A pistol disappears into spray, is exposed to salt water in an open boat or returns to the surface after a dive. Minutes later, it is expected to function. The scenario appears self-explanatory; technically, it is anything but. Between contact with water and the first shot lies a chain of material selection, surface treatment, drainage, lubrication, ammunition, carriage and operating procedures.

The ability to fire under water is a different capability from surviving transport through salt water. Corrosion resistance is not the same as drainage. A threaded barrel does not by itself create a suppressed weapon system. Nor does a pistol become a “maritime weapon” merely because it appears in the inventory of a naval unit.

The CYBERSMART Tactical series “Maritime handgun systems since 1990” therefore does not investigate a supposed product category. It examines a chain of mission, environment, technical response, testing, procurement and documented employment.

The critical moment often begins above the waterline

Most conventional self-loading pistols are not underwater weapons. Their cartridges, barrels and locking systems were designed to fire in air. Water pressure in the bore and the hydraulic resistance acting on moving components fundamentally alter the loads involved. Without explicit approval, firing under water is neither a credible operational assumption nor serious evidence of “maritime” suitability.

In many military and law-enforcement scenarios, the actual requirement lies elsewhere: the weapon is transported in or near water and employed after resurfacing, landing or boarding. It must then resist moisture and salt, drain reliably, function after temperature changes and remain operable with gloves or wet equipment.

This distinction is central to the series. The HK P11, as a purpose-built design, belongs in the category of genuine underwater weapons. The HK SFP9M, by contrast, exemplifies a conventional self-loading pistol with enhanced corrosion protection. HK’s publicly accessible manual specifies a special salt-water-resistant coating and testing against NATO salt-spray and long-term salt-water requirements. This is manufacturer evidence of defined environmental resistance—not a blanket authorisation to fire under water. HK SFP9/SFP40 Operator’s Manual, section 4.10 “Maritime”

Five categories instead of one marketing label

CYBERSMART Tactical initially assigns every weapon examined to one or more functional categories:

Category	Testable question	Typical evidence
Genuine underwater weapon	Is firing under water an intended and approved design capability?	Manufacturer manual, military regulation, official test
Weapon for employment after the water phase	Does it remain functional after immersion, surf exposure or maritime transport?	Environmental requirement, drainage and function test
Corrosion-optimised service pistol	Which surfaces and internal components are protected against salt water?	Coating specification, salt-spray or long-duration test
Suppressed special-purpose weapon system	Were pistol, ammunition, suppressor, sights and aiming module assessed together?	System manual, acceptance record, documented configuration
Weapon used by a maritime organisation	Is only the user maritime, or was the technical requirement maritime as well?	Procurement record, official photograph, user manual

A weapon may meet several categories. They nevertheless remain separate because each supports a different claim. SIG Sauer describes the P226 Mk25 as having corrosion-resistant internal coatings and a phosphated, hard-chromed barrel. That is technically relevant. Its well-known association with U.S. Naval Special Warfare does not, however, answer every question concerning a formal maritime requirement or the test methods applied. SIG Sauer, Defense Catalog—P226 Mk25

The handgun is only one component of the system

Once a requirement includes signature reduction, target designation or specialised ammunition, evaluating the pistol alone is insufficient. A complete handgun system may include:

• pistol and magazines
• ammunition and ballistic requirements
• suppressor or other signature-reduction device
• visible and infrared aiming or illumination module
• mechanical or optical sights
• holster and retention lanyard
• cleaning, lubrication and drainage procedures
• spare parts, gauges and documentation.

Every addition changes the overall system. A suppressor affects mass, balance, operating dynamics and point of impact. An aiming module adds capability but can complicate handling and holster selection. A corrosion-resistant finish does not eliminate maintenance because it does not reduce friction. The publicly accessible Mark 23 manual makes precisely this point: although the metal surfaces are treated against salt-water corrosion, they still require lubrication. HK Mark 23 Operator’s Manual, maintenance and lubrication

The series therefore uses the term handgun system deliberately. It prevents a pistol from being praised or criticised in isolation for performance that actually depends on the interaction of several components.

Why the period under review begins in 1990

The end of the Cold War changed the missions, organisation and procurement of many armed forces. Special-operations units were increasingly oriented towards regional crises, evacuations, maritime interventions, counter-terrorism and sustained international operations. Materials, coatings, aiming modules and suppressors evolved at the same time.

The year 1990 is therefore an editorial boundary, not the founding date of this publication. Earlier systems are included where they explain technical or doctrinal prerequisites—for example, slide-lock “Hush Puppy” concepts from the Vietnam War or genuine underwater pistols. The principal focus remains on developments, trials and fielding decisions since 1990.

