Button rifling, hammer forging & cut rifling

[The Sodbuster]

There's been some concern expressed in the post "What Constitutes a Good Bolt-Action Rifle" about the deterioration in rifle quality as evidenced by, among other things, widespread use of button rifling.  I'm not a gunsmith or metallurgist, but I thought button rifling was an improvement over hammer-forging.  Correct me if I'm wrong, but in button rifling isn't a "button" with a reverse impression of the rifling, pulled through the barrel in one pass.  This requires a great deal of force and the grooves are "pressed" into the metal.  No metal is removed, it's merely squeezed out of the way.  I thought hammer forging was similar, but instead of doing it in one stroke, a hammer drives the rifling die through the barrel with repeated blows. 

I would presume both are inferior to cut rifling, in which the grooves are cut and metal is actually removed.  Lots of companies offer cryogenic treatment for barrels to "remove internal stresses" in the metal.  Again, correct me if I'm wrong, but I understood those stresses are the result of metal displacement during the rifling process, and that cutting the rifling doesn't create stresses in the metal. 

What aftermarket barrel manufacturers sell cut-rifled barrels?  I think H-S precision barrels are cut.

[BUSTER51]

I don't think you will find much wrong with any of the methods if it is done right .the end result is all that counts and for a production gun ,you may never notice any diffrence . cut rifleing is said to be the best ,it is slow and expensive .cut rifleing exerts less stress on the barrel and thus is suposed to produce a better barrel .you got the bucks try one .

[Brithunter]

Hi All,

     

I thought hammer forging was similar, but instead of doing it in one stroke, a hammer drives the rifling die through the barrel with repeated blows.

      No this is not how Hammer Forging works. The rifling is in reverse on a hard former made of amaterial like Stellite. This is put into a bored blank and the whole lot introduced to the hammer machine which then procedes to feed the barrel through whilst the hammer hammer then outside which forged the rifling around the former  in the process the barrel is lengthened and the grain structure is alingined with the bore. When finished the former is pressed out of the bore and a finished bore is the result.

      In button rifling the buttone is pulled or pushed through the bore where it swages the rifling into the bore. The trouble is that quite often using this method you get deeper rifling one side than the other  . I had a 9mm pistol and you could clearly see the rifling deeper one side of the bore. For plinking it was OK.

      When you cut steel you set up or expose stresses unless it's been stress relived. But cutting the steel still introduces stresses. I had a Gas op Rod from a SA80 which had coiled like a spiral when it was oil hardened it was the stresses set up but the turning which caused this.

     Cut barrels are suplied by Border Barrels in Scotland and I believe Lija do cut rifling.

[myarmor]

Here is a good read from Lilja... something to think about..
http://www.riflebarrels.com/articles/barrel_making/making_rifle_barrel.htm
-Aaron

[gunnut69]

My understanding was that the Cryo processing alters the crystalline structure of the steel. Stress relieving is usually done as a heat treating process.. Refining the crystal structure can alter the way the material reacts to heating and vibration. It also is supposed to change some of the wear characteristics.

[safetysheriff]

"The Making of a Rifled Barrel" on www.border-barrels.com/articles/bmart.htm tells us how the rifling methods produce differing results.   

but, when you are done reading about the alleged negative aspect of hammer-forging, take a look at the quality rifle builders who use it: Sako, Tikka,  Heckler and Koch, (Remington in the USA).....ETC.   i believe that the smoothness of the hammer-forged barrels and their known accuracy such as in the Vanguard Sub-MOA; the Remington Sendero, Tactical, and Varmint rifles; and others tells us that hammer-forging is superior to button rifling.   

but i recommend you read the article, discount the modest amount of bias in it, and then decide what you like best.

take care,

ss'