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.
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.
Is a 1/7 twist AR barrel good?
A common slow twist rate, for example, could be notated as 1:12. A twist rate of 1:12 means that the bullet does one 360 degree rotation per 12 inches of barrel. 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.
What ammo do police use in AR-15?
BTHP TAP (Tactical Action Police) round in 5.56mm (. 223 Remington) has been shown in numerous tests to be one of the most efficient and effective 5.56mm loadings available for the M-16/AR-15 family of weapons.
What’s green tip ammo?
M855 is often called “green tip” ammo for its special color coding (the full metal jacket is painted green at the nose). These 5.56 cartridges push a 62 grain projectile designed with a boat tail, lead core, and a special steel “penetrator” tip.
What’s the barrel twist rate on an AR 15?
The most common barrel twist rates for modern rifles are ratios of 1:7, 1:8 and 1:9. Today the most common rates of rifling in AR-15s are 1:7, 1:8 and 1:9. When Eugene Stoner designed the M16 he originally made things much slower—1 complete turn every 14 inches, with four grooves, to be precise.
What’s the best twist rate for a rifle?
Heavier bullets perform best from barrels rifled at 1:7. Those 75-grain loads and up are very comfortable at this rate. Too much rotation on a light (shorter) bullet and it can suffer out-of-control “overspin” downrange. Those longer heavyweights require more “twist” to initiate the motion and remain stable at distance.
How many degrees does a 1 : 7 twist bullet turn?
The first figure indicates one full rotation of the bullet, followed by the number of barrel-travel inches (in the United States, anyway) required for its completion. A 1:7 twist means the bullet turns a full 360 degrees every seven inches of barrel.
What is the rifling rate of a barrel?
Nine inches of travel for each rotation gives the barrel a 1:9 rifling rate. Some European manufacturers indicate distance in metric units, usually centimeters. Companies routinely report the barrel twist rate information in their documentation and some stamp it onto their barrels. Similar, Not Always Equal