I am building a Navy Mk12 style 5.56 rifle currently but I cant decide on which barrel, my options are 20'' Spiral fluted barrel with either 1/7, 18, or 1/9 twist rates. I have been reading a lot about this subject and concluded that the 1/8 would be the best rate for shooting longer ranges with this barrel length, am I on the right path here?
From what I understand the 1/7 will over stabilize and cause lower velocity in a 20'' where a 1/9 can under stabilize rounds. If I were to have a 14.5'' barrel the 1/7 would be the better choice correct?
I am trying to shoot a heavier (70-79gr) match grade round through the 20'' for best accuracy and perimeter engagements with lighter standard rounds for practice and up close work if need be.
Thank you for the help.
Originally Posted By glndrums:
I am building a Navy Mk12 style 5.56 rifle currently but I cant decide on which barrel, my options are 20'' Spiral fluted barrel with either 1/7, 18, or 1/9 twist rates. I have been reading a lot about this subject and concluded that the 1/8 would be the best rate for shooting longer ranges with this barrel length, am I on the right path here?
From what I understand the 1/7 will over stabilize and cause lower velocity in a 20'' where a 1/9 can under stabilize rounds. If I were to have a 14.5'' barrel the 1/7 would be the better choice correct?
I am trying to shoot a heavier (70-79gr) match grade round through the 20'' for best accuracy and perimeter engagements with lighter standard rounds for practice and up close work if need be.
Thank you for the help.
I would go with 1/7 with the heavy rounds. I don't think you will "over stabilize" which I don't think is possible. Once it hits something more dense then air it will instantly un stabilize. It might cause more drag in a tighter twist barrel but you can make up for that in barrel length. Barrel length effects velocity not accuracy, unless you get some weird harmonic problem.
