The US Army’s Ballistic Research Laboratory measured a ballistic coefficient (G7 BC) of 0.151 and form factor (G7 i) of 1.172 for the SS109/M855 ball projectile.
Does barrel length affect bullet drop?
Barrel length doesn’t affect the mechanical accuracy of your rifle. At least not enough to worry about. What’s actually happening is that the ballistic curve of the bullet becomes flatter as velocity increases. In other words, you need less sight adjustment or holdover in order to make a shot.
What length of barrel is best for AR 15?
20″ barrels provide the most consistent performance across the widest variety of loadings. There are plenty of modern specialized loads “optimized” for use in a 16″ barrel, but the 20″ length will still do things better. Aside from the benefits of velocity, the long 20″ barrel gives a balance benefit to marksmen.
How much does barrel length affect trajectory?
First, velocity. Longer barrels generate higher velocity because the propellant burns more completely. However, there are diminishing returns with extra-long barrels, depending on cartridge, caliber and propellant. It is often said we can expect a velocity change of about 20 to 25 fps per inch of barrel loss.
How accurate is M855?
During my 26 years in the Army, the average accuracy from M855 Green Tip I observed averaged between 2 and 3.5 MOA. So, when the military said the new EPR round was “better” (but not by how much) that did not instill much desire in me to give M855A1 a serious look.
Is M855 Full Metal Jacket?
The 62 grain 5.56 bullet is a Full Metal Jacket (FMJ) tipped with green to indicate the steel insert inside. Muzzle velocity is 3,060 fps (feet per second) and the muzzle energy is 1,289 ft. -lbs.
How much does a 556 drop at 300 yards?
The bullet drop on the 5.56 over a range of 500 yards is 54.2 inches. The start sees the bullet drop a little to about 1.75 inches and maintains this height up to 300 yards where it drops a further 8.3 inches. At 400 yards out, the drop is 24.56 with the 500-yard mark, making for the 54.2 inches drop.
What can M855 penetrate?
Although it’s not an armor-piercing round, the EPR can penetrate 3/8 inch-thick mild steel at distances approaching 400 meters (based on the range at which 50 percent of the rounds can pass through the barrier). The M855 only penetrates this material out to approximately 160 meters.
Is M855 inaccurate?
What is the muzzle velocity of a M855 bullet?
M855 bullets traveling below 2,500 fps when impacting a target will not produce a lethal wound channel. There have been a number of studies demonstrating the barrel external temperature gradient as a function of barrel length in addition to numerous studies of muzzle velocity as a function of length.
What is the M855 round used for?
At the time, Russian helmets were commonplace among opposing forces, who wore surplus armor and protection. Due to the increased performance, stopping power, and penetration capabilities, the M855 round serves as the standard 5.56x45mm ammunition for the United States Military and countless other NATO forces since approximately 1982.
How many different types of M855 ammo are there?
Cutaways of 5.56 ammo. Three variants of M855 at the left, followed by two variants of the new M855A1, followed by a much more rare M995 Tungsten AP round. Let’s get down to the nitty-gritty numbers of the M855 round.
What makes the M855 different from the M193?
Unlike the M193, the M855 is designed with a boat tail, lead core, and a steel penetrator tip designed to pierce modern body armor with relative ease. Why is the penetrator tip so unique?
