Why a New Cartridge?

Firearms and Ammunition are a mature technology. What I mean by Mature, is that for the most part, if it can be done, it has been done, and there is very little that can be done to move the technology forward by leaps and bounds. Mature technologies can still be improved but the changes are often subtle, slow, and expensive. Requiring lots of R&D/industry support to be successful. An example of subtle improvements would be tweaking bullet design to increase it’s Ballistic Coefficient, or a new powder additive that reduces copper fouling. Both of these changes improve performance but don’t result in substantive changes in firearms or ammunition.

If you stick around in the hobby or industry for very long you are likely to see old idea’s be reintroduced as new ideas, and of course marketing will say these are “Game Changing”, “Revolutionary” changes in order to get you to spend a buck. The reality is, they are typically slight improvements that the market may or may not see the value in.

Right Idea, Wrong Timing

An example of old ideas being recycled would be the 300 Whisper and the 300 AAC Blackout. The 300 Whisper was introduced as a wildcat cartridge in 1992 by J.D Jones. It is a trademarked and somewhat proprietary cartridge. It is required that all ammunition commercially produced to be accepted by CIP, and thus it became a CIP cartridge, but never became a SAAMI Cartridge. Due to its trademarked status, it is likely companies had to pay royalties to produce ammunition and rifles for this caliber.

300 AAC Blackout with 220gr SMK

300 AAC Blackout was developed in 2009 by Advanced Armament Corporation, this cartridge was submitted and accepted by SAAMI. This SAAMI Acceptance is likely one of the reasons for the cartridges widespread success as major manufacturers were free to make ammunition and rifles using SAAMI Specs. The difference between the 300 Blackout and the 300 Whisper is slight, but it is enough to possibly create some higher then safe pressures when shooting a 300 Blackout in a 300 Whisper chamber. This is due to the tighter throat in a 300 Whisper.

The idea behind the cartridges is identical. Take a 30 Caliber bullet and shoot it subsonic from a M14/M4 platform. The interest was expressed by military customers in 2008-2009 timeframe. As it allowed their operators to gain all the advantages of using a pistol caliber submachine gun, with almost none of the disadvantages (I.E New weapons platform). Unfortunately for SSK Industries who own the trademarked 300 Whisper, their idea was 10 years too early. While I don’t know why SSK Industries didn’t jump on marketing this round to military contractors, AAC did. As a result Remington, which now owns AAC, produces millions of rounds of 300 Blackout a year.

Forum jockeys and keyboard warriors decry the 300 Blackout, citing it’s ballistic similarity to 7.62×39. Why get an AR-15 in 300 Blackout when you can get a AK in 7.62×39? Especially if you never intend to shoot subsonic bullets, or make use of a suppressor. 5.56×45 or 223 Remington, will do everything that a 300 Blackout will do except for shooting heavy for caliber bullets at a subsonic velocity. If you intend to shoot suppressed, and like quite guns, then 300 Blackout is a good option, but if you want a versatile rifle, 7.62×39 or 223 Rem are likely the better choices.

6.5 Creedmoor vs 308 Win

New cartridges that are introduced typically fill some sort of specific need. They are not designed to specifically replace all other cartridges which may have come before. This is true of the 6.5 Creedmoor which was developed as wildcat to edge out the competition at high power rifle events (Hence the Creedmoor name).

6.5mm or .264 caliber has been popular in Europe for a long time, being used in military cartridges like the 6.5X55 Swede. In the United States .308 Caliber has long reigned king for high power competitions. Again the origins of this can be traced back to the military use of 30-40 Krag, 30-06 Springfield, and 308 Win.

6.5 Creedmoor, is based off the 30 Thompson Center (TC), which is a shortened 308 Win case. From it’s conception it was designed to be a long range cartridge capable of shooting high B.C. Bullets from a short action rifle. While not alone in the market of 6.5 cartridges designed for long range shooting (6.5-284 Norma), it is by far the most popular due to its acceptance as a SAAMI Cartridge, low recoil, and it’s versatility as both a hunting and target cartridge.

Does the 6.5 Creedmoor out perform 308 Winchester? Well, it depends on what metric you use.

