26 Military Weapons So Bad They Were Regretted Almost Immediately

Not every military investment pays off. Some weapons enter service with high expectations, only to fall apart under real-world conditions or become too expensive to justify. Others simply fail to deliver on what they promised, turning into costly mistakes.

These failures reveal a different side of military development, where ambition, pressure, and flawed design can lead to serious consequences. In some cases, entire programs were scrapped. In others, the damage was already done. Here’s a look at the weapons militaries regret ever putting into service.

Weapons that fail in the field force militaries to rethink doctrine, procurement, and training. From rifles that jammed in Vietnam to ships retired early for mechanical failures, each mistake reveals how easily overconfidence, politics, or bad assumptions can derail an entire program.

Cutting-edge technology often brings cutting-edge problems. Programs like the VH-71 or the A-12 collapsed under their own ambition, proving that advanced designs can fail just as spectacularly as outdated ones if costs and complexity spiral out of control.

When weapons underperform, it's the troops who pay the price. Early M16 failures, unreliable machine guns, and malfunctioning anti-aircraft systems exposed soldiers to unnecessary danger — reminders that procurement errors quickly become life-and-death issues in combat.

Every canceled project drains billions in development, testing, training, and maintenance. Programs like the LCS and Zumwalt didn't just fail operationally — they reshaped naval budgets for years, limiting investment in more practical alternatives.

Studying past missteps helps explain how modern militaries judge risk, evaluate new technologies, and avoid repeating the same mistakes. Understanding what went wrong gives insight into why today's procurement process is more cautious, more complex, and more closely watched than ever.

• Type: Light anti0tank vehicle
• Country of origin: United States
• Manufacturer: Allis0Chalmers
• Year introduced to service: 1956
• Main problem: Crew forced to reload outside the vehicle

Armed with six recoilless rifles, the Ontos delivered enormous firepower for its size. But crews had to exit the thinly armored vehicle to reload, exposing them to enemy fire. Despite flaws, Marines used it effectively in Vietnam ambushes.

• Type: Interceptor aircraft
• Country of origin: United States
• Manufacturer: Convair
• Year introduced to service: 1956
• Main problem: Aerodynamic issues and weak performance

The F02 initially failed to reach supersonic speed until engineers applied the 'area rule' and redesigned the fuselage. Even after fixes, its performance lagged behind expectations, leading to a short operational lifespan.

• Type: Machine gun
• Country of origin: United States
• Manufacturer: Saco Defense
• Year introduced to service: 1957
• Main problem: Frequent parts breakage

The M60 earned a mixed reputation in Vietnam. While offering strong firepower, its operating rod and sear frequently broke under combat stress. Barrel changes were awkward and slow. Although improved later, early models were widely disliked by troops.

• Type: Fighter aircraft
• Country of origin: United States
• Manufacturer: Lockheed
• Year introduced to service: 1958
• Main problem: Very high accident rate

The F104 achieved extreme speed but poor real0world safety. Its tiny wings, unforgiving flight envelope, and poor all0weather ability caused an alarming crash rate00especially in German service0earning it the nickname 'Widowmaker.'

• Type: Battle rifle
• Country of origin: United States
• Manufacturer: Springfield Armory
• Year introduced to service: 1959
• Main problem: Poor handling in jungle warfare

The M14's heavy recoil and full0auto mode proved uncontrollable, and its size hindered troops in Vietnam's dense jungle. Though accurate, it never worked well as an assault0rifle replacement and was phased out quickly.

• Type: Coaxial machine gun
• Country of origin: United States
• Manufacturer: GM Hydramatic Division
• Year introduced to service: 1962
• Main problem: Severe jamming in armored vehicles

Designed for U.S. tanks, the M73 and M219 repeatedly jammed during combat, proving nearly impossible to maintain. Unreliable feeding and fragile components forced the Army to replace the entire line with the much more effective M240.

• Type: Prototype interceptor
• Country of origin: United States
• Manufacturer: Lockheed
• Year introduced to service: 1963
• Main problem: Excessive cost and maintenance

A derivative of the SR071, the YF12 promised unmatched speed, but astronomical costs and maintenance demands made it impractical. Shifts toward missile0based air defense killed the program before mass production.

• Type: Assault rifle
• Country of origin: United States
• Manufacturer: Colt
• Year introduced to service: 1964
• Main problem: Jamming from powder change and lack of cleaning kits

Early M16A1 rifles jammed frequently in Vietnam after a switch to dirtier powder and the false belief that the rifle was self0cleaning. Troops lacked proper maintenance gear, leading to deadly failures. Later fixes improved reliability, but early damage to troop confidence was lasting.

• Type: Under0barrel grenade launcher
• Country of origin: United States
• Manufacturer: Colt
• Year introduced to service: 1966
• Main problem: Unsafe exposed trigger

The XM148 was America's first under0barrel grenade launcher, but its exposed trigger caused accidental discharges. Fragile components further undermined reliability. The superior M203 replaced it quickly.

• Type: Light tank
• Country of origin: United States
• Manufacturer: General Motors
• Year introduced to service: 1967
• Main problem: Unreliable missile system and flammable hull

The Sheridan's 152mm gun0launcher and aluminum hull sounded advanced but proved disastrous. The missile rarely worked in combat, recoil stressed the frame, and the hull ignited when hit. Despite fielding in Vietnam, it never fulfilled expectations.

• Type: Attack helicopter
• Country of origin: United States
• Manufacturer: Lockheed
• Year introduced to service: 1967
• Main problem: Dangerous instability and fatal crash

The Cheyenne combined helicopter flight with fixed0wing speed in a complex hybrid design. Its instability caused a fatal crash, and rising costs doomed the project. It was ultimately replaced by the more practical AH064 Apache program.

