The availability of .223 Rem ammunition in different grain weights often revolves around several factors including historical preferences, manufacturing costs, and the intended use of the ammunition. Let's delve into why the 62-grain FMJ version isn't as commonly produced compared to the 55-grain variant:
Historical Precedence and Military Standards
The 55-grain bullet has been a longstanding standard, especially with the initial design of .223 Remington. It gained prominence due to its use in the military, which extensively utilized 55-grain bullets for a variety of applications. This set a trend and a manufacturing standard that many companies adopted and continue to stick with.
Ballistics and Performance
The 55-grain bullet offers a balanced profile of speed and performance. It is generally seen to offer good trajectory and velocity, making it a popular choice for hunting small to medium game and for target shooting. The 62-grain bullet, while offering slightly better wind resistance and stability, does not offer a massively different performance profile for most shooters, which could be a reason why it isn't as popular.
Velocity
55-grain:
-
Muzzle Velocity: Typically ranges from 3,000 to 3,300 feet per second (fps).
-
Velocity at 500 yards: Can be around 1,300 to 1,500 fps.
62-grain:
-
Muzzle Velocity: Generally slightly lower, ranging from 2,800 to 3,100 fps.
-
Velocity at 500 yards: Around 1,200 to 1,400 fps.
Trajectory
55-grain:
-
Trajectory: Flatter trajectory at closer ranges due to higher initial velocity.
-
Drop at 500 yards: Depending on various factors including barrel length and atmospheric conditions, the drop can be around 50 to 60 inches.
62-grain:
-
Trajectory: Might experience a slightly more curved trajectory compared to the 55-grain variant.
-
Drop at 500 yards: Generally experiences more drop compared to 55-grain, potentially around 60 to 72 inches.
Terminal Performance (impact/energy)
55-grain:
-
Muzzle Energy: Ranges between 1,200 and 1,290 foot-pounds (ft-lbs).
-
Energy at 500 yards: Significantly reduced, potentially around 150 to 200 ft-lbs.
62-grain:
-
Muzzle Energy: Slightly higher, generally between 1,250 and 1,340 ft-lbs.
-
Energy at 500 yards: Could be slightly higher than 55-grain, around 200 to 260 ft-lbs.
Stability and Wind Drift
55-grain:
-
Wind Drift: Lighter bullets are generally more affected by wind drift.
-
Stability: Requires a less aggressive twist rate, often stabilized well in 1:12 to 1:9 twist barrels.
62-grain:
-
Wind Drift: Being slightly heavier, it can offer slightly better resistance to wind drift.
-
Stability: Requires a more aggressive twist rate for optimal stabilization, often performing best in barrels with a 1:7 to 1:9 twist rate.
Manufacturing Economics
Producing a diverse range of ammo types involves different costs — from the creation of distinct molds to altering production lines to accommodate different specs. It's economically sensible for manufacturers to stick to producing the more popular and historically prevalent 55-grain FMJ ammunition as it guarantees a steady market demand.
Demand and Supply Dynamics
The law of demand and supply plays a pivotal role here. The 55-grain variant has a higher demand due to its longstanding presence in the market. Companies tend to produce what is in higher demand to ensure sales and profitability.
Barrel Twist Rates
Different firearms are optimized for different bullet weights. Many of the earlier .223 Rem rifles were designed with a 1:12 twist rate, which is optimized for lighter bullets such as the 55-grain. While modern rifles come with a faster twist rate to stabilize heavier bullets, a significant number of rifles in circulation are optimized for the 55-grain bullets, hence the sustained demand for this weight class.
Conclusion
While the 62-grain FMJ .223 Rem ammunition indeed has its audience, especially among those who prefer a bullet with slightly better ballistics in terms of wind resistance and stability, the 55-grain version remains dominant owing to its historical background, balanced performance profile, and economic factors guiding production and demand. It is a situation where tradition meets practicality, steering the market trends consistently over time.
