By John Stewart, chief gunsmith of Kiote Rifles
In the spring of this year, several media outlets reported that SOCOM command had chosen the 6.5 Creedmoor for it’s “intermediate” caliber of choice. I read as many of the articles as I could find and even called up a close SF SgtMaj friend of mine to ask him about what was going on. His response was something to the effect of “No hit, no idea. That’s some crazy shit.”. My sentiments exactly.
Upon further discovery, it seems that someone with a heavy enough collar decided to put 6.5 Creedmoor up against the .260 Remington and the .308 Winchester for the purposes of their study. Unfortunately, no one I know is privy to the exact specifications of that study or the actual data that resulted from it. So, as is usual for me, I approached it from an analytical perspective to find out if, in fact, it was the best choice they could have made.
Here’s the approach I took:
• Compare the exterior ballistics of the 6.5CM, .260 Rem, .308Win, .300 Win Mag, .300 Norma Magnum & the .338 Lapua Magnum;
• Compartmentalize the results of the 6.5CM, 260 Rem & .308 Win for direct comparison;
• Use the three larger calibers for comparison in long-range testing;
• Use a projectile type most commonly found in the U.S. arsenal;
• Compile data derived from the average velocity, barrel length, and twist rate for each caliber;
• Derive results from there (charts & graphs at end of article).
Here’s a list of the parameters used for each caliber:
• 6.5CM: 142gr SMK pushing 2700fps with a BC of 0.510 G1, 1:8”, 26” OAL
• 260 Rem: 142gr SMK pushing 2850fps with a BC of 0.510 G1, 1:8”, 26” OAL
• 308 Win: 175gr SMK pushing 2700fps with a BC of 0.475 G1, 1:10”, 24” OAL
• 300WM: 180gr SMK pushing 2900fps with a BC of 0.482 G1, 1:10”, 26” OAL
• 300NM: 225gr BTHP pushing 3000fps with a BC of 0.670 G1, 1:10”, 26” OAL
• 338LM: 250gr SMK pushing 2800fpsh with a BC of 0.614 G1, 1:9”, 26” OAL
* yes, we know that these are boat tail projectiles and therefore should probably use the G7 drag model, but all reports indicate that the G1 model was used for the test in question.
This is what we found in our study of the three calibers examined by the U.S. Army:
• Comparing the 6.5CM, .260 & .308, it’s clear that the .260 has the better performance in terms of both drop and effective range (effective range for the purposes of this study is defined as the distance at which the projectile goes subsonic at sea level with an ambient temp of 80F, relative humidity of 25% and a barometric pressure of 29.92 inHg).
• The .260, even when using the last choice of projectiles from the bigger manufacturers, beat out the 6.5CM by 200 yards (reaching 1500 yards before going subsonic) and the .308 by 500 yards.
• Using 600 yards as the benchmark for the long end of an intermediate range, the .260 drops 3.25 MOA (11) less than the 6.5CM (14.25) and 3.75 less than the .308 (14.75).
• As it pertains to kinetic energy, the .260 blows both of the other calibers out of the water at 600 yards. The .260 has 1302 ft-lbs; whereas the 6.5CM and .308 have 952 ft-lbs & 1093 ft-lbs, respectively.
Conclusion: the .260 is the obvious winner in terms of both ballistics and killing power.
It’s been a few years since the Army decided to switch from the .308 to the .300 Win Mag (from the M24 to the M2010 ESR). More recently, the Marine Corps has fielded their version of the .300 Win Mag, transitioning from the M40A6 to the Mk 13. So while we were at it, we decided to look at the hard facts of those two calibers. The results are as follows:
• The .300 WM does, in fact, despite its mechanical faults, have a better ballistic range than the 308 by about 200 yards. The .300 WM goes subsonic at 1200 yards vs the 1000 yards of the 308.
• When it comes to Kinetic Energy, the Win Mag only offers a slightly higher rating (64 ft-lbs) than the 308 at 1200 yards but they rapidly approach nearly identical numbers with each subsequent 100 yards thereafter.
Conclusion: We had to choke this one down just because the Win Mag is obsolete in our minds when it comes to precision shooting. However, it is clearly the winner in this challenge – when considering what’s currently available to our military shooters.
In the last couple of years, the 300 Norma Magnum has been gaining more and more attention as a solution to solve everything that ails the military shooter. Sure, it’s by no means considered an “intermediate” caliber. But if you had to choose one caliber to do everything from zero to 1.5 miles, its your huckleberry. In the last year, I’ve made a few of them for exhibits at SHOT Show, personal use and coming soon, our exhibit at the Modern Day Marine Expo at MCB Quantico.
For those of you unfamiliar with the .300 Norma, here are a few quick facts:
• Shortened .338 Lapua case
• Necked down to a .308 caliber throat
• Wide variety of projectile options
• By virtue of its design, shorter OAL than the Lapua while maintaining superior performance
• Less recoil than the Lapua – given that both rifles weigh a minimum of 12 pounds and each round is loaded with the minimum powder charge, the Norma produces 30.5 ft-lbs at a rate of 12.8 ft/s while the Lapua produces 33.3 ft-lbs at a rate of 13.4 ft/s according to JBM Ballistics.
But the real proof is in the pudding. Here are the numbers for the Norma vs the Lapua (and I’ll even throw in the Win Mag numbers for effect) at 1000, 1500 & 2000 yards. The numbers are listed as drop(moa)/KE for each respective distance.
• .300 Win Mag: -30.25/669, -68.25/368, & -128.25/266
• .300 Norma Mag: -23/1506, -46/820 & -81.75/521
• .338 Lapua Mag: -28/1261, -58.75/686, & -105/481
Conclusion: if you want just one rifle to cover the entire gamut of precision shooting, the 300 Norma Magnum is the obvious choice. While it may be a little overkill for hunting anything smaller than an elk at distances less than 600 yards, it is the winner of these 3 calibers.
So where does that leave us? Well, according to the U.S. Army’s study, it looks like you and I as tax payers are in for another long ride on the big green weenie, just like the $5 million dollar UCP camo fiasco. Hopefully, it doesn’t last that long or cost that much. But the wheels of the government turn slowly. So grab your lube and let’s hope that the powers that be recognize their mistake quickly.
As promised, here are screenshots of the charts and graphs developed from our study. It’s interesting to note that the .260 and .300 Norma have almost identical curves despite the obvious nature of the .260 to drop quicker than the Norma.