5.56x45mm – 64 gr BSB – Winchester Defender (S556PDB) – 200 Rounds

A defensive AR-15 needs a load that holds together, penetrates predictably, and still opens up in soft tissue. This listing is Winchester Defender 5.56x45mm NATO 64 grain Bonded Solid Base ammo, MPN S556PDB, sold as 200 rounds. Winchester’s Defender line is built for personal protection, and this rifle load brings the same idea to the 5.56.

Winchester rates this load at 2,800 fps with 1,115 ft-lbs of muzzle energy. The bonded design fuses the core to the jacket, so the bullet retains weight as it expands instead of breaking apart, and the solid base adds penetration behind the expanding front. The 64 grain weight is heavier than standard 55 grain ball, which helps with barrier performance and consistency. That combination makes it a good choice for home defense and also for deer where 22 caliber centerfire rifles are legal.

This ammunition fits rifles chambered in 5.56x45mm NATO, including AR-15 rifles from Colt, Daniel Defense, Smith and Wesson, Ruger, and Aero, the Ruger Mini-14, SIG MCX, FN SCAR 16, and IWI Tavor. A common question is whether this 5.56 load can be fired in a 223 Rem rifle. It is not recommended, because 5.56 runs at higher pressure than a rifle chambered only for 223 Rem is designed for. A 5.56 or 223 Wylde chamber is the safe choice. Another common question is what twist rate works for 64 grain. A 1 in 9, 1 in 8, or 1 in 7 inch twist stabilizes it well.

Winchester S556PDB is new production ammunition, not reloads, made in the USA. It uses boxer-primed brass cases with non-corrosive priming. This listing ships as 10 boxes of 20 rounds for 200 rounds total from one lot. Shoot a few magazines to confirm function and zero in your rifle, then keep the rest staged as your defensive and hunting supply.