Titanium barrel ?

Taurus and I think S&W have a couple models that are primarily made out of Titanium alloys. They are super light and from what I've heard perform as advertised. However the biggest problem with a titanium revolver chambered .357 Magnum and a 4" barrel is that it weights very little and moves around in the hand a bit.

Those things aside, the barrels themselves are made out steel lined titanium. I guess the properties of titanium makes it impossible to cut rifling into it. All metal has it's drawback. Where one strength is augmented, another flaw becomes evident.

I think the comment about stress relief after making a barrel has more to do with a 6er and some buddies than it does with machining steel.

Some years ago, there were a few extra lightweight hunting rifles made with solid titanium barrels. Spaceage hype over titanium did not guarantee it for contact with blazing nitrocellulose and whizzing bullets. Barrel life was a few hundred shots. Might be ok if all you did was sight it in and hunt bighorn sheep, but everybody likes to at least think they will practice a lot, so they did not sell well.

Would chrome plating the bore make it last? I dunno.

How about a nice Christensen carbon fibre barrel (with steel bore?)

Its been discovered by the gun companies that titanium is not suitable for rifling.

Among the other strange properties of titanium, rifled bores tend to UN-rifle themselves. This was discovered after titanium barrels came back with the rifling literally fading away back to a smooth bore.
Since then, titanium barrels are lined with a stainless rifled liner inside the outer shroud.

Titanium has a strange "desire" to return to a previous shape especially if warmed.
This was discovered in the US Navy Weapons Lab at China Lake California.
The lab was investigating titanium for some project and the lab people were beating dents in a titanium plate with a hammer.
At lunch time, someone put a dented plate in the window in the hot desert sun.
When they came back from lunch, the dents had ironed themselves back out.

This strange property was later used to manufacture the FlexOn titanium eye glass frames that can be bent into pretzel shapes.
The frames will tend to return to shape, especially if worn in warm weather.

It also galls and most grades lose strength dramatically above 800-1100 F.

FYI

Titanium is also a VERY POOR conductor of heat, so definately not good for rifled barrels that are shot rapidly with MAG. rounds. That is why Titanium is so hard to machine because it gets harder as it gets hotter and will actually alloy "weld" itself to the high speed steel tool tips of milling machines and lathes.

There is certain Titanium alloys that would make excellent barrels, but because of the "work hardening" aspect when they get rifled with the standard "button rifling" or Hammer forging they get galled or stuck. Cut rifling would work but again would take 3 times as long than a steel barrel because of having to go really slowly..

Then there is also the huge cost compared to other metals.

A much better way being refined by several companies is using a Chrom Moly Rifled insert with a anodized Aluminum outer shell. Lighter weight, long life rifling and great heat dissapation. They still trying to work out the ratio of steel and aluminum thickness so the barrels would not expand so much as to make the bore to big for the bullets to contact the rifling. This might be solved by mixing Aluminum and Titanium to make a "Memory metal".

Anyways with how fast Technology is going maybe the will use nano carbon tubes/fibers to make barrels in the future.

Stress relieving is done after rifling, because no matter what method you use to make the rifling, it sets up stresses in the barrel that will later manifest itself in strange & unpredictable warping when the barrel heats up during firing.

rc

The ultimate rifle barrel material would be ceramic. I know the army and one other private company have experimented with a zirconia barrel wrapped with carbon fiber. It has a great deal of benefits, including heat transfer to the round and not the barrel or chamber, etc, however the expense of rifling is the main issue.
I wonder if anyone has experimented with an aluminum wrapped smooth bore ceramic barrel?

For a high-tech musket?

At least one of the Army fletchette shooters had a slow rifling twist to help discard the sabot cleanly.

Titanium is also a VERY POOR conductor of heat, so definately not good for rifled barrels that are shot rapidly with MAG. rounds. That is why Titanium is so hard to machine because it gets harder as it gets hotter and will actually alloy "weld" itself to the high speed steel tool tips of milling machines and lathes.

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I have personal experience with this after trying to drill out some pocket clip mounting holes for my Emerson knife with Ti liners. The material got so hard I couldn't get anything through it and it bonded to the drill bit. I've heard of people machining a Ti block into a lower receiver, though. I'm not sure it has any great benefit over Al but it would sure be cool. A chunk of Ti that could be machined (very carefully controlling temperature so as not to ruin mills and drills) would be around $100 to $200 so provided one had the skills and equipment it could work. Eventually with atomically precise manufacturing there will be some really exotic materials and methods for making gun parts and practically everything else that would seem almost magic to us. It's not that far away either. A few decades probably.

