.

[Bergerboy]

Originally Posted by DaleJ

Good barrels if you stay short. Gain twist adds pressure. Long barrels build more pressure than short barrels. When you combine GT and long barrel some "starting" loads are hot!

How do they add pressure?

[DaleJ]

Originally Posted by Bergerboy

How do they add pressure?

If you gain velocity without decreasing friction you've added pressure, or developed a longer peak pressure span. Gain twist barrel would increase friction. They are a bugger to "slug". Increasing barrel length increases velocity while adding friction. Seen long, gain twist barrels develop high pressure before velocity obtainable was reached.

[Mateo]

Originally Posted by DaleJ

If you gain velocity without decreasing friction you've added pressure, or developed a longer peak pressure span. Gain twist barrel would increase friction. They are a bugger to "slug". Increasing barrel length increases velocity while adding friction. Seen long, gain twist barrels develop high pressure before velocity obtainable was reached.

I'm thinking of using a gain twist in my 6.5mm build. I plan to run H1000 which will run at fairly low pressures. Will this also take advantage of the gain twist barrel? ( low pressure)
I can understand how 5R rifling has a couple advantages. Gain twist makes sense just thinking of it. The way I see it is the initial pressure spike will be less than a regular barrel because the bullet gets started 'easier' with a bit less friction. Then as the twist tightens the bullet meets more resistance right near the muzzle and you get a last bit of extra pressure right before it exits the barrel hence the added velocity some are seeing. I also believe gain twist will be easier on barrels because of this. Or rather, it will be easier on throats. This pressure build-up at the end will mimic the effect hand lapping does when you want the bore to be tighter at the muzzle. This is supposed to give the best in velocity and accuracy. Of course a properly hand lapped barrel can't be beat, but gain twist must also work in this regard. I've read of gain twist barrels winning comps quite a bit so they do work. It would be nice to see 2 identical barrels, on with gain twist, one without and really get some data on the differences.

[DaleJ]

Originally Posted by Mateo

I'm thinking of using a gain twist in my 6.5mm build. I plan to run H1000 which will run at fairly low pressures. Will this also take advantage of the gain twist barrel? ( low pressure)
I can understand how 5R rifling has a couple advantages. Gain twist makes sense just thinking of it. The way I see it is the initial pressure spike will be less than a regular barrel because the bullet gets started 'easier' with a bit less friction. Then as the twist tightens the bullet meets more resistance right near the muzzle and you get a last bit of extra pressure right before it exits the barrel hence the added velocity some are seeing. I also believe gain twist will be easier on barrels because of this. Or rather, it will be easier on throats. This pressure build-up at the end will mimic the effect hand lapping does when you want the bore to be tighter at the muzzle. This is supposed to give the best in velocity and accuracy. Of course a properly hand lapped barrel can't be beat, but gain twist must also work in this regard. I've read of gain twist barrels winning comps quite a bit so they do work. It would be nice to see 2 identical barrels, on with gain twist, one without and really get some data on the differences.

I think "hand-lapped" barrels are sales promotion hype. One Kreiger barrel in 308 shoots great, a 20-10:1 RKS in lighter profile shoots better. Quality is easier to maintain in a one-man shop. Lucky to have two world class barrel barrel makers in this province. Latest Jury barrel shoots great. I expect the next Jury barrel I use will shoot as good.

Look down the bore any hand-lapped barrel and you will slight waves in the bore. Taking a hand-lap to a precisely cut rifled barrel is insane. Would you buy a vehicle equipped with an engine that had pistons filed by hand and cylinders tapered by a hand-lap?

[singleshotom]

I have more gain twist barrels then I should admit to. With Ron being a close friend of mine and him letting me play with his machines, I have had the opportunity to learn a lot about barrels and making them.
That said neither I nor Ron would say that gain is more accurate then straight twist but there is some noticeable advantages.
Many shooters that used both types in a specific caliber, claim that they find far less throat erosion with GT.
An most shooters find no loss in accuracy going to GT with many saying they find if anything find them a bit better.
Others say there is less cleaning required to maintain accuracy.
As far as "the price" for a barrel, they are the same for Straight or Gain.
So as I see it, what do you have to lose, its the same price and if the barrel lasts you a few hundred rounds more, shots as accurate or a bit better, why not do it?
And have fun playing with something new to you.
sst

[singleshotom]

Just one more point about Ron's barrels, they choked a bit at the muzzle end of the barrel.
This is a fact with all RKS barrels either gain or straight.
Another fact with gain twist is that the grooves are slightly narrower at the muzzle end then at the chamber end. This is hard to measure but the physics
of how Ron cuts his GT barrels produce this effect.
So a GT has a choke, tighter twist, narrower grooves all happening as you get closer to the muzzle end of the barrel.
sst

[Mayhem42]

Had a mark v stainless action and threaded a 26" gain twist 6.5 on it, shoots incredibly fast obviously, and is really accurate.

