Hornady Critical Duty 357 Mag FlexLock – Effective Revolver Load

Description

The Hornady Critical Duty 357 Mag FlexLock is the revolver entry in Hornady’s duty line, and it is deliberately light for the calibre. A 135 grain FlexLock at 1275 fps carries about 487 ft-lbs, and the reduced bullet weight is there to keep recoil and muzzle flash under control in the short barrelled revolvers most people actually carry.

• Hornady Critical Duty 357 Mag FlexLock Overview
• 357 Magnum Duty Ammo Ballistics
• Why The 135 Grain FlexLock Bullet Suits A Short Barrel
• Specifications
• Revolvers That Suit This Barrier Blind Revolver Defense Load

Hornady Critical Duty 357 Mag FlexLock Overview

Hornady item 90511 loads a 135 grain FlexLock bullet to a nominal 1275 fps, producing roughly 487 ft-lbs at the muzzle. Twenty five rounds per box.

Hornady publishes the curve from an eight inch test barrel: 1275 fps and 487 ft-lbs at the muzzle, 1150 fps and 396 ft-lbs at fifty yards, and 1058 fps and 336 ft-lbs at a hundred. It is worth being clear that eight inches is a long barrel, and a two or three inch revolver will chronograph well below those figures.

That barrel length matters more in 357 Magnum than in almost any other cartridge. The round was designed around a long barrel and slow powder, and short barrelled revolvers give up several hundred feet per second along with a great deal of unburned powder as muzzle flash.

The FBI protocol is a specific test sequence rather than a general endorsement. Ammunition is fired into calibrated gelatin bare, through heavy clothing, through steel, through wallboard, through plywood and through automotive glass at two angles, with expansion and penetration measured in each. Performing well across all eight is genuinely difficult.

357 Magnum Duty Ammo Ballistics

At 1275 fps a 135 grain bullet produces about 487 ft-lbs, from grains times velocity squared divided by 450437. That is a figure that sits between the 45 ACP and the 10mm loads in the same Critical Duty line.

From a short barrelled revolver expect meaningfully less. A two inch snub will typically lose three hundred feet per second or more against an eight inch test barrel, which takes the energy figure down toward the low three hundreds.

Hornady chose 135 grains rather than the traditional 158 for exactly that reason. A lighter bullet reaches its working velocity in a shorter barrel and leaves less powder burning outside the muzzle, which is why this reads as short barrel 357 defensive ammunition rather than a full house magnum hunting load.

Muzzle flash is the other short barrel problem, and it is worth taking seriously. A bright fireball in a dark room can cost you your sights for several seconds, and Hornady tunes the powder here to limit it.

Why The 135 Grain FlexLock Bullet Suits A Short Barrel

The FlexLock design solves two separate failure modes. A conventional hollow point pushed through heavy clothing can pack its cavity with fabric and never open at all. Hornady fills the cavity with a soft polymer Flex Tip, which cannot pack and is driven rearward on impact to start expansion from the inside out.

The second is the jacket and core separating. A bullet that meets automotive glass or sheet steel and sheds its core loses most of its ability to keep going. Hornady adds a mechanical InterLock band that grips the core and holds the two together, which is where the weight retention comes from.

Barrier blind is the shorthand for that result. The bullet behaves much the same whether it reaches its target directly or through a windshield, a car door or an interior wall, and the FBI protocol exists to measure exactly that spread.

A lighter bullet also expands more reliably at reduced velocity, which is the quiet advantage for anyone carrying a snub nose. A 158 grain bullet leaving a two inch barrel may be moving too slowly to open properly; a 135 grain FlexLock bullet is designed to work in that window.

None of that changes what the 357 Magnum fundamentally is. It remains one of the most effective handgun cartridges available, with a long record behind it, and the bullet design simply makes more of that record available from the barrel lengths people carry.

That is the whole case for a barrier blind revolver defense load built this way: it opens at the velocities a carry revolver actually produces, and it stays together when something gets in the way first.

Specifications

Revolvers That Suit This Barrier Blind Revolver Defense Load

Any revolver chambered in 357 Magnum in sound working order will fire this load. That covers the Smith & Wesson 686, 66, 640 and 340PD, the Ruger GP100, SP101 and LCR, the Colt Python and King Cobra, and the Kimber K6s.

A 357 revolver also fires 38 Special, which makes practice far cheaper. Many owners shoot 38 at the range and keep a 357 Magnum duty ammo load in the cylinder for carry.

In a lightweight scandium or titanium revolver, consider whether you will actually practise with it. A 340PD firing full power 357 is punishing enough that many owners end up carrying 38 Special +P instead, and a load you shoot well beats one you flinch through.

Sight regulation is worth checking. Fixed sight revolvers are usually regulated around a 158 grain bullet, so a 135 grain load may print low at twenty five yards. Confirm it before you rely on it.

For a barrier blind revolver defense load the cylinder capacity is the real constraint rather than the ammunition. Five or six rounds is what you have, so shot placement carries more weight here than in any semi-automatic.

Short Barrel 357 Defensive Ammunition Availability

This Hornady Critical Duty 357 Mag FlexLock is in stock and ships from our Collegeville, Pennsylvania shop. MAG5 Firearms is a family owned FFL dealer, and orders of this short barrel 357 defensive ammunition normally leave within one business day.

The same bullet in a semi-automatic bottleneck is the Hornady Critical Duty 357 Sig FlexLock. For a pistol, see the Hornady Critical Duty 9mm 124gr FlexLock or the heavier Hornady Critical Duty 45 ACP FlexLock. Full ballistics are published by Hornady.