No problem at all machining titanium once you get the speeds and feeds right. There are plenty of materials that take longer and/or are more difficult to machine, eg, inconel.

Gale McMillan built some titanium barrels and reported on his experience - might even have been on this forum? As I recall conventional bullets acted as unrifling buttons as the barrels tended to smooth themselves out.

There have been some oddball shotgun barrels such as the Winchester Model 59 wrapped barrel.

I fail to see any advantage in this projectile but can relate a story
that might give a little light on what could be expected.

A few years ago when the light rifle craz started I built a complete
rifle out of titanium. It was chambered for 308. I had to use a steel
bolt to bring the rifle up to 5lbs. We tested it for accuracy tith 10
rounds which was OK and then I borescoped the barrel and found that most
of the rifling and some of the bore was missing for the first 8 inches.
We tried another 10 rounds and an other 8 inches shed the rifling.
Titanium is the worst metal I know of to guald. The barrel was gualding
to the bullet jacket and was ripping it out with every round. You could
picture a titanium bullet gualding to the steel rifling and doing the
same thing.

Gale McMillan

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Sort of reviving a necro post, but since folks are interested..... I have friend who has developed an explosively bonded steel/aluminum barrel that is currently being tested by the DoD on a couple of the new XM2010 sniper rifles. Similar to what you've seen before with steel liner inside an aluminum jacket, but this does it one better with the metals bonded at the molecular level through a proprietary technique. The tests look very promising. I will be anxious to get my hands on a couple barrels for lightweight projects down the road once they become commercially available.

Zak Smith said:

No problem at all machining titanium once you get the speeds and feeds right. There are plenty of materials that take longer and/or are more difficult to machine, eg, inconel.

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The worst I've ever encountered was Hastalloy but once again, proper feeds, speeds AND coolant!

There is a company that will take your barrel, turn it down to minimum diameter and then apply Ti with some sort of plasma spray until it is back up to diameter. They claim it dampens harmonics much better than steel and the barrels are extremely light. Down side is, it are really 'spensive.

Hamilton Bowen built a 26oz revolver in .50AE with a titanium barrel. In his words: "Recoil is not for the squeamish."

Why would you machine a lower out of titanium? It would weigh much more than an aluminum lower.

There are no suitable titanium alloys for anything approaching barrel duties, to my knowledge. Anything from 6Al-4V to Ti Beta-C suffer from excessive galling and poor wear characteristics, which makes them mostly worthless. It also has excessively poor thermal conductivity. When you look at applications of titanium, its not replacing traditional metals used for wear purposes. It's to shave weight or to utilize it's ability to be nearly impervious to corrosion.

Titanium isn't that impressive. It sits between aluminum and steel both in weight and usefulness. We use titanium often for aerospace or space products. It isn't as notoriously difficult to machine as some would believe. Tooling cost and life is about the same as machining hardened stainless steels. Heat removal is the biggest problem due to it's poor thermal conductivity. The difficulty of titanium is a bit of hype and mystique perpetuated by various people to argue excessive price differences on a titanium product over a more mundane metal. While titanium costs quite a bit more than other metals, the price differences on many products are inflated. The raw material cost itself generally plays a small role in the actual cost to manufacture a product. It's machine time that makes up the bulk of the cost for complex parts.

Incoloy, A286, Hastelloy, and Stellite are a bigger pain to machine. While these superalloys can test "soft" on a hardness tester, metals like stellite have a high amounts of carbide in the cobalt matrix, which can be thought of as grains of sand stuck in butter. This is why they use it for high-wear applications, including firearm barrels.

I'm curious if there is a more detailed write-up on that experience. I know that sleeving in aluminum is popular for .22LR and I believe its been tried in centerfire on occasion both using aluminum or carbon fiber. The interesting thing is titanium is such a poor thermal conductor that mirage effects would be delayed for quite a while, but it would conversely take much longer to cool off.

It's definitely a fine way to drop barrel weight but aluminum or even magnesium would drop it more, unless the steel barrel was so turned down in OD so much that it needed the tensile strength of a titanium sleeve to prevent itself from failing. I am actually surprised that the light parts movement hasn't produced any magnesium parts, or use aluminum-lithium alloys in non-critical applications, considering I see so many pointless arguments (and pricing differences) in the AR world between aluminum 6061 vs 7075 parts.

I was told that while Ti is a poor conductor of heat, it doesn't flex and sag as much steel or aluminum when heated. It does bounce but at frequencies that are more constant through it's heat range. These two things lend well to high accuracy at a lower weight.