AR 15 Barell Twist

dav1965

My ar has a 1 in 8 twist bull barell what bullet would be best for it. Thanks David

nononsense

dav1965,

The 1:8" twist rate for the .223 Rem. or 5.56 NATO is normally associated with the longer and therefore heavier Match bullets in the range of 80 grains. This requires that the velocities be developed for the the upper end of the velocity range. Slower might yield degraded accuracy. The current version(s) of the rifles usually have a 1:7" to minimize that degradation and improving the exterior ballistics of the cartridge at longer ranges.

The former idea that the faster twist rate will not allow for accuracy loads when using lighter bullets is false. I regularly use light bullets in fast twist barrels for such pursuits as varminting with great sucess and accuracy.

Load testing with various longer bullets will tell you more than gets written. You should try some of the 75 gr. AMAX, 77 gr. Sierra MK, 80 gr. Sierra MK and the 75 gr. Berger VLD. Of these, I have had the best overall performance in several rifles with the 75 gr. AMAX, although you will have to run your own tests to see what your barrel has as a preference.

Best.

perry shooter

one in eight twist was made so it COULD stabilize heavier bullets however it Should be able to shoot 55 grain and up all fairly well

tsr1965

Like has been said, the 1 in 8 twist should stabilize the 55 grain and up bullet weights. From my experience the 62 grain and up will see an edge in accuracy, but not to say it is not acceptable with the 55 grain bullets. That said I have seen the Hornady ammo loaded with the 40 grain V-max print 4" groups out of an M-4 Upper, while the Remington 62 grain HP showed 1/2 MOA, both at 100 yards. That was the only load tested under 55 grains too.

Best