IronKells Armory | GunBusters

Walls Will Stop Rounds

Interior walls hide people. That does not mean they protect them. Drywall, insulation, hollow-core doors, thin furniture and ordinary residential materials are not designed as ballistic protection, and common handgun, rifle and shotgun projectiles can remain dangerous after passing through them.

Verdict

BUSTED.

Typical residential interior walls should be treated as concealment, not dependable ballistic cover. Drywall can slow, deform, destabilize or fragment a projectile, but common ammunition can penetrate one wall — and sometimes several — while retaining enough energy to remain dangerous.

The Claim

“If the bullet hits a wall, the drywall will stop it.”

Or:

“Hollow points stop in walls.”

Or:

“Birdshot won't go through an interior wall.”

Or:

“A couch, refrigerator or bedroom door gives you cover.”

All of those ideas come from the same assumption:

if something looks solid, it must stop bullets.

Residential construction does not work that way.

Hollywood

Movies have trained people to watch characters hide behind couches, doors, kitchen cabinets and drywall while bullets somehow stop on the other side.

That's convenient for storytelling.

It is terrible ballistic education.

Walls Feel Solid

A finished wall looks substantial.

Paint.

Texture.

Studs.

Insulation.

Drywall on both sides.

But a normal interior wall is mostly empty space.

Hollow-Point Marketing Gets Misunderstood

People hear that JHP ammunition is designed to expand and reduce unnecessary penetration.

Then they assume drywall will make that bullet open immediately and stop.

Sometimes a projectile deforms.

Sometimes it doesn't.

Wallboard is not the same medium as calibrated gelatin.

It Is Comforting

Nobody likes thinking about what a missed projectile may do several rooms away.

“Don't worry, the wall will catch it” feels a hell of a lot better.

Unfortunately, comfort isn't a ballistic property.

Concealment Is Not Cover

This is the first distinction to understand.

Concealment hides you from view.

Cover provides meaningful ballistic protection.

Typical drywall may provide excellent concealment.

It is not something we would automatically trust as cover.

The same caution applies to many ordinary household items.

If a material has not been designed, rated or tested as ballistic protection, don't casually assume it is.

What's Actually Inside a Normal Interior Wall?

Construction varies, but a common framed interior partition may include:

• ½-inch gypsum wallboard on one side
• Wood or metal studs
• A hollow wall cavity
• Sometimes fiberglass or other insulation
• ½-inch wallboard on the opposite side

The wall may be several inches thick from painted surface to painted surface.

But most of those inches are not solid material.

The gypsum itself is relatively brittle.

Fiberglass insulation is not ballistic armor.

And a projectile traveling between studs may encounter surprisingly little solid resistance.

Wall thickness and ballistic resistance are not the same thing.

This is probably the cleanest evidence against the myth.

The standardized handgun-ammunition test used by the FBI includes a wallboard event.

That barrier uses:

• Two pieces of ½-inch standard gypsum board
• Separated by approximately 3.5 inches
• With calibrated ballistic gelatin positioned behind the barrier

Why?

Because the wallboard is not expected to stop the bullet.

The test is designed to determine what the projectile does after it goes through the wall.

That alone should change how people think about ordinary drywall.

Professional ammunition testing treats a typical interior wall as an intermediate barrier, not a backstop.

Modern Handgun Ammunition Can Still Perform After Wallboard

Current manufacturer FBI-protocol data makes this extremely obvious.

Read what those numbers actually mean.

The projectile penetrated the wall.

Then entered a ballistic test medium.

Then continued penetrating a substantial distance.

That is not a projectile we would describe as harmless on the other side of the wall.

There is no honest universal number.

Wall construction varies.

Ammunition varies.

Impact angle varies.

Studs, plumbing, furniture and other materials can change the path.

But controlled demonstrations show why assuming:

“one or two walls will catch it”

is a bad bet.

In one 2021 test using 24 half-inch sheetrock panels spaced to represent successive interior walls:

• Every cartridge tested penetrated multiple simulated walls.
• Tested 9mm and .45 ACP loads penetrated at least six simulated walls.
• The tested 10mm load exceeded ten simulated walls.
• The tested 20-gauge birdshot penetrated three simulated walls.
• The tested 5.56 load penetrated 19 panels — roughly nine simulated walls in that rig.

Those are not universal cartridge specifications.

They're results from one controlled test.

But they're more than enough to kill the belief that drywall is dependable ballistic protection.

“But I Use Hollow Points”

Good defensive JHPs are designed to expand in appropriate target media.

