Sneak Preview: Hornady 75 grain 5.56 NATO Superformance
Sneak Preview
Hornady 75 grain 5.56 NATO Superformance
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Hornady’s newest line of ammunition in 223 Remington/5.56mm NATO, “Superformance”, is now shipping. Of particular interest to AR-15 shooters is their 75 grain 5.56 NATO Superformance load. Hornady claims a velocity of 2920 fps for this load from a "20 inch NATO-spec test barrel."
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From Hornady's website.
The 5.56 NATO Superformance load is topped with the “T1” 75 grain BTHP projectile. There is a slight taper crimp at the case mouth and no case-mouth sealant.
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Naturally this load is charged with one of the new, “highly progressive” Superformance powders. According to Hornady, the Superformance propellants “provide a longer duration/application of peak pressure in the pressure time curve that occurs within the barrel. In other words, both Superformance and standard propellants provide an equally powerful 'push' applied to the base of the bullet, but with Superformance propellants, the 'push' is applied for a longer period of time.”
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From Hornady’s website.
The lot of 5.56 NATO Superformance ammunition that I evaluated is loaded in Lake City 09 brass. The primer pockets are crimped and sealed.
Chronographing of the 75 grain 5.56 NATO Superformance ammunition was conducted using an Oehler 35-P chronograph with “proof screen” technology. All velocities listed below are muzzle velocities as calculated from the instrumental velocities using Oehler’s Ballistic Explorer software program. All strings of fire consisted of 10 rounds each. Data was obtained from a Colt 20” M16A2 barrel.
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Each round was single-loaded and cycled into the chamber from a magazine fitted with a single-load follower. The bolt locked-back after each shot allowing the chamber to cool in between each shot. This technique was used to mitigate the possible influence of “chamber-soak” on velocity data. Each new shot was fired in a consistent manner after hitting the bolt release. Atmospheric conditions were monitored and recorded using a Kestrel 4000 Pocket Weather Tracker.
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Atmospheric conditions:
Temperature: 58 degrees F.
Humidity: 32%
Barometric pressure: 29.65 inches of Hg
Elevation: 950 feet above sea level
For comparison, I fired the Superformance load back-to-back with Hornady’s 75 grain 5.56 NATO TAP T2 and 75 grain 223 Remington TAP FPD. The chronograph data is shown in the table below.
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There were no manifest over-pressure signs on the case-heads of the fired Superformance rounds.
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An accuracy Snapshot of the 5.56 NATO Superformance load was obtained from a distance of 100 yards shooting from my bench-rest set-up. The test vehicle was a chrome-lined, NATO chambered 20” Colt HBAR with a 1:7” twist. The barrel was free-floated. The free-float handguard of the rifle rested in a Sinclair Windage Benchrest, while the stock of the rifle rested in a Protektor bunny-ear rear bag. Sighting was accomplished via a Leupold VARI-X III set at 25X magnification and adjusted to be parallax-free at 100 yards. A mirage shade was attached to the objective-bell of the scope. Wind conditions on the shooting range were continuously monitored using a Wind Probe.
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A quick 10-shot control group fired from the above set-up using match-grade hand-loads had an extreme spread of 1.2”.
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The 10-shot group of the 75 grain 5.56 NATO Superformance load had an extreme spread of 3.4” and a mean radius of 1.16”.
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For the Internet Commandos in our viewing audience tonight, here’s a pic of a cherry picked, 3-shot group of the 5.56 NATO Superformance load.http://www.ar15.com/images/smilies/icon_smile_big.gif The group has an extreme spread of 1.263”.
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For comparison, I also fired a 10-shot group of Hornady’s new .223 Remington 53 grain Superformance load. This load uses a brand new bullet from Hornady, the 53 grain V-MAX. The ogive of the bullet is tailored for .223 Remington chambers. This load produced a sizzling muzzle velocity of 3285 fps when chronographed from a 20” Colt M16A2 barrel.
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The 53 grain V-MAX is shown on the left compared to a 52 grain A-MAX on the right.
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The 10-shot group of the 53 grain Superforance load had an extreme spread of 1.213” with a mean radius of 0.458”. It will be interesting to see how this load performs out of my .223 Remington chambered Krieger barreled AR-15.
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To be continued . . .