Barrels 101

[isakhnov]

Well it depends on several things. For instance, a 1/7 twist barrel shoots 55gr ammo very well to about 100yds. Past that we see the groups open up a lot. Same with the 1/9 twist barrels. At about 100yds, 75/77gr ammo does pretty well, but as you go farther out, your group sizes can open up.

So if you want to shoot heavier grain bullets at distances over 100yds, stick with a 1/7 twist barrel (which is what I shoot).


C4

Thanks, that makes sense. I'm not planning to go long with the carbine and will be looking at .308 for that purpose some time later (and that opens another set of questions but probably for a different board )

[SHIVAN]

Bump...

[sinister]

http://technology.calumet.purdue.edu...0Part%20II.pdf

http://technology.calumet.purdue.edu...lsonAR-15s.pdf

[eternal24k]

this should be stickied without a doubt.

[Alex V]

Inconel

seems that 4150/CMV is hard to beat for the platform...

Knowing how much an Inconel exhaust valve costs, I can only imagine how much an Inconel barrel would be lol.

Awesome post, very informative! Thank you

[mkmckinley]

Thanks for the writeup; very informative and concise.

[hikeeba]

this should be stickied without a doubt.

[light-hearted jab made in jest] And finished, too.[/light-hearted jab]

http://technology.calumet.purdue.edu...0Part%20II.pdf

http://technology.calumet.purdue.edu...lsonAR-15s.pdf

Those are very interesting articles. I'd like to track down the other articles in the series. Thank you for posting those up.


A few months ago I researched barrels for my first build project. I scoured the Internet almost daily for several months before finally making a decision. Even though my research led me to M4C numerous times - sometimes to threads I had already visited several times - I never recall seeing this thread. I think I can work The Google pretty well, and thought my search terms within applicable topics were widely varied. Dang. My own process could have been much simpler if I had only discovered this thread first.

Thanks you for your time and info, Mr. Davis.

[dewatters]

Would it be an exaggeration to suggest that the steels that are easiest to rifle by single-point cutters and broaches are also the fastest to wear out from use? The introduction of button rifling and then cold-hammer forged rifling offered the ability to economically rifle harder steels.

The ironic thing is that several Fudd rifle companies were using CHF barrels nearly four decades ago. Back in February 1971, "American Rifleman" ran the second of a three-part article by Jac Weller on the construction techniques used by US firearm manufacturers. Remington, Ruger, Weatherby, and Winchester were all cited as using CHF barrels for at least some calibers and models.

According to Roy Weatherby's biography, he was using CHF barrels in his Mark V rifles as early as 1959. (They were made by Sauer at the time.)

In his 1977 book "American Rifle Design and Performance", L.R. Wallack noted that Winchester was still producing CHF barrels, and their representatives had even claimed that they were the only major sporting arm manufacturer to chamber their barrels in the same process.

[dewatters]

Those are very interesting articles. I'd like to track down the other articles in the series. Thank you for posting those up.

The other CHF articles can be found here:

http://technology.calumet.purdue.edu/met/higley/

[sniperfrog]

Would it be an exaggeration to suggest that the steels that are easiest to rifle by single-point cutters and broaches are also the fastest to wear out from use? The introduction of button rifling and then cold-hammer forged rifling offered the ability to economically rifle harder steels.

Actually, barrels that are button rifled or hammer forged have to start out softer in order to be rifled. In the articles posted above about hammer forging, the author stated that the blanks are around 24-25rc before going in to the hammer forge machine, then come out of the machine about 30rc. I believe that button rifling will also work harden the bore.

A Kreiger or Obermeyer cut rifled barrel will also be around 28-30rc. Alot of high power and benchrest shooters say that cut rifled barrels last longer than buttoned.