To wring out the ammunition and weapons, five-hundred rounds of the
Hornady 110-grain OTM were put through three 6.8 SPC uppers, most of
it rapid-fire.
Starting with the case and primer, they determined that a small rifle primer is
a better choice for 6.8 SPC. Hornady Vice President of Sales and Marketing
Wayne Holt states that a large primer in 6.8 SPC contributes to premature
unlocking of the AR-15 action. Since nobody else made brass with small primer
pockets, Hornady went ahead and tooled up to make it themselves.
Hornady then used their expertise in computer modeling to find the best bullet
design. The result was a 110-grain OTM bullet with a very sharp ogive; it
appears almost as a spire point instead of a rounded curve to the bullet tip.
The bullet was designed for improved terminal performance after passing through
intermediate barriers, such as interior walls or car doors. This bullet is not
designed for pure target-shooting performance; it sacrifices a slight edge in
accuracy to designs like the Sierra MatchKing in favor of increased lethality.
The BC of the new 110-grain OTM is 0.360.
Moving to the powder mixture, 6.8 SPC presents the challenge of limited case
capacity. To achieve maximum velocity in a given pressure envelope, a
slower-burning powder must be used, but doing so can run up against the case
capacity limit. Furthermore, the powder must present a pressure profile such
that enough gas pressure and dwell time are produced to run the various
As a spent case flies from the ejection port, the rifle is still
on-target. Shooters found a compensator helpful in retaining a sight
picture through recoil.
different configurations offered by rifle manufacturers. Besides maximum
pressure, the ammunition must not generate excess bolt thrust, which can cause
weapon failure over time. Hornady is also using a powder formulated for
low-muzzle flash, which is especially important for short-barreled rifles.
The end result is a load designed to work in any 6.8 SPC rifle, from
10-inch full-auto entry carbine to a 16-inch semi-auto for
home-defense, ranch use, or law-enforcement patrol. To verify
function in the wide variety of 6.8 SPC weapons available, Hornady ran
their ammunition through samples of every 6.8 SPC AR-15 upper they
could get their hands on. These uppers differ primarily in gas port
location and diameter, as well as chamber dimensions.
Besides the new 110-grain OTM load, Hornady also offers a load using their
110-grain V-MAX bullet. This bullet is much more frangible than the OTM, and
would make a good choice for small to medium game, or for defense use when
over-penetration is a concern.
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