Twist Rate (#1)
- For dual use in .30 calibre (i.e. both supersonic and subsonic ammunition),
the very best compromise is a 1:10" twist
rate. Our extensive testing has proven that there is NO accuracy
supersonic high-velocity ammunition, and that with the correct
subsonic ammunition, this twist rate will give more than acceptable,
use with subsonic ammunition ONLY, a 1:8" twist rate
is best. This gives added stability and permits the use of less
than optimal projectiles. The use of the 1:8" twist will mean
that this gun is dedicated solely to the use of subsonic ammunition.
- We are often asked what is the best twist rate for use with
different calibers of subsonic ammunition.
Here are some
basic guidelines that will help you to achieve the best results:
For subsonic pistol calibers, the factory barrel/twist is usually
just fine, as most pistol ammunition is just marginally supersonic
anyway, with a very few exceptions.
Rifles: First of all, if you are going to go to the expense and
trouble of creating a platform for use with a suppressor, it only
makes sense to pitch the factory barrel and have it replaced with
at least a decent mid-grade tube.
Companies such as Schneider, Shilen, Douglass and several others
can provide you with an air-gauged and properly finished barrel,
installed and threaded by them for in the $300 range. This is just
$100 more than the cost of the tax stamp for your suppressor, and
will ensure that you do not experience accuracy and safety problems
due to a poorly finished or inspected barrel, and is therefore
worth the investment!
is almost always enhanced by this move, and for some unknown
factories still make .308 barrels with
the obsolete 1:12" twist rate, and 5.56/.223 rifles using the 1:12" twist rate.
For .308, 1:10" is best for dual purpose use and for 5.56/.223, 1:7" or 1:8" is best if the operator wishes to use both supersonic and subsonic ammunition.
While you *might* get lucky with the factory tube, often it is
the source of many headaches when trying to utilize subsonic and
even supersonic ammunition. This is true regardless of the original