Terminal Ballistics Blog — BallisticEngine

Game Ballistics vs Real Physics

Escape from Tarkov, Arma 3, and PUBG all model bullet penetration differently — and mostly on purpose. Where the games diverge from real terminal physics, and why.

August 2026 11 min read Game Physics Tarkov Penetration

How Far Do Bullets Travel Underwater?

Water is 800× denser than air. The drag equation, exponential velocity decay, and why rifle rounds stop faster underwater than pistol rounds.

August 2026 9 min read Underwater Drag Equation Physics

Sectional Density Explained: Why It's Not the Whole Story

Sectional density predicts penetration — until it doesn't. Why SD ignores velocity, nose shape, and expansion, and what really drives how deep a bullet goes.

August 2026 9 min read Sectional Density Penetration Physics

Kevlar vs Dyneema: Which Stops More at the Same Weight?

At equal weight vs 9mm, Dyneema UD laminate beats Kevlar by 34% — yet woven Dyneema is 4x worse than both. Patent-verified V50 data: form beats fiber.

August 2026 10 min read Kevlar Dyneema Body Armor

Does Wet Sand Stop Bullets Better Than Dry?

Wetting sandbags makes them worse. A 7.62 ball round reaches 98 mm in dry sand and 263 mm in wet — and the myth has a traceable origin in a manual section about radiation shielding.

July 2026 9 min read Sand Methodology Concrete

What Actually Stops a Bullet — And Why Most Published Numbers Are Wrong

We opened twelve primary sources behind commonly-cited penetration figures — US Army field manuals, Naval Ordnance Laboratory reports, peer-reviewed ballistics papers. Of 22 numbers checked, 17 measured something other than what they were cited for. With the quotes.

July 2026 12 min read Sources Methodology Concrete

What Stops a Bullet? Brick vs Concrete vs Cinder Block

We ran 9mm and .223 through brick, concrete, and cinder block with physics-based penetration modeling. The most solid-looking material fails first — reinforced concrete wins, cinder block doesn't.

July 2026 9 min read Brick Concrete Cinder Block

Will 9mm Penetrate a Brick Wall?

We ran 47 different 9mm loads through our Poncelet penetration model against standard red brick. The answer surprised us — it depends heavily on bullet construction, not just velocity.

June 2026 8 min read 9mm Brick Penetration

Best Home Defense Caliber: 9mm vs .45 vs .380

We compared 9mm, .45 ACP, and .380 ACP with physics-based penetration modeling — energy, penetration depth, and over-penetration risk for each.

June 2026 10 min read 9mm .45 ACP Home Defense

Why Your Home Defense JHP Fails After Drywall

Hollow points clog with gypsum passing through drywall, lose the ability to expand, and over-penetrate like FMJ. We model the FBI Protocol barrier and show why.

June 2026 9 min read JHP Drywall Home Defense

Buckshot vs Birdshot for Home Defense

Birdshot looks devastating up close but fails to reach vital depth; buckshot penetrates but risks over-penetration. The shotshell physics against the FBI 12-inch standard.

June 2026 8 min read Buckshot Shotgun Home Defense