The 6.5 Creedmoor has a higher muzzle velocity but a slightly lower G1 Ballistic Coefficient value. The higher muzzle velocity results in more favorable “flatter” shooting trajectory for the 6.5 Creedmoor compared to the 308 Win. Drop is about 7% less for the 6.5 Creedmoor.
308 Win has a 35gr heavier bullet then the 6.5 Creedmoor. This results in high muzzle energy and that energy is carried through the bullet’s travel. How much higher? Depends on the distance but at the muzzle it is 250ft/lbs, and at 1000 yards it is reduced to roughly 100ft/lbs. At 1000 yards the 308 Win carries ~12.5% more energy than the 6.5 Creedmoor. This seems significant but isn’t, the target won’t know the difference.

When I look at the ballistics for a 6.5 Creedmoor versus a 308 Winchester, I see two cartridges that perform very similarly with a slight advantage to the 6.5 Creedmoor. What is not represented in either chart is the recoil of the rifle.

Shooters Calc is a great website offering a Recoil Calc Tool which makes it easy to compare the recoil on different cartridges. Note: These numbers change if you have a muzzle break or recoil pad.

The recoil difference between the 6.5 Creedmoor, and the 308 Win, is what I believe tilts the scale in favor of the 6.5 Creedmoor. We are all sensitive to recoil, and people who are used to shooting 308 Win, are used to the recoil of their rifle. Put in their hands a 6.5 Creedmoor that has slightly less recoil and they will notice the difference. In total it’s about 22% less recoil for a 6.5 Creedmoor when compared to a 308 Win, if the rifles weigh the same.

None of these differences are night and day. They are typically small improvements over existing technology. Differences that may make the differences between taking home gold or silver in a shooting match, but will likely not make the difference between a full or empty freezer.

Taking home gold versus silver is what the 6.5 Creedmoor was developed for. It is a cartridge that was designed to be slightly better than the 308 Win in order to edge out the competition. These design improvements carried over into making a successful hunting cartridge. Hornady submitted the cartridge to SAAMI and once codified marketed it as the next big thing. As a result of its popularity the 6.5 Creedmoor is likely here to stay.

Do We Really Need Another 30 Caliber Magnum Round?

Hornady recently introduced the 300 PRC (Precision Rifle Cartridge. Based off the 375 Ruger necked down to .308 Caliber, Hornady has promised it to be the “Game Changing” cartridge for long range shooting. There are many .308 caliber magnum rounds. Such as 300 Win Mag, 300 RUM, 30 Nosler, 300 Weatherby Magnum, and 300 H&H. So what does the 300 PRC offer that these other calibers don’t.

With this cartridge is it all about the cartridge dimensions. In order to understand these dimensions I charted them out using excel.

A simple table can help compare the characteristics of several cartridge and help understand the pertinent differences.

There are a few things that jump out immediately when comparing SAAMI 30 Caliber magnum cartridges. The first is the Case Head Diameter. They are near identical. This is important as it shows that these cartridges will all fit within “Magnum” type actions. Cartridges such as the 300 Norma Mag or 300-338 Lapua, which are not SAAMI cartridges, have much larger case heads and require larger actions, making the rifles more expensive.

The second thing that jumps out is the SAAMI Maximum Average Pressure (MAP) for each cartridge. This standard pressure a manufacturer will load a cartridge too. The 300 H&H and the 300 Win Mag are both lower. Since more pressure is going to result in more velocity, these two cartridges will not be able to produce the same velocity as their other 30 Cal magnum cousins. Now, can you as an individual load hotter and get the same performance? Yes, but you also take your own safety into your own hands. This comparison is assuming we are comparing off the shelf ammunition, not your hot rodded loads.

The last thing that is of note to me is the Max Cartridge Overall Length. This dimensions is the maximum length a cartridge may be loaded to. Having a long COAL has two possible advantages, the 1st being that it results in more usable case capacity, which allows for more powder to be stuck behind the bullet. The purpose of this is to get higher velocities. The second is it allows a cartridge to utilize low drag bullets which have long secant ogives. Competitive shooters love high B.C. bullets because they hold on to their velocity longer.

The remaining four SAAMI 30 Cal Magnum Cartridges, comparing Usable Case Capacity and Max Ogive Length.

