It’s nothing new for a company to introduce a rifle cartridge, tons of them try it and like restaurants 90% fail in the first year. What is exciting is when a round has so much potential in less than a decade it changes the entire rifle game. The 6.5 Creedmoor was one of those rounds. It came to life in 2008 from a little ammo company we know and love called Hornady.
The 6.5 Creedmoor is a rifle round that can be chambered in short action and semi-automatic rifles like the AR 10. It’s a direct competitor to the classic 308 Winchester. The 308 has been in the service of sportsman since the 1950s. It’s also a short action rifle round that is the AR 10’s original caliber. For the longest time, it was the king of full powered short action rifle rounds.
Which is better? We go to science for that.
The 308 Win and it’s military cousin the 7.62 NATO, have long been the choice of military and police tactical shooters. It hits hard and has excellent penetration. It’s great in a semi-auto or bolt action platform. The round was originally designed to be a battle rifle cartridge and not a Sniper rifle cartridge.
The 6.5 Creedmoor was designed for long-range shooting by ballisticians with over 50 years more data and science than the 308 Win. It’s a round loved by 1,000-yard bench rest shooters and has been for a reason.
The 6.5 Creedmoor has considerably less drop, and out to a thousand yard, it outperforms the 308 significantly. At 1,000 yards the 308 on average has in excess of 300 inches of drop and has a velocity of around 1,500 feet per second when loaded with a 150-grain projectile. The 6.5 Creedmoor experiences less than 300 inches of drop and the heaviest rounds are still hitting 1,600 feet per second.
On average the Supersonic range of the 6.5 Creedmoor is further than the 308 Winchester by 200 feet.
Sectional density comes from a calculation that compares a bullet’s diameter and its weight. The higher the sectional density the better the round is. Sectional density is important when it comes to considering a rounds ability to penetrate. This is going to be a consideration for hunters who need to stop a living target.
Sectional density is calculated by dividing the bullet’s weight in pounds by its diameter in inches. So if you took a 308 round and a 6.5 round of the same weight the 6.5 would have a higher sectional density due to its diameter.
For example, a 150 grain 7.62 round has a sectional density of .226
A 150 grain 6.5 mm round has a sectional density of .307.
This means the 6.5 mm round is going to outperform the 308 when it comes to penetration. This is going to be incredibly important when it comes to penetrating an animal.
Ballistic coefficient, or BC, is a measure of how a bullet cuts through the air. Essentially it’s a rating based on how streamlined the bullet is and how it resists air drag. When comparing BC’s the higher the BC the better. A high BC means the round is more streamlined and resists the effects of air drag. A high BC also means a projectile is more resistant to wind drift, maintains a higher velocity.
The higher the BC the flatter the trajectory will be. This means less bullet drop and a more predictable drop pattern. This is invaluable to know when shooting at long ranges and the flatter the trajectory the easier it is to hit a target. Without digging too deep into the science of BC we can show the difference between 308 and 6.5 CM.
Let’s look at Hornady’s Match Loads:
The 308 Win Match 178 grain boat tail hollow point has a BC of.530
The 6.5 CM Match 140-grain boat tail hollow point has a BC of .580
You see this trend throughout a wide variety of loads. When you compare like with like you see the 6.5 always wins in BC.
Rifle and Ammo Selection
The science behind ammunition is fun and as a wanna be ballistician I find it equal parts fascinating and confusing. Now inside of 500 yards you aren't likely to notice much difference between the two rounds unless you are a competition shooter. Even then it’s minimal. The 6.5 Creedmoor has proven to be ballistically the better round. Will that be a major concern for shooters inside 500 yards?
Unlikely. What will affect you is your ability to choose a particular rifle. Rifle choice is one of the most important considerations for any shooter. At this point rifles in 308 are not only more common, but they are significantly cheaper on average. This isn’t always the case, a Remington 700 SPS in 6.5 Creedmoor is about the same price as the same gun in 308.
However, if I wanted an AR 10 in 6.5 Creedmoor I’d have to be willing to spend significantly more money. Also if I was shopping for a budget rifle I’m more likely to find it in 308 than 6.5 Creedmoor.
Luckily, it’s easy to find 6.5 Creedmoor ammo, and even reloading components. When you compare similar quality 308 and 6.5 rounds the prices are quite similar, often within a few cents of each other. The major advantage 308 shooters have is 7.62x51mm NATO rounds. These FMJ loads are for the military but there is plenty of civilian runoff that turns into cheap plinking ammo. There is also international support for the 7.62 NATO which is also for sale on the open market. This drives prices down for plinking ammo significantly.
308 wins the logistic war...for now.
Is the 308 Dead?
This may seem like I'm just bashing the 308 but I'm really not. Realistically the 6.5 Creedmoor is the better round. This doesn’t mean we need to dump 308 in the trash and buy 6.5’s. It just means the firearms world is constantly improving. The 308 Winchester isn’t going anywhere anytime soon.
What say you people of the gun? Are you a 308er who likes to tell 6.5 CM to get off your lawn? Or are you a 6.5 CM fan who wants to leave 308 in a nursing home? Or are you simply a lover of all things that go boom?
Let us know!