November 24th, 2009
Hornady recently announced its new line of Superformance Hunting Ammo. Loaded with GMX solid bullets and SST jacketed bullets, the new ammo is faster than conventional hunting ammunition. Hornady claims that, “across the board”, Superformance ammo is 100-200 fps faster than other factory hunting ammo with similar bullet weights.
We had a lengthy discussion yesterday with Dave Emary, Hornady’s Senior Ballistician. Dave shared some of the secrets of the new Superperformance ammo, and explained how Hornady is achieving such high velocities. The key, as we suspected, is that Hornady is using new propellants — powders that are not yet available for sale. These new propellants are BALL POWDERS custom-made to Hornady’s specs. Hornady actually commissioned multiple new spherical formulations, in various speed ranges. Then Hornady blends these ball powders to suit particular cartridges and loads. So, each type of Superformance ammo (e.g. 243 Win with 95gr SST and 300 Win Mag with 165gr GMX) represents a custom blend of the new ball propellants of various burn ranges. Hornady tailors the powder blend to achieve maximum velocity, accuracy, and low temp sensitivity for each load.
Hornady is NOT using Alliant’s Reloder 17. However, in some respects, Hornady’s new ball powders behave like Reloder 17 — by “flattening the right side of the pressure curve”. Rather than hitting a high peak pressure and then dropping off dramatically in energy, Reloder 17 sustains high pressure behind the heel of the bullet for a longer in-barrel time. Hornady’s new powders do the same thing — they deliver high energy behind the bullet for more milliseconds as the bullet travels down the bore. This is the main reason Superformance ammo delivers high velocity — the new powders are maintaining higher energy levels for a longer period of time. Additionally, being ball powders that pack tightly, the new propellants can be loaded to a high density in the case — an advantage with medium-sized cartridges such as the 6.5 Creedmoor.
Here is how Hornady has achieved high velocities with its new Superformance ammunition:
1) Superformance ammo uses advanced new Ball Powders (not yet for sale).
2) The powders are BLENDED, with different “recipes” for different cartridges.
3) The new powders maintain high-energy longer in barrel (like Reloder 17).
4) The new powders burn almost completely, reducing ejecta, for less exit pressure, and less felt recoil.
5) Superformance ball propellants pack very densely, so more grains of powder can fit inside a case, compared to typical extruded stick powders. |
High Progressivity Powders
In addition to high sustained energy, Emary noted, the new propellants exhibit very high “progressivity”. What this means, in practical terms, is that the new propellants achieve almost 100% burn by the end of the cycle. So, virtually all of the mass of the powder has changed to gas by the time the bullet exits the muzzle. As a result, Emary explained “with Superformance propellants you have less ejecta leaving the muzzle. With some other extruded powders, you’ll get unburned or partly burned sticks leaving the muzzle”. Why does that matter? Dave explains there are a couple major benefits to high progressivity. First, you get “every last ounce of energy” out of each powder kernel. Second, because less unburned ejecta is driven out the barrel, the amount of recoil is reduced, particularly for the large magnum cases.
Dave explains: “In the past, small arms performance has been limited by the powder’s ability to completely burn by the time the bullet exits the muzzle. To attempt to get higher performance, high charge weights of a slow burning powder were used to attempt to maximize muzzle velocity. Powders were not progressive enough to allow these heavy charges of slow powder to be completely burned by the time the bullet left the muzzle, especially with lighter-weight bullets. The end result was very modest increases in velocity with heavy recoil and many times unacceptable accuracy. Superformance powders solve this problem because of their ability to completely burn by bullet muzzle exit…. This results in a much higher percentage of the available powder energy being transferred to the projectile, rather than being blown out the end of the barrel as unburned powder[.]”
In practical terms, Emary stated, the high energy and high progressivity of the new propellants permit many cartridges to deliver “real-world” performance equaling that of larger cartridges loaded with conventional powders. For example, according to Dave, “the 6.5 Creedmoor is performing on a par with a Rem .260.” Dave cited the example of his own 6.5 Creedmoor hunting rifle: “It shoots as flat as a .260 and the accuracy is as good or better.”
Dave has authored a detailed report that shows how 30-06 Superformance ammo can match the velocities of Hornady’s “light magnum” 30-06 ammo loaded with conventional powders. The Superformance 30-06 achieved similar velocities, with equivalent peak pressures, while using 6 grains less powder. This is illlustrated in the graph below.
Dave’s report states: “[The chart] shows a comparison of Chamber Pressure vs. Time for Custom, Superformance and Light Magnum ammunition in 30-06 loaded with a 150 gr SST bullet. As can be seen from the graph, all loads produced approximately the same pressure but have widely different charge weights and velocity performance. There is considerably more area under the curve for both Superformance and Light Magnum. This is where the increase in performance comes from. One detail to note is that the Superformance chamber pressure has dropped to at or below that of the Custom ammunition by the time the bullet exits the muzzle. This shows the highly progressive burning characteristics of the powder and its ability to completely burn. As noted above, the charge weights which go along with the different loads and the performance achieved with them are quite different. Custom is loaded with 58.5 grs of powder, Superformance 61.0 grs and Light Magnum 67.0 grs. Superformance ammunition produces significantly higher velocities than Custom with only a small amount more powder and the same velocity as Light Magnum with significantly less powder.”
Superformance Ammo for Match Shooters May Be Next
Right now Hornady is marketing its Superformance line as hunting ammunition only. However, Hornady recognizes that the new propellant technology could benefit match shooters as well. Dave told us that Hornady has begun development of a 6.5 Creedmoor Superformance round using the 140gr A-Max bullet.
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