• Type: Strike aircraft
• Country of origin: United States
• Manufacturer: General Dynamics
• Year introduced to service: 1967
• Main problem: Wing0box structural failures

The first F111A models suffered catastrophic structural failures in the wing assembly, causing crashes. Later redesigns improved performance, and later variants became excellent strike aircraft, but the early issues nearly doomed the program.

• Type: Bullpup rifle
• Country of origin: France
• Manufacturer: MAS (Manufacture d'Armes de Saint0tienne)
• Year introduced to service: 1978
• Main problem: Incompatible with NATO ammo

The FAMAS performed well using French0made ammo but malfunctioned when fed standard NATO cartridges. Excessive wear and reliability failures hurt export potential and ultimately led France to adopt foreign rifles instead.

• Type: Infantry fighting vehicle
• Country of origin: United States
• Manufacturer: FMC Corporation
• Year introduced to service: 1981
• Main problem: Conflicting design goals

The Bradley's development tried to combine transport capacity, heavy weaponry, and air mobility0an impossible combination. Early prototypes suffered major compromises. Only later upgrades turned it into a respected fighting vehicle.

• Type: Self0propelled anti0aircraft gun
• Country of origin: United States
• Manufacturer: Ford Aerospace
• Year introduced to service: 1982
• Main problem: Radar unable to track real targets

The Sergeant York's radar routinely locked onto irrelevant objects0including rotating barn fans. Its inability to reliably track aircraft, combined with escalating costs, made it one of the most embarrassing U.S. defense failures.

• Type: Semi0auto pistol
• Country of origin: United States
• Manufacturer: Dornaus & Dixon
• Year introduced to service: 1983
• Main problem: Magazine supply failure

The Bren Ten popularized the 10mm Auto round but collapsed after the company failed to procure working magazines. Early customers received pistols with no magazines at all, dooming the otherwise promising design.

• Type: Bullpup rifle
• Country of origin: United Kingdom
• Manufacturer: Royal Small Arms Factory
• Year introduced to service: 1985
• Main problem: Severe early reliability problems

British troops widely criticized the L85A1 for jamming in sand, mud, and cold weather. Only after an extensive rebuild by Heckler & Koch did the rifle become dependable in A2 and A3 forms.

• Type: Stealth bomber
• Country of origin: United States
• Manufacturer: McDonnell Douglas / General Dynamics
• Year introduced to service: 1988
• Main problem: Weight problems and exploding cost

The A12 was intended as a stealth carrier0capable bomber, but worsening weight issues and skyrocketing costs turned it into one of the most infamous procurement failures. The program was canceled before flying prototypes were finished.

• Type: Tilt0rotor aircraft
• Country of origin: United States
• Manufacturer: Bell / Boeing
• Year introduced to service: 1989
• Main problem: High early crash rate and design complexity

Now widely used, the V2 suffered deadly crashes and engineering challenges early in development. Structural instability, software flaws, and extreme mechanical complexity contributed to one of the most turbulent aviation programs ever.

• Type: Semi0auto pistol
• Country of origin: United States
• Manufacturer: Colt
• Year introduced to service: 1992
• Main problem: Poor accuracy and unreliable action

Colt's attempt at a modern handgun failed disastrously. The All0American 2000 suffered from erratic accuracy and an over0complex rotating0breech design. It sold poorly and was quickly discontinued.

• Type: Recon helicopter
• Country of origin: United States
• Manufacturer: Boeing / Sikorsky
• Year introduced to service: 1996
• Main problem: Costs exploded as drones took over its mission

The Comanche promised stealth scouting but became too expensive as unmanned drones emerged. Billions were spent before the Army canceled the project without fielding a single helicopter.

• Type: Assault rifle prototype
• Country of origin: United States
• Manufacturer: Heckler & Koch
• Year introduced to service: 2002
• Main problem: Program ended due to cost and shifting goals

The XM8 was meant to replace the M16/M4 with a lightweight, modular rifle. Although test performance was strong, rising costs, bureaucracy, and changing Army needs led to cancellation. Critics argued it offered too few advantages to justify enormous expense.

• Type: Presidential helicopter
• Country of origin: United States / UK
• Manufacturer: AgustaWestland / Lockheed Martin
• Year introduced to service: 2003
• Main problem: Extreme cost overruns

The VH71 was meant to replace Marine One with a cutting0edge fleet, but its cost exploded far beyond projections. The project burned billions before cancellation, with no operational helicopters fielded.

• Type: Stealth fighter
• Country of origin: United States
• Manufacturer: Lockheed Martin
• Year introduced to service: 2006
• Main problem: Massive cost overruns and software issues

The F35 eventually matured into a capable fighter, but early development was plagued by software bugs, structural issues, and runaway costs. Delays made it one of the most expensive defense projects ever.

• Type: Naval combat ship
• Country of origin: United States
• Manufacturer: Lockheed Martin / Austal USA
• Year introduced to service: 2008
• Main problem: Mechanical failures and bad mission modules

The LCS fleet promised modular versatility, but engine failures, hull cracks, and ineffective mission packages crippled performance. Several ships were retired early0an extraordinary outcome for such a new platform.

• Type: Stealth destroyer
• Country of origin: United States
• Manufacturer: Bath Iron Works
• Year introduced to service: 2016
• Main problem: Unusable ammunition and spiraling cost

The Zumwalt class centered around an advanced gun system whose ammunition became too expensive to procure. With no usable primary gun and only three ships built, the program became a high0profile example of over0ambitious design.