AR-15 Barrel Spec Questions

[tacstar]

What is the difference between a 16" barrel with a 1-7" RH Twist & a 1-9" twist? What are the advantages of a fluted barrel?

Various manufactures use different rifling twist,for instance Colt using a 1-7" on its current line of carbines & Armalite uses a 1-9"

Are there any advantages to a mid-length barrel?

 

[gazpacho]

1-7" will shoot heavier bullets (>60gr) well, but lighter bullets (<50gr) will exhibit poor accuracy. 1-9" will shoot reasonably well up to 65gr. This is a generality, and individual barrels will vary.

A fluted barrel of a given weight will be stiffer than a non-fluted barrel of the same weight. The fluted barrel should exhibit better accuracy.

The longer the barrel, the higher the velocity.

You should read the link below
http://ammo-oracle.razoreye.net/

 

[mljdeckard]

The current military spec is for 1/7. The main reason for this is to stabilize tracers. The only reason most of the rest of us need a twist that tight (or tighter) is if we are using exceptionally long bullets.

A fluted barrel saves weight and dissipates heat, to some degree. I wouldn't base a decision on whether or not to buy a barrel on whether or not it was fluted.

More so than mid-length barrel, many consider a mid-length gas system to be optimal.