What grain bullet is best for 1 in 7 twist?

If you are shooting long range, or want more penetration, you want a heavier bullet in the AR, such as a 62- or (preferably) a 77-grain. While 62-grain bullets prefer a rate of twist around 1:8, 77-grain bullets weights favor a 1:7 twist rate.

What is a 1/7 twist barrel good for?

The 1:7 barrel, found in the M4, M16A4, Mk12 SPR and HK416, can stabilize up to a 90-grain bullet, and handles 70- to 77-grain projectiles across a wide spectrum of velocities.

Why does the military use 1 7 twist?

A 1:7 twist rate indicates that the bullet will undergo a rotation once every seven inches, which, as you might imagine, is a much faster spin. For those who are curious, Guns&Ammo notes that the military uses the 1:7 twist rate. The answer is simple: bullet weight.

What is the optimal barrel length for a 556?

For most loads, 5.56 NATO and . 223 Rem do best with a 16″ barrel and 1:8 twist rate. For . 308 and 7.62 NATO, a 20″ barrel and 1:12 twist rate works best for all loads.

What does 5R rifling mean?

Definitions. 5R is a 5-groove rifling pattern with sloped or angled sides to the lands. All rifling has a certain amount of angle to the sides of the lands as a natural effect of the rifling process. The sides of the grooves are parallel, but the sides of the lands are not and the 5R carries this to an extreme.

What grain bullet is best for a 1 in 8 twist?

1-in-8 Inches Twist Rate For a 16-inch general-use carbine, the 1-in-8 twist is about as versatile as it gets. This twist rate will comfortably stabilize bullets up to 80-grains, and the excellent 75- and 77-grain bullets also work great at a wider spectrum of velocities — which means barrel length isn’t critical.

What size barrel does the military use?

The newer M4 was shortened to make handling easier, with a 14.5″ barrel standard in the military version, though civilian rifle barrels are generally required to be 16″ or longer. But while a 20-inch M16 barrel does shoot straighter than a 14.5″ or 16″ barrel, the shorter barrels are just as accurate.

What is the best barrel length for 300 blackout?

A 9″ barrel is the optimal barrel length for 300 Blackout.

What is the advantage of 5R rifling?

5R reduces projectile deformation as it passes through the bore during the firing sequence. By placing the lands opposite of the grooves, the bullets are no longer squeezed on opposite sides ensuring the projectile stays uniform instead of squeezing material into the grooves.

What is the best type of rifling used in firearms?

Button-rifled barrels can be extremely accurate; more bench-rest records are held by shooters using guns with button-rifled barrels than by any other type. Button-rifled barrels are very common on modern centerfire and rimfire guns.

Which twist rate is best?

The best barrel twist rate depends on what type of bullet you are shooting. A fast twist rate such as a 1:7” twist barrel will work better with long-range modern bullets where as a shorter twist such as 1:10” or 1:11” twist barrel will work better with shorter bullets.

What is the best twist rate for a 55 grain bullet?

In that case, you’re probably going to want to look for a faster twist rate that stabilizes larger bullets. 1:10 and 1:9 twist barrels, which work just fine with 55 grain projectiles but will also handle heavier 60, 62, and 69 grain bullets.

What is the twist rate of a 556 rifle?

In the 1960’s, when the 5.56×45 and the accompanying AR platform debuted, both rifles had barrels with twist rates of 1:14 inches, or one full rifling twist for every 14 inches of barrel. That’s because at that time the standard choice in 5.56 ammo was a 55 grain FMJ projectile.

What is the best twist size for a pistol barrel?

For that reason, the faster twist barrels—1:8 and 1:7—are best with heavy bullets. 1:8 twist barrels will stabilize bullets up to 80 grains, and 1:7 tubes will actually stabilize heavy, long-for caliber, aerodynamic bullets up to 90 grains.

What is a 1 7 twist on a pistol?

A 1:7 twist means the bullet turns a full 360 degrees every seven inches of barrel. Nine inches of travel for each rotation gives the barrel a 1:9 rifling rate.