Description

Winchester Super-X Subsonic Expanding .300 AAC Blackout 200gr CPHP — 320 Rounds

The Winchester Super-X 300 Blackout is the expanding subsonic load in the .300 AAC Blackout category.

A 200-grain Copper Plated Hollow Point at 1,060 fps and 499 ft-lbs, engineered to expand reliably at subsonic velocities where conventional hollow points often fail to open.

At $1.56 per round for 320 rounds, the Winchester Super-X 300 Blackout is the conventional HP approach to subsonic .300 BLK terminal performance — contrasting with the Fort Scott TUI’s tumbling mechanism at the same price.

The Subsonic Expansion Problem — And Winchester’s Solution

Standard hollow point bullets rely on hydraulic pressure to force the cavity open. Below approximately 1,100–1,200 fps, that pressure may be insufficient.

A conventional hollow point at 1,060 fps can penetrate without opening at all.

The Winchester Super-X 300 Blackout Power-Point Subsonic addresses this through four engineering choices:

Strategic notching. Pre-cut notches in the hollow point cavity provide mechanical initiation points for petal expansion. Rather than relying solely on hydraulic pressure, the notches initiate at lower impact forces.

Contoured jacket. The jacket geometry is specifically shaped to support maximum expansion petal deployment — holding petals together during initial tissue entry, then releasing consistently as expansion progresses.

Alloyed lead core. A harder lead alloy (rather than pure lead) increases density and rigidity. The alloyed core retains more weight through penetration and prevents the bullet from simply disintegrating at the impact velocities subsonic loads produce.

Copper plating. The copper surface reduces bore fouling and provides a consistent bearing surface.

499 ft-lbs — A Meaningful Energy Claim for Subsonic

At 200 grains and 1,060 fps, the Winchester Super-X 300 Blackout produces 499 ft-lbs — the highest muzzle energy of the subsonic .300 BLK options in this category.

The Fort Scott TUI at 190 grains and 960 fps produces approximately 389 ft-lbs. Heavier bullet, modestly higher velocity, meaningful energy advantage.

Specifications

• Caliber: .300 AAC Blackout (7.62×35mm)
• Bullet: 200 grain, Copper Plated Hollow Point (CPHP) — Power-Point Subsonic
• Muzzle velocity: 1,060 fps (subsonic)
• Muzzle energy: 499 ft-lbs
• Application: Suppressed home defense, subsonic hunting
• Lead free: No — alloyed lead core
• Cartridge case: Brass, reloadable
• Primer: Centerfire
• Quantity: 320 rounds (16 × 20-round boxes)
• Winchester SKU: X300BLKX

Browse the .300 AAC Blackout ammunition category. Specifications are published by SAAMI and by Winchester directly. Safe storage guidance is available from the NSSF.

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SHORT DESCRIPTION (above Add to Cart)

Winchester Super-X .300 AAC Blackout. 200-grain Power-Point Subsonic CPHP, 1,060 fps, 499 ft-lbs. Strategic notching, contoured jacket, and alloyed lead core for reliable expansion and weight retention at subsonic velocity. Brass, reloadable. Winchester SKU X300BLKX. 320 rounds (16 × 20-round boxes). Subsonic suppressor load — not a standard range or hunting round.

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💬 Before You Go — Running Suppressed Subsonic .300 BLK?

Using this for suppressed home defense or hunting? Leave a review with your suppressor, host rifle, and barrel length — and whether you’ve had a chance to document expansion. Subsonic HP performance data from real use is genuinely scarce. And if you came looking for a .300 BLK load we don’t carry, tell us. 🎯

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Please purchase and use ammunition responsibly and in accordance with all federal, state and local laws. Ammunition cannot be shipped to all jurisdictions — verify legal shipment to your address before ordering. Buyers must be of legal age in their jurisdiction. Not for sale to prohibited persons. Suppressors are regulated under the National Firearms Act — verify local laws before purchasing.

Frequently Asked Questions

How does the Winchester Super-X compare to the Fort Scott TUI for subsonic use? Different mechanisms, similar price ($1.56/round for both at 320 rounds). The Winchester uses a conventionally-shaped hollow point with strategic notching and jacket contouring to achieve expansion at 1,060 fps. The Fort Scott TUI uses a solid copper tumbling mechanism at 960 fps. Winchester produces more muzzle energy (499 vs ~389 ft-lbs). Fort Scott uses solid copper (no lead). Choose Winchester for the conventional HP approach with more energy; choose Fort Scott for solid copper tumbling and a non-HP mechanism.

What is “strategic notching”? Pre-cut notches in the walls of the hollow point cavity. Standard HP bullets expand when the cavity fills with fluid and pressure forces the walls outward. Notches provide mechanical initiation points that lower the minimum velocity required to start expansion — enabling the bullet to begin opening at 1,060 fps rather than needing 1,200+ fps.

What is an alloyed lead core? Standard lead cores are soft — at low impact velocity they can deform and lose integrity before the jacket controls expansion. An alloyed (harder) lead core resists disintegration, retains more weight through the penetration channel, and helps control the expansion rate.

What’s the muzzle energy versus the Sierra GameChanger supersonic load in this category? Sierra GameChanger 125gr at 2,115 fps: approximately 1,245 ft-lbs. Winchester Super-X 200gr at 1,060 fps: 499 ft-lbs. The supersonic load delivers far more energy but is not subsonic and not suppressor-optimised for hearing-safe use. Different applications.

Can this cycle without a suppressor? Subsonic .300 BLK can be unreliable in unsuppressed gas-impingement ARs — the suppressor adds back-pressure that ensures reliable cycling. Test function reliability with your specific host rifle before relying on it for defensive use.

Is the brass reloadable? Yes — standard brass, Boxer-primed.

How many rounds is 320? 16 × 20-round boxes.

What’s the per-round cost? $500 / 320 = $1.5625 per round.