If we look at the four remaining cartridges, we can see that the 300 RUM is the king of the usable case capacity. When Remington introduced the RUM family of cartridges the design intent was to maximize the amount of powder they could stick behind a bullet while utilizing a magnum action. We can see they accomplished their task, but the weakness for the 300 RUM is that the max length of the ogive is limited to 0.750in. So while they can launch a 220gr bullet at high velocities, they can’t utilize the high B.C. low drag bullet designs.

If we look at the remaining cartridges, we see they are all comparable in usable case volume to the 300 PRC, the biggest difference is the ogive length. The 300 PRC allows for an ogive that is over .330in longer then the next closest rival, the 30 Nosler.

So does the 300PRC have an advantage over other 30 Caliber Magnum Cartridges on the market? Yes, it is specifically designed to shoot long nose, low B.C. bullets off the shelf with no modifications, and we can see that by examining the dimensions alone. This is not true of any of the other cartridges listed. All off them would require some modification to get the same loads to work, and then the shooter would be limited to shooting their own handloads.

For kicks and giggles let’s take a look at 300 RUM verses a 300 PRC.

The PRC can make use of the 230gr SMK which has a long secant nose. This gives it a an extremely high B.C value of .800. Given it is a heavier bullet, and there isn’t as much usable case capacity as in the RUM, the bullet velocity is 2700fps.

The 300 RUM however can’t make use of the 230gr bullet and is limited to the 220gr SMK which has a much blunter ogive and a much lower B.C. of .629. The larger usable case capacity and the 10gr light bullet helps to accelerate the bullet to 2850fps.

We can see the trajectories are very similar between the 300 RUM and the 300PRC. Despite the differences in the muzzle velocities, bullet weights, and the B.C. There is a slight advantage to the 300 RUM.
Even though the trajectories are very similar the 300 PRC with it’s ability to shoot high B.C bullets is clearly a superior cartridge. The higher velocity will result in less wind drift then the 300 RUM at longer ranges.

The 300 RUM is known to have a heavy recoil, and is unpleasant to shoot without a muzzle break.

Compare that recoil energy to the 6.5 Creedmoor, ouch!
The recoil energy for the 300 PRC is 20% lower than the 300 RUM, with near identical bullet drop, and higher bullet velocity down range…all while requiring less powder. To be still, this rifle would still be fairly unpleasant to shoot without a break.

The 300 PRC commercializes what custom gunsmiths and hobby tinkerers have been doing for a long time. It provides a rifle capable of shooting high B.C. Bullets in 30 Caliber off the shelf with the ammunition to go with it. It lowers the cost of entry for people who want to get into long range shooting, without learning how to reload or paying the extra for custom rifle. Despite what marketing department might claim (Hornady has a top tier marketing department), these are small changes, and to their credit, it is a better cartridge then what was currently recognized by SAAMI.

Wrapping it Up

When I look at new cartridges, especially ones that have been added to SAAMI, I always ask myself why did a company spend the time, effort and money to get this cartridge SAAMI recognized. It’s not a cheap or easy thing to do. Which is why the vast majority of cartridges, even ones that are CIP recognized, are not SAAMI recognized. So before decrying it as “Just a money grab” take some time look at it’s merits. Someone thought it was worth the investment.

As I stated when I began this article, firearms and ammunition are a mature technology. Despite marketing claims of revolutionary improvements, almost everything new that is introduced are small gains. Little tweaks or changes that improve on existing cartridges a little. Over time these small changes add up. If someone was shooting long distance with a 300 H&H, and was suddenly introduced to the 300 PRC, they would likely be amazed by it, not aware that took the 300 Win Mag, the 300 RUM, advances in bullet design, and lots of failed cartridges to get a cartridge like the 300 PRC. To us, who have literally 100’s of cartridges to choose from, it is hard to keep track of the subtle advantages of a new cartridge without a closer look.

Hopefully this write up has given a fair and honest evaluation of the cartridges. The prompt for this write up came from various discussions with friends over 300 PRC, 6.5 Creedmoor, and the 300 Blackout. If you like to see more of these in depth look at various cartridges, and what their purpose is or how they stack up to other cartridges please let me know.