That does not make drywall a bullet trap.

Wallboard can:

• Damage a hollow-point cavity
• Fill the cavity with material
• Change expansion behavior
• Cause yaw
• Strip or deform portions of the projectile

Older JHP designs were particularly vulnerable to cavity clogging.

Some modern duty bullets are specifically engineered to resist that problem and continue expanding after wallboard.

That's actually worse for the myth.

It means manufacturers intentionally test whether a projectile can:

penetrate an interior-wall barrier and still function afterward.

JHP reduces some penetration concerns when it expands as intended. It does not make the material between rooms bulletproof.

FMJ and Walls

Conventional handgun FMJ generally maintains a relatively small frontal diameter.

It is not designed to expand and create extra drag after impact.

That means FMJ often penetrates lightweight building materials very efficiently.

But don't oversimplify this into:

FMJ goes through walls; JHP doesn't.

Both can go through walls.

Projectile construction changes what happens afterward.

People often assume a rifle projectile must penetrate more building material simply because it is traveling faster.

Sometimes it does.

But rifle projectile construction can dramatically change what happens after impact.

A projectile may:

• Stay intact
• Yaw
• Flatten
• Fragment
• Break into multiple pieces

That means two loads with the same caliber marking can behave very differently through lightweight barriers.

The safe conclusion is not:

“Rifles always penetrate more.”

And it is definitely not:

“.223 always stops in drywall.”

Bullet construction matters too much for either slogan to be reliable.

The “5.56 Stops Faster Than Handgun Rounds” Claim Needs Context

Certain lightweight rifle projectiles can fragment after striking barriers and may produce less penetration than some heavy handgun projectiles under particular test conditions.

That is real.

But it is not a caliber-wide guarantee.

The 2021 multi-wall test referenced earlier had its tested 5.56 ammunition penetrate roughly nine simulated walls.

Other projectile designs can behave very differently.

The useful lesson is: never assume the caliber name alone tells you what a projectile will do after wallboard.

Shotguns get surrounded by their own version of this myth.

“It's just shot. The wall will catch it.”

Not necessarily.

Different shot sizes behave very differently.

But even relatively small shot can penetrate more lightweight construction than people expect at close distance.

In the 2021 test mentioned above, the tested 20-gauge birdshot load penetrated the equivalent of three drywall walls.

Larger pellets retain more mass and penetration potential.

“Shotgun” is not a penetration specification.

Even .22 LR Deserves Respect Around Walls

Small caliber does not mean harmless after drywall.

Tests have repeatedly shown .22 LR penetrating multiple sheets of wallboard.

The exact number depends heavily on ammunition, firearm, wall construction and test setup.

But the safety takeaway is easy:

don't count on an ordinary interior wall to make a missed .22 safe.

Small doesn't mean stopped.

What About Doors?

A lot of interior residential doors are hollow-core.

They may contain little more than:

• Thin outer skins
• Light internal framing
• Cardboard or lightweight core material

That is not dependable ballistic protection.

Even solid wood doors vary enormously in species, thickness, construction and hardware.

The FBI-style ammunition protocol includes a separate plywood barrier specifically because wood changes projectile behavior but does not automatically stop it.

“Door” is a construction description, not a ballistic rating.

Furniture Is Unpredictable

A couch may contain:

• Foam
• Fabric
• Thin wood
• Metal springs
• Empty space

A bookshelf might contain thin particleboard or six inches of tightly packed books.

A dresser may be cheap fiberboard or heavy hardwood.

Those are completely different barriers.

Testing has shown dense books can stop some projectiles under certain conditions.

That does not turn every bookshelf into certified ballistic cover.

Random household furniture is too inconsistent to bet lives on.

Appliances Aren't Automatically Cover Either

A refrigerator looks like a giant steel box.

Most of the exterior metal is relatively thin sheet material.

Inside you may have:

• Plastic
• Insulation
• Empty cavities
• Compressor components
• Shelves
• Food and liquid

Depending on the exact impact path, an appliance could slow or stop a projectile.

Another path through the same appliance may not.

Big and metal-looking does not mean ballistically dependable.

What If the Bullet Hits a Stud?

A wood stud is obviously a more substantial barrier than empty wall cavity and two sheets of gypsum.

It may:

• Slow the projectile
• Deform it
• Deflect it
• Fragment it
• Stop it under some conditions

But there are two problems with treating that as protection.

First, studs occupy only part of the wall.

