Gain Twist barrels?

[TXAoudadKlr]

What everyone's opinions on them? I'm really thinking of going with 1:9.75 to a 1:8.7 or something along those lines once I shoot the barrel out on my 300 and rebarrel in a twist that will handle the Berger EOL hybrid. Or would I be better of just going with standard twist barrel.

 

[Varminator 911]

I'd just go a standard twist unless you are needing something extreme. All the Berger bullets use reasonably standard twist. The gain twist is for shooting something really long like a 400 grain copper 375 that might need a 7 twist.

 

[RevJim]

Back in 2007 I was given a custom rifle in 338 RUM. It had a gain twist...it went from almost nothing to 1 in 10, if I remember right. anyhow, it had a 25 inch barrel and I only shot the Nosler 180AB, but I got it to a safe 3500fps. It was accurate, and super flat shooting ( +2@100 and only -5"@400yds ( at 4000ft altitude) I killed a big aoudad with it at 250yds at almost 3000ft. ( not that it mattered) the barrel was made by a "now defunct" company out of Kallispell, MT is all I know. Some say they are not worth it. I know that historically artillery has experimented with gain twists, but I know of no country that uses it in my lifetime. so...just get a standard for the twist you really need for the weight/length you will be using, but have a ball doing it!

 

[TXAoudadKlr]

Bartlien recommends a 1" or less gain for lead core bulleys from the email they sent me. Obviously you can get a bit more radical with the twist gain with solids. I'm just bouncing some ideas around in my head seeing if they'd be worth exploring.

 

[Varminator 911]

Bartlien recommends a 1" or less gain for lead core bulleys from the email they sent me. Obviously you can get a bit more radical with the twist gain with solids. I'm just bouncing some ideas around in my head seeing if they'd be worth exploring.

The one inch or less gain for lead core is probably because too much gain would overly stress the jacket. Whereas a copper solid won't be ripped apart by the change in twist. And some solids only engage the drive band. So the bore riding part of the bullet won't be affected at all.

For Berger bullets stick with a constant twist. The needed twists are easily available. Using a gain twist with one inch of gain would make no sense to me.

 

[Frank in the Laurels]

For the most part...worthless !!

 

[TXAoudadKlr]

It's looking like a Lija 1:8 then.

 

[Trnelson]

My next barrel for my 6.5/06 is going to be a 26" gain twist. 1-12 to 1-7 I want to shoot the 150g and 160g bullets. Same thing is going on my 264 win mag. My thought is it will help reduce some of the copper fouling I'm getting in the first 12" of my current barrels. The 143 ELDX is shooting pretty well out of my 264 but I'm having to de-copper it every 45 to 55 rounds at 3,168 fps. I *think* I'm getting some skeiving of the jacket however I haven't recovered any bullets that I could learn anything from to substantiate that they've all been too damaged and in pieces. Maybe I need to shoot a bit further than 50 yards... Just my $.02

 

[TXAoudadKlr]

My hope was for a softer entry to the lands in hopes of possibly driving it faster before it pressures out.

 

[azsugarbear]

I own a .270 with a gain twist barrel. It belonged to my grandpa and was built in the 1960's. Back then, the gain twist was reputed to have different mojo. I remember him telling me it helped with velocity (probably true) and helped the bullet 'plane down' instead of dropping in an arc (probably not true). In his day, they didn't have premium designed bullets or heavy/long for caliber bullets. Just the standard stuff. The bullets handled the 2.5" increase in gain twist just fine. But I have to believe that if there was any substantial improvement, somebody would have proven it by now. Just my two cents.

 

[Varminator 911]

My hope was for a softer entry to the lands in hopes of possibly driving it faster before it pressures out.

The copper bullets with a drive band not only give higher velocity but are suited to the gain twist barrels. Some of the bullets have multiple drive bands like GS Custom, Hammer, and Barnes:

GS CUSTOM BULLETS - The Difference between Drive Bands and Groooves

While others have a single drive band like flat line and cutting edge:

Flat Line Bullets: Hands-On Tests & The 4700 Yard Shot - PrecisionRifleBlog.com

https://cuttingedgebullets.com/cgi-bin/commerce.cgi?search=action&category=MTH1

 

[sable tireur]

Trnelson,

I *think* I'm getting some skeiving of the jacket however I haven't recovered any bullets that I could learn anything from to substantiate that they've all been too damaged and in pieces. Maybe I need to shoot a bit further than 50 yards...

Skiving, by definition is a sectioning or slicing through of an object, think slices of bread from a loaf. So yes you might be getting some of this if the jacket was being penetrated completely. Otherwise it's just engraving.

However, the manufacturing process for making bullets can include a 'skiving' operation inside the nose to reduce the stress of forming the tapered shape to the hollow point.

TXAoudadKlr,

My hope was for a softer entry to the lands in hopes of possibly driving it faster before it pressures out.

A softer entry into the lands is not accomplished by a slower twist evolving into a faster twist since the bullet is still colliding with the front of the lands as always. If this is your goal then the simple solution is to use a much longer and more gradual throat. I've had Dave Kiff make several of this style for me to experiment with since this is often a topic for discussion so I wanted to play with the idea and see exactly what might become of it.

Like the oft cursed Weatherby 'freebore', this style of chamber reduces the initial pressure spike a tiny bit but makes the transition into full land contact a more gentle process without the need for gain twist. I've been shooting gain twist barrels in several variation for over 20 years and I still have yet to see a verifiable positive aspect.

If a softer entry is a goal I certainly wouldn't use a Lilja 3-groove ever. Your best bet would be a 5R, 5C or even a ratchet if necessary but something with a polygonal-type form.

Regards.