Hornady Critical Defense 308 Winchester Ammo 155 Grain Hornady FTX Polymer Tip Box of 20

Last reviewed: 2026-04-18 by Jake Terry, FFL07/SOT3, NRA-certified firearms instructor.

Hornady Critical Defense 308 Winchester ammunition loads the 155-grain FTX polymer tip bullet to 2785 feet per second from a 24-inch test barrel, generating 2669 foot-pounds of muzzle energy. The FTX — Flex Tip eXpanding — bullet uses a soft polymer insert in the hollow point cavity to initiate consistent expansion regardless of clothing barriers, including denim, leather, and heavy fabric. Critical Defense was engineered for defensive rifle use where overpenetration and barrier performance must be balanced. The nickel-plated brass case reflects ambient light for faster chamber checks in low-light environments and resists corrosion during extended carry. Low-flash propellant formulation reduces muzzle signature and preserves the shooter’s night-adapted vision in home-defense scenarios. Each Hornady Critical Defense round is loaded with Boxer primers in reloadable brass, allowing shooters to reclaim cases after range sessions.

Built for the Box

The 155-grain FTX bullet carries a G1 ballistic coefficient of 0.313 and a sectional density of 0.233, offering a flatter trajectory than heavier 308 Winchester loads while maintaining energy on target at defensive distances. The polymer tip prevents clogging of the expansion cavity when passing through intermediate barriers — fabric, light wood, drywall — that would pack into a traditional hollow point and inhibit opening. Upon impact, the tip compresses rearward, initiating reliable expansion at velocities from 1600 fps to over 2800 fps. Hornady states the FTX design produces large, deep wound cavities across this velocity range, a critical factor for defensive ammunition where a single well-placed shot must stop a threat. The nickel-plated case provides increased feeding reliability in semi-automatic platforms and aids in quick visual confirmation of chamber status.

The Numbers

This load fits standard 308 Winchester chambers and feeds from AR-10, DPMS/LR-308, and bolt-action rifles chambered in 308 Win or 7.62×51 NATO. The supersonic velocity profile maintains stability and energy past 200 yards, though defensive applications typically occur inside 50 yards. Browse the full Hornady 308 Ammo selection for hunting and match alternatives when defensive criteria are not the primary concern.

Who It’s For

Hornady Critical Defense 308 Winchester suits carbine owners who maintain a semi-automatic rifle for home defense or ranch/farm protection. The 155-grain FTX bullet weight reduces felt recoil compared to 168-grain or 175-grain match loads, aiding faster follow-up shots in high-stress encounters. Shooters in states where magazine capacity restrictions apply benefit from ammunition that delivers rapid incapacitation per round. The low-flash propellant is a functional advantage in low-light or no-light conditions where muzzle blast from standard powders can compromise vision and disrupt red-dot or holographic sight acquisition. Reloaders will recover nickel-plated cases for future use, though the cases should be inspected for neck splits after multiple firings due to the harder plating.