Second, a single piece of residential lumber still isn't standardized ballistic armor.

A stud can change the outcome. You still shouldn't assume it guarantees one.

An exterior wall might include:

• Drywall
• Studs
• Insulation
• Structural sheathing
• House wrap
• Wood siding
• Vinyl siding
• Stucco
• Brick veneer
• Concrete block
• Poured concrete

Those construction systems have wildly different ballistic resistance.

Masonry and concrete can be far more resistant than ordinary wallboard.

A wood-frame exterior wall with lightweight siding is another story.

Never generalize “wall” without knowing what the wall is actually made of.

Brick and Concrete Are More Substantial — Not Magic

Dense masonry is much more credible ballistic protection than sheetrock.

But even here:

• Thickness matters
• Material strength matters
• Hollow versus filled block matters
• Impact angle matters
• Repeated impacts matter
• Projectile type matters

If a structure needs actual ballistic protection, the correct approach is rated ballistic material and an engineered system.

Not guessing from how heavy the wall feels when you knock on it.

A Wall Can Change the Bullet Without Making It Safe

This is important.

Penetrating a barrier can make a projectile:

• Lose velocity
• Deform
• Yaw
• Fragment
• Change direction
• Lose jacket material
• Fail to expand later

People sometimes see a mangled recovered bullet and conclude:

“The wall stopped most of it.”

Maybe the wall reduced performance substantially.

But a projectile does not need to retain original muzzle velocity or perfect shape to remain dangerous.

Barrier degradation and safety are not the same thing.

Drywall Can Make Some JHPs Penetrate More, Not Less

This surprises people.

A JHP normally increases drag by expanding.

If wallboard debris plugs that cavity and prevents normal expansion, the projectile may stay closer to its original diameter.

Smaller frontal area can mean:

deeper penetration afterward.

That's one reason modern duty bullet designs spend so much engineering effort on barrier performance and clog resistance.

The barrier may slow the projectile while simultaneously changing how it behaves in whatever it hits next.

People constantly mix these together.

Problem #1: Projectile passes through an intended target and continues.

Problem #2: Projectile misses entirely and enters the structure.

Both matter.

But they are not the same ballistic event.

JHP expansion can reduce the first risk by increasing drag after entering the target.

That does not guarantee anything about a projectile that misses and enters bare wallboard without ever encountering material that produces normal expansion.

Don't let one meaning of “over-penetration” hide the other.

There Is No Magic “Wall-Safe” Defensive Cartridge

This is probably the most important correction to the old article.

Any projectile capable of meaningful penetration also has the potential to penetrate common lightweight building materials.

Different ammunition can reduce or increase that risk.

None turns an ordinary interior wall into a safe backstop.

If an ammo advertisement or internet comment makes it sound like missed projectiles become harmless when they reach sheetrock, treat that claim with serious skepticism.

Real Houses Are Messier Than Test Rigs

Controlled testing is valuable because it isolates variables.

Real buildings add:

• Studs
• Pipes
• Electrical boxes
• Cabinets
• Furniture
• Doors
• Windows
• Appliances
• Different wall angles
• Different construction materials
• Different distances between walls

Any of those can change projectile behavior.

That's why a test showing six simulated walls does not mean:

“this cartridge always penetrates six walls.”

And a round stopping inside one real wall doesn't prove:

“this cartridge is wall-safe.”

Ballistics live in probabilities and conditions, not internet commandments.

The original Forge File proposed a large IronKells wall-penetration test.

I still like that idea.

But if we eventually publish our own data, it needs to be treated like real testing instead of another YouTube stunt.

At minimum, we'd document:

• Actual wall materials and thickness
• Stud spacing and wall construction
• Exact ammunition tested
• Firearm and barrel length
• Projectile condition after the barrier
• Repeatability across multiple samples
• Whether results came through wall cavity or structural members
• Any downstream velocity or standardized test-medium data available

Then the results would be published as:

“This is what happened in our setup.”

Not:

“This is what every bullet will always do in every house.”

That's the difference between testing and folklore.

Want a Wall That Actually Provides Ballistic Protection?

Then build or buy something intended for that job.

Purpose-built ballistic systems can use:

• Rated ballistic fiberglass
• Ballistic steel systems
• Specialized composite panels
• Rated transparent armor
• Engineered masonry or concrete construction

Those systems are tested against specific ballistic standards.

That's very different from stuffing random materials inside a wall and declaring it bulletproof.

If ballistic protection genuinely matters to a building design, use rated materials and competent installation.