Dale, the 165 rbbt stabilize to at least 500 out of it, have not attempted farther. I will ask my Dad what he is loading it up with and get back to you.

Bartlein barrels at one time offered gain twist barrels

as well. Give them a ring.

[buckbrushoutdoors]

Can you re bore with a gain twist? Or would one have to rebarrel

[singleshotom]

You bet rebore's or new can do either way.
sst

[Leeper]

A gain twist most likely increases velocity because there is less leakage as the changing twist seals the groove made in the bullet.
I believe a gain twist for jacketed bullets should not gain too much. I like no more than about a 30% gain.
On hand lapping, lapping is primarily used to achieve a desired surface finish but can be used to slightly alter dimensions as well (bring a lunch). A properly made and used lead lap will not produce a wavy finish and can, in fact, be used to correct a wavy surface.
In barrels, what is referred to as hand-lapping by some makers might be more accurately described as hand polishing because they are not using a cast lead lap but a resilient material charged with lapping or polishing compount. The use of a resilient backer will perpetuate a wavy surface. Lapping is an important machining process and has been used by tool and die makers to finish work for centuries and is still used as a finishing process today. Sometimes, the lapping is done by machine but just as often, it is done by hand.
By the way, the very best, straightest, smoothest, and most consistent (dimensionally) barrel I have ever had in the shop was a 30 caliber (a 12 to 10 gain twist)from Ron Smith. I have never seen a cut-rifled barrel (or a barrel produced by any other means), from any maker, which was a free of tool marks as was this barrel. I called Ron and suggested that I could see no reason why every barrel I bought shouldn't look just like that one and he told me to keep dreaming! Great barrels. Leeper

[Mateo]

What are RKS barrel prices like compared to.... Say benchmark?

[Dick284]

Mateo:
Call him and ask.
403-631-2405

[HW223]

Originally Posted by DaleJ

I think "hand-lapped" barrels are sales promotion hype. One Kreiger barrel in 308 shoots great, a 20-10:1 RKS in lighter profile shoots better. Quality is easier to maintain in a one-man shop. Lucky to have two world class barrel barrel makers in this province. Latest Jury barrel shoots great. I expect the next Jury barrel I use will shoot as good.

Look down the bore any hand-lapped barrel and you will slight waves in the bore. Taking a hand-lap to a precisely cut rifled barrel is insane. Would you buy a vehicle equipped with an engine that had pistons filed by hand and cylinders tapered by a hand-lap?

I would think of an unlapped barrel as unfinished, I would not even consider shooting a barrel that is not lapped in competition at this time, Nobody in the top fifty at the nationals were shooting an unlapped barrel , while these barrels are fine for hunting,in sbr at the "world class" level there are no RKS and no Jury Barrels as of yet,(check the equip lists for the matches)
I check every barrel with a bore scope, I video and take stills of the bore ,the lands and general interior finish, I have never seen and unlapped barrel that looks as good as a lapped (cut or button).
Krieger does not offer a gain twist barrel but Bartlien does ,the ones I am familiar with are only a small gain ,such as 13.85-13.75 and 14.5-13.75,there are some others as well.as you can see they are not big gains , the idea being that the bullet is always in a positive engagement as it moves down and out the bore. I have seen competitors win with both gain and straight twist .

[Advent721]

Originally Posted by catnthehat

Given a choice I will go with an RKS gain twist every time!
I've owned many , mostly in 6.5, but they were all very accurate barrels.
Cat

x2!

[DaleJ]

Originally Posted by HW223

I check every barrel with a bore scope, I video and take stills of the bore ,the lands and general interior finish, I have never seen and unlapped barrel that looks as good as a lapped (cut or button).

That's a fantastic idea.