Hornady Critical Duty 9mm 124gr FlexLock – Proven +P Duty Load

Description

The Hornady Critical Duty 9mm 124gr FlexLock is the load Hornady built specifically to pass the FBI protocol, and it is one of the few defensive rounds designed around barriers rather than bare gelatin. At 1175 fps from a four inch barrel it carries about 380 ft-lbs, and the bullet is engineered to arrive intact after going through glass, steel or drywall first.

• Hornady Critical Duty 9mm 124gr FlexLock Overview
• 9mm +P Duty Ammo Ballistics
• Why The 124 Grain FlexLock Bullet Works Through Barriers
• Specifications
• Pistols That Suit This FBI Protocol Barrier Blind Load

Hornady Critical Duty 9mm 124gr FlexLock Overview

Hornady item 90216 loads a 124 grain FlexLock bullet to +P pressure at a nominal 1175 fps, producing roughly 380 ft-lbs at the muzzle. Twenty five rounds per box.

Hornady publishes the full curve: 1175 fps and 380 ft-lbs at the muzzle, 1081 fps and 322 ft-lbs at fifty yards, and 1012 fps and 282 ft-lbs at a hundred. The test barrel is four inches, which is what most carry and duty pistols actually have.

Critical Duty and Critical Defense are different products and the distinction matters. Critical Defense is tuned for bare gelatin and heavy clothing out of short barrels. Critical Duty is loaded hotter, in +P where offered, and built to the FBI tactical handgun ammunition protocol.

The FBI protocol is a specific sequence of tests 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, and penetration and expansion are measured in each. A load that does well in all eight is doing something genuinely difficult.

9mm +P Duty Ammo Ballistics

At 1175 fps a 124 grain bullet produces about 380 ft-lbs, from grains times velocity squared divided by 450437. That is a solid figure for a 9mm and it is delivered without the sharp recoil impulse of a lightweight bullet driven very fast.

Velocity holds up well downrange. Losing only about 163 fps over a hundred yards is good behaviour for a pistol bullet, and it means terminal performance does not fall off a cliff at the distances a defensive encounter might actually reach.

The +P loading is what separates this from the standard 135 grain Critical Duty. It adds velocity without moving to a lighter bullet, so the round keeps the sectional density that drives penetration through a barrier.

Recoil in a service sized pistol is firm rather than harsh. A 124 grain bullet at 1175 fps produces noticeably more impulse than a standard pressure practice load, but 9mm +P duty ammo of this weight stays easy to shoot accurately at speed.

Why The 124 Grain FlexLock Bullet Works Through Barriers

The FlexLock bullet solves two separate problems with one design. The first is clogging. A conventional hollow point that passes through heavy clothing can pack its cavity with fabric and fail to open at all. Hornady fills the cavity with a soft polymer Flex Tip that cannot pack, and which is driven backward on impact to start expansion from the inside.

The second problem is separation. A jacket and a lead core hitting automotive glass or sheet steel at 1175 fps want to come apart, and a bullet that sheds its core loses most of its ability to penetrate. Hornady adds a mechanical InterLock band that grips the core and holds the two together, which is where the weight retention comes from.

That is what barrier blind means in practice. The bullet behaves much the same whether it reaches its target directly or through a windshield, a car door or an interior wall, which is exactly what the FBI protocol sets out to measure.

Against a bare target the difference from a good conventional hollow point is modest. Against a barrier it is substantial, and for a duty grade 9mm defensive ammunition choice that is the case that has to be covered.

Expansion is consistent rather than dramatic. Hornady designs for reliable penetration depth first, which generally means a slightly narrower mushroom than a bullet optimised purely for bare gelatin numbers, and a much better chance of reaching the vitals through an arm, a door or a windshield.

Taken together that is what an FBI protocol barrier blind load has to be: a bullet that opens when it should, holds together when it is punished, and reaches the depth it needs either way.

Specifications

Pistols That Suit This FBI Protocol Barrier Blind Load

This is +P ammunition, so it belongs in a pistol rated for +P. That covers essentially every modern service and carry 9mm: the Glock 17, 19 and 45, the Sig P320 and P365, the Smith & Wesson M&P, the Walther PDP, the CZ P-10 and the many 9mm 1911s and 2011s.

Older or lightweight pistols not rated for +P should use standard pressure ammunition instead. If the manual does not say +P, assume it is not.

The nickel plated cases are worth noting for anyone who carries a gun loaded for long periods. Nickel resists corrosion from handling and holster sweat better than bare brass, and it feeds and extracts a little more smoothly.

Practise with it at least occasionally. A 124 grain FlexLock bullet at +P velocity shoots to a different point of impact than a 115 grain range load, and knowing where it lands from your own pistol is the whole reason to buy a box of it.

Duty Grade 9mm Defensive Ammunition Availability

This Hornady Critical Duty 9mm 124gr FlexLock is in stock and ships from our Collegeville, Pennsylvania shop. MAG5 Firearms is a family owned FFL dealer, and orders of this duty grade 9mm defensive ammunition normally leave within one business day.

The same bullet in larger calibres is the Hornady Critical Duty 45 ACP FlexLock and the Hornady Critical Duty 10mm 175gr FlexLock. For a revolver, see the Hornady Critical Duty 357 Mag FlexLock. Full ballistics are published by Hornady.