![]() 1-in-8 Inches Twist Rateįor a 16-inch general-use carbine, the 1-in-8 twist is about as versatile as it gets. With longer barrels and commensurate faster velocities, this twist can be more forgiving. My personal 16-inch Rock River Arms carbine with a 1-in-9 twist does fine with ASYM's Tactical Match Grade 77-grain OTM load but has shown signs of instability with handloads using the 70-grain Barnes TSX - unless the bullet is pushed to maximum velocity. This twist will stabilize most traditional bullets up to 75 grains, and monolithics up to 70 grains - but they do so right at the edge of the envelope so not all rifles will do it. The 1-in-9 is a great compromise twist rate-not too fast to cause problems with the 55-grain bullets, but fast enough to stabilize all but the heaviest bullets under most circumstances. This is the beginning of the road for the shooter wanting to take advantage of the heavy bullet trend. In my mind, however, the 1-in-10 twist is just a bit too restrictive. If you're happy with 55- and 62-grain FMJ bullets, you don't need any more twist than this. This is a good twist rate for lighter bullets and will also generally stabilize projectiles up to 69 grains, such as Federal Premium's Sierra MatchKing BTHP load. My first centerfire rifle was a Ruger Mini-14 with a 1-in-10 twist. Doubletap's 55-grain Nosler Ballistic Tip load generates 3,300 feet per second of velocity out of a 22-inch barrel, and will easily stabilize in this twist rate. 223 bullets, this twist rate will do fine for your needs. If you hunt prairie dogs or coyotes with lightweight. Conventional wisdom suggests this twist rate is perfect for bullets in the 55-to 60-grain range, though most will stabilize the common 62-grain FMJ rounds. Though far better than the 1-in-14 twist, it is still unsuited for some of the premium loads developed over the past decade. This is the slowest twist still seen in large numbers on AR-15s and other. If achieving maximum velocity with light bullets is your goal, this may fit your needs - Winchester's 45-grain JHP load is a screamer at 3,600 feet per second. Although 1-in-14 barrels can stabilize 55-grain bullets used by the original M16, it's really better suited for bullets up to 50- and 52-grains-most of which fall into the varmint and target category. This is the least-versatile twist rate you'll see in the 5.56x45mm/.223 Remington chambering. You're unlikely to find a 1-in-14 barrel on any AR-15 produced in recent years, but they do exist and you may encounter them on a bolt action rifle on occasion. Let's take a look at the commonly available twist rates used in conjunction with the 5.56mm NATO/.223 Remington chambering. Civil war muskets such as the 1861 Springfield used extremely slow twist rates (1-in-78") to fire heavy lead bullets with relatively good accuracy, while modern AR-15-style rifles use barrels as fast as 1-in-7 to stabilize long-for-caliber projectiles. There is no "golden" twist rate for all firearms. ![]() This spin stabilizes the bullet in flight, much the way a football is "spiraled" by a quarterback.ĭetermining proper twist is a factor of bore diameter, velocity, bullet weight and even bullet construction. "Rifling" are the lands and grooves impregnated into the barrel's interior that impart spin on a projectile as it travels down the bore. With so many bullets and twist rates available these days, keeping track of which ammunition is compatible with your barrel can be overwhelming.īefore we get into the weeds on individual twist rates, let's take a minute to discuss rifling in general. ![]() In more modern times, bullets for military and civilian use have migrated to longer, heavier designs and twist rates have been altered to stay in sync with this progression. Shortly thereafter, nearly all M16s and M16A1s were being issued with faster 1-in-12-inch twist barrels. The earliest issued variations of Eugene Stoner's "Black Rifle" came with relatively slow rifling twist rates of 1-in-14 inches. military first adopted the M16 rifle in the 1960s, the M193 cartridge and its 55-grain bullet was standard. ![]()
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