The Kel-Tec PR57 is the only 5.7×28mm pistol on the market built around carry weight as the primary design goal. At 13.86 oz, it weighs roughly half what every other 5.7 handgun does — the FN Five-seveN sits at 25.2 oz, the Ruger-57 at 24.5 oz. Kel-Tec hit that number by skipping the detachable double-stack magazine entirely and building a 20-round internal magazine that loads from the top through the ejection port using stripper clips. Until the PR57 shipped in 2025, the 5.7×28mm cartridge had no carry-format option in any meaningful sense.

The action is a Kel-Tec original: a rotary barrel lockup that handles the 5.7 cartridge's pressure curve in a slide assembly small enough for a polymer-framed carry pistol. The slide is aluminum with a hard-anodized black finish, which is part of how the weight stayed so low. The trigger is a 4.5 lb DAO hammer-fired pull — long and deliberate by carry-gun standards, but consistent. The slide is optic-ready, the sights are fixed front and rear, and the overall length comes in at 7.16" — about an inch shorter than the Five-seveN.

The trade-offs are real and worth understanding before buying. Reloads are slow compared to a detachable-magazine pistol — stripper clips work, but they are not as fast as dropping a fresh mag. The internal magazine cannot be swapped for a backup load on the move. Owners report the recoil impulse is noticeably sharper than the heavier 5.7 pistols, which is the expected consequence of cutting 11 oz of mass. What the PR57 does that nothing else in the caliber can do: it puts 20 rounds of 5.7×28mm in a pistol that disappears under an untucked shirt at a weight closer to a Glock 43X than to anything else chambered in this cartridge.