What We're Updating From the Original Forge File

The old article had the right conclusion and a lot of good research.

We're keeping:

• The concealment-versus-cover distinction
• Multiple-wall test examples
• Handgun wall penetration
• Rifle projectile-construction differences
• Shotgun penetration
• JHP clogging
• Exterior-wall differences
• The future IronKells testing concept

But we're cleaning up several things:

• No more universal “X caliber equals Y walls” rules.
• No assumption that all rifle ammunition behaves alike.
• No implication that birdshot is automatically wall-safe.
• No claim that books or furniture should be treated as engineered ballistic protection.
• No recommendation to choose extremely shallow-penetrating ammunition solely to reduce wall penetration.
• No detailed DIY ballistic-test firing procedure.
• More emphasis on the actual FBI wallboard protocol and modern manufacturer barrier data.

The myth stays busted. The numbers get put back into their proper context.

The Practical Safety Takeaway

Assume ordinary interior walls can be penetrated.
Do not treat sheetrock as a safe backstop.

Know what is beyond whatever you're handling or firing toward.
A wall can hide a person without protecting them.

Don't rely on ammunition marketing to make building materials safe.
Projectile design can change barrier behavior, but no common cartridge turns drywall into armor.

Don't assume household objects provide ballistic protection.
Appearance and weight do not equal a tested rating.

Understand your building materials.
Drywall, plywood, brick, block and concrete are completely different barriers.

If ballistic protection is actually needed, use rated systems.
Purpose-built protection beats improvisation.

Remember what a missed projectile becomes.
It becomes somebody else's ballistic problem until something capable of stopping it finally does.

Quick FAQ

Will one normal interior wall make a handgun round safe?

No assumption like that is justified. The FBI protocol specifically tests handgun projectiles after they penetrate a representative wallboard barrier, and modern duty ammunition can still show substantial gelatin penetration afterward.

How many walls will 9mm penetrate?

There is no universal answer. Controlled tests have shown 9mm penetrating several simulated interior walls, but actual results depend on the exact projectile, wall construction, angle and what else the bullet encounters.

Does hollow-point ammunition stop in drywall?

Not reliably. Some JHPs clog or deform, while modern barrier-capable designs may penetrate wallboard and still expand afterward.

Will birdshot penetrate drywall?

Yes, it can. Penetration depends heavily on pellet size, load, range and wall construction, but controlled testing has shown even birdshot penetrating multiple drywall assemblies.

Does brick or concrete stop bullets?

Dense masonry generally provides much greater resistance than drywall, but thickness, construction, projectile type and repeated impacts matter. If true ballistic protection is required, use a rated system.

Can a projectile still be dangerous after several walls?

Yes. Loss of velocity, deformation or yaw does not automatically mean the projectile has lost the ability to cause serious injury.

Related Forge Files

GunBusters: JHPs Are Better Than FMJs
Expansion, penetration, cavity clogging and why JHP does not make missed rounds harmless around building materials.

Handgun Energy Dump Drops Attackers
Why raw energy numbers don't tell you whether a projectile remains dangerous after a barrier.

+P Ammo Will Blow Up Your Gun
Pressure, velocity, projectile performance and why more energy doesn't create simple ballistic rules.

GunBusters: Do Bullets Tumble?
Yaw, keyholing and why a projectile can change orientation after striking intermediate material.

GunBusters: Ammo Explodes in a Fire
Another case where Hollywood physics and actual ammunition behavior are two very different things.

Bottom Line

Drywall is not ballistic armor.

Neither is insulation.

Neither is a hollow-core door.

And most random furniture isn't something we'd trust as rated cover.

Common handgun ammunition can penetrate ordinary interior walls.

Shotgun loads can penetrate ordinary interior walls.

Rifle ammunition can penetrate ordinary interior walls.

Different projectiles may:

• Slow
• Yaw
• Deform
• Fragment
• Continue largely intact

But none of those outcomes should make you assume the projectile is harmless on the other side.

The FBI doesn't test handgun ammunition to see whether wallboard stops it.

They put calibrated gelatin behind the wallboard to see what the bullet does next.

That tells you damn near everything you need to know about the myth.

Walls hide things.

They do not automatically protect them.

Treat lightweight construction accordingly, know what's beyond it, and if you actually need ballistic protection, use materials built and rated for that job.

Sources & Receipts

IRONKELLS ARMORY | GUNBUSTERS

Myth Busted.

Drywall hides what's behind it. It doesn't promise to protect what's behind it.