Developed, tested and procured—yet scarcely employed?

Myths surrounding specialised weapons often begin with imprecise verbs. “Used by the SEALs” may mean that a sample was demonstrated, tested, procured, stored in an armoury, used in training or carried on an operation. None of these stages automatically proves the next.

Every CYBERSMART dossier therefore distinguishes at least between:

1. developed or required,
2. demonstrated,
3. tested,
4. procured,
5. officially fielded,
6. issued or allocated to a unit,
7. used in training,
8. carried on an operation,
9. fired during an operation,
10. still in current use.

This distinction is not linguistic pedantry. It determines whether a specialist article documents procurement history or merely perpetuates a familiar user legend.

Sources receive a visible confidence grade

The series applies a straightforward evidence model:

Grade	Meaning	Examples
A—primary evidence	Original document or responsible institution	Manual, requirement, contract, patent, official photograph
B—reliably corroborated	Several independent high-quality sources	Contemporary specialist literature plus institutional confirmation
C—plausible but limited	Identified first-hand testimony or traceable material indication	Interview with a participant, well-documented physical evidence
D—unconfirmed claim	Dealer text, forum post, anonymous user list or unsupported marketing	Research lead only

A manufacturer manual, for example, is a primary source for what the manufacturer specifies and claims. It is not automatically independent confirmation of every test result summarised within it. An identified witness may credibly describe their own work; their recollection still does not replace the contract record.

The opening system: the HK Mk23 Mod 0 and the OHWS

The Mk23 is an especially suitable starting point because it exposes almost every question addressed by the series. It was not designed as the smallest possible sidearm, but as the pistol component of an Offensive Handgun Weapon System comprising pistol, suppressor and laser aiming module. HK’s publicly accessible manual dates the beginning of the programme to 1991, reports exceptional accuracy and reliability figures, and describes functional testing in salt water, surf, sand, mud and other demanding environments. It also records the delivery of the first military pistols to USSOCOM on 1 May 1996. HK Mark 23 Operator’s Manual

Publicly accessible first-hand accounts simultaneously indicate much narrower employment than the myth of the ubiquitous “SEAL pistol” suggests. This tension makes the system technically and historically important: a weapon can succeed in trials and be officially fielded without becoming the best solution for every user or mission.

The accompanying dossier therefore examines more than the pistol. It separates the development requirement, fielded system components, technical design, testing, documented employment and civilian afterlife. Every illustration is identified as showing either a complete historical OHWS, an individual military pistol, a prototype or a civilian Mark 23.

Read the full dossier: HK Mk23 Mod 0 OHWS

What follows

The first editorial cycle combines system profiles with cross-cutting technical dossiers. Planned subjects include:

• HK Mk23 Mod 0 and the civilian Mark 23/MARK 23
• HK SFP9M
• SIG Sauer P226/Mk25
• HK P11 as a genuine underwater weapon
• HK45CT/Mk24 Mod 0
• Glock 19/Mk27 and the debate surrounding so-called Maritime Spring Cups
• Walther P14/P14K and AREX Delta 4AMP as European research candidates whose possible maritime requirements will be classified only after reliable source comparison
• technical dossiers on corrosion, drainage, lubrication, suppressed operation and ammunition.

Not every system will ultimately qualify as “maritime optimised”. Some are included precisely because they reveal the boundary between a documented requirement, user context and retrospective marketing.

Conclusion: the label is not the capability

The central question of this series is not: Which pistol is the best maritime handgun? Such a ranking would improperly merge fundamentally different missions.

The more useful questions are:

• Which water and operational phase was anticipated?
• Which technical response addressed it?
• What was actually tested?
• What was procured and officially fielded?
• Who used the system—when, how and with which accessories?
• Which claim remains unsupported despite frequent repetition?

The first system article applies these questions to the HK Mk23 Mod 0. It examines a weapon whose unusual size was not an accident, but the visible consequence of an exceptionally demanding system concept.

Core publicly accessible sources

1. Heckler & Koch, Mark 23 Operator’s Manual, revised public edition, January 2024.
2. Heckler & Koch, SFP9/SFP40 Operator’s Manual, section addressing the Maritime variant.
3. SIG Sauer, Defense Catalog 2026, P226 Mk25.
4. Heckler & Koch, Mark 23—SOCOM Born Combat Pistol, current manufacturer presentation.

Editorial note

This publication version uses exclusively publicly accessible sources. Privately held books and non-public scans were not used as evidence. The editorial desk welcomes corrections and additional primary sources where their provenance can be documented.