Creedmoor 6mm : The Ideal Long-Range Cartridge? | Shooting Illustrated

The sport of long-range shooting is always evolving. For many years .30-caliber cartridges dominated.

Then along came the 6.5 mm cartridges and they took over, but there is a new contender for the throne with the emergence of the 6mm Creedmoor and other .243-caliber cartridges for long-range work.

The only commercial cartridge in that bullet diameter that has seen much use with precision long-range shooting is the .243 Win. and even that is minimal.

As one PRS competitor told me, “I don’t know why exactly, but I just don’t see that many top-level guys shooting a .243 [Win.].”

As exhibit one, I offer that Ruger initially offered the .243 Win. in its Precision Rifle, but it’s no longer listed. The reason? Lack of sales.

Of course, there are some technical issues impeding the use of the .243 Win. for long range, but in the end it’s a “tail wagging the dog” kind of thing.

The main problem with the .243 Win. is that it has been promoted as a hunting cartridge. Even as it started to gain a bit of popularity with the long-range shooters, most manufacturers decided to take a “wait and see” approach rather than be an industry leader.

None of the big-name ammo makers were willing to load and market high-ballistic-coefficient match bullets for the cartridge. So, we saw the rise of other 6 mm cartridges.

With the increasing popularity of 6mm long-range cartridges it was inevitable that somebody was going to make an honest cartridge out of one of them.

It was probably inevitable, too, that it would be Hornady. This company is still small and nimble enough to introduce new cartridges regularly.

As a result it is the industry leader in cartridge innovation.

As expected, Hornady stuck with its franchise and introduced the 6mm Creedmoor, based on the 6.5 Creedmoor case necked down to take a .243 bullet.

This cartridge was created by a buddy of mine. John Snow is the shooting editor for a popular gun magazine who is also a PRS competitor.

He was kicking around the idea of a 6mm cartridge for a new rifle build with his friends at Hornady and they decided to neck down the 6.5 Creedmoor to 6mm Creedmoor.

Snow had a rifle built, started writing about it and the cartridge gained in popularity with long-range shooters until Hornady saw an opportunity to take it mainstream and went for it.

From my own perspective, I am writing a new book on gunsmithing that will have a big section on building precision rifles. I built several rifles during the process and perhaps the best of the litter is chambered in 6mm Creedmoor.

When I ordered all the parts it was still a wildcat cartridge. By the time I had them all fitted together, Hornady had validated the cartridge and introduced factory ammo to the market soon after.

I had heard rumors and whispers that was going to happen, so I contacted Hornady and obtained a reamer drawing to send to Dave Manson to make a chamber reamer for me. What I thought would be a uniquely different rifle is now mainstream, but that’s fine with me. I can find ammo, brass and bullets easily.

I have no doubt that this year will see a huge number of rifle makers offering the 6mm Creedmoor, but to my knowledge Ruger got there first with its new Ruger Precision Rifle (RPR) in 6mm Creedmoor.

I have one of the Rugers on loan and the first time I shot it was also the first time I had tried the new Hornady 108-grain ELD Match ammunition. As of this writing, it is the only factory load available for the 6 mm Creedmoor.

I shot the ammo first in my custom rifle following the standard Shooting Illustrated accuracy-testing protocol of five, five-shot groups at 100 yards. I didn’t tally the results then, but what I saw through the spotting scope pleased me.

A little later I sat down at the bench to shoot the new Ruger RPR with the same Hornady ammo. As I fired the groups, what I was seeing through the scope was a bit disconcerting. Would this affordable precision rifle outshoot my baby?

I ordered the best parts Brownells offers for this rifle and I spent hours making sure that every single part was fitted with exact precision. It would be embarrassing to have an off-the-shelf rifle outshoot it.

After I finished the last group, one of my buddies got on the spotting scope and started to heckle me. So, I pulled the targets and measured them with a machinist scale.

The first time out of the gate with the new Hornady 6mm Creedmoor 108-grain ELD Match ammo, my Brownells rifle averaged .6 inches while the Ruger averaged .77 inches. It’s less than .2 of an inch difference, but in the precision shooting world that is enough.

What that tells me is that this is an accurate cartridge

It also tells me that Ruger is going to sell a lot of these rifles. I have worked with more than half a dozen RPR rifles in four different chamberings and every single one has been a great shooter.

The first one I tried shot so well that I sent Ruger a check. I hardly needed another 6.5 Creedmoor rifle, but it was too good of a shooter to send it back to Ruger.

With a little tweaking this new 6mm Creedmoor RPR is going to approach being a .5-MOA rifle and it’s going to be hard to send back as well. (You see, this is why I’ll die broke.)

Why the 6mm Creedmoor over the 6.5?

Simple: speed. Sure, the lower recoil is a benefit when you are a competitive shooter and/or trying to spot your own hits, but terminal ballistics improve with speed.

If the bullet is flying faster it has less time for gravity to act on it

The acceleration of gravity causes a bullet to drop to the earth at a rate of 32 fps. So, the longer it’s in flight, the faster it is dropping and the steeper the trajectory curve becomes.

With a sharper trajectory curve from a faster bullet, the margin of error becomes a little larger at any given distance.

On the Hornady website, the 108-grain 6mm Creedmoor is 250 fps faster than its 140-grain 6.5 Creedmoor load. Velocity varies from rifle to rifle and in the real world is often different.

I went to my database of guns and ammo I have tested and calculated an average of 19 strings using several varieties of 6.5 Creedmoor 140-grain factory ammo.

The data includes several factory-ammo products and a bunch of different rifles and encompassing hundreds of measured velocities. The average muzzle velocity is 2,658 fps.

Of course, the factory load database is much smaller for the 6mm Creedmoor, but from the RPR the Hornady 108-grain load averaged 2,944 fps.

From the longer 27-inch barrel on my custom rifle the average velocity is 3,067 fps. That gives an average of the two of 3,005.5 fps. When we subtract the average 6.5 velocity we see a difference of 347 fps, which is not insignificant.

That means the 6mm Creedmoor is traveling more than 100 yards per second faster than the 6.5 bullet when it leaves the muzzle. The 6.5 travels 721 yards in its first second of flight while the 6mm covers 773 yards.

If the ballistic coefficient matched, the 6mm would cover 804 yards in the first second.

Lähde: Shooting Illustrated | 6mm Creedmoor: The Ideal Long-Range Cartridge?

Kategoria(t): Riistanhoito. Lisää kestolinkki kirjanmerkkeihisi.

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