Hornady Superformance 6.5 Creedmoor 129 Grain SST

Hornady explicitly states that Superformance is safely within SAAMI pressure guidelines and that gas-operated firearms are safe to use with it. However, Hornady also notes from their testing that “some systems work far better than others” — meaning cycling reliability varies by platform. The load is safe from a pressure standpoint, but some semi-automatic actions may not cycle reliably with Superformance’s specific powder burn rate. Test at least one box in your rifle before hunting season.

The 130 fps advantage (2,950 vs 2,820 fps for Fiocchi Hyperformance SST) produces real but modest trajectory improvements — approximately 2 fewer inches of drop at 300 yards and slightly more retained energy. For hunting inside 250 yards, the difference is essentially irrelevant. For 300–400 yard shots in open country, the flatter trajectory is a genuine practical advantage that reduces holdover estimation error. Whether it’s worth $8/box over Fiocchi’s SST load depends on the distance range you actually hunt.

The InterLock ring is a raised internal ring machined into the copper jacket that embeds into the lead core during manufacturing. Unlike a chemically bonded bullet where core and jacket are fused, the InterLock uses mechanical interlocking — the ring physically prevents the core from sliding forward out of the jacket during expansion. This provides reliable weight retention (typically 65–75%) without the cost premium of fully bonded construction. On elk-sized game, the InterLock’s retention is sufficient for broadside shots; for difficult angles, fully bonded options like AccuBond or Terminal Ascent provide a larger safety margin.

For elk, the Precision Hunter 143 gr ELD-X is the stronger choice in most situations. The ELD-X’s BC of 0.623 far exceeds the SST’s ~0.527, providing better long-range performance. The ELD-X’s dual expansion mechanism (50–60% retention at close range, 85–90% at long range) is specifically engineered for consistent elk performance across all distances. The Superformance SST is adequate for elk inside 250 yards with good shot placement, but the ELD-X’s engineering is more specifically optimized for the task. The Superformance SST is the better choice when velocity and flat trajectory for deer-size game is the priority.