MythBusters · Video summary

Do past myths hold up when retested? | MythBusters | S4 E07 | Full Episode

Mythbusters revisit fan-submitted myths, finding that cartoon physics rarely apply to real-world scenarios, especially with firearms and musical instruments.

MythBusters · January 13, 2026 · 49-min episode · 6-min read

Do past myths hold up when retested? | MythBusters | S4 E07 | Full Episode

Key takeaways

💪The effectiveness of a seal is critical; a trombonist's lips offer a better seal than just the mute, but not enough to launch the slide, and a welded-shut mouthpiece is needed for maximum pressure buildup.03:04
🎯Cartoon physics often fail in reality; a finger in a gun barrel does not cause it to explode like in cartoons, and a trombone slide doesn't become a missile when the mute is filled with explosives.04:34
🚀When evaluating claims or scenarios, question whether they rely on realistic physics or idealized cartoon physics.04:34
📚Fan feedback and suggestions are valuable for refining experiments, leading to more accurate testing by incorporating details like skin layers on ballistics gel or using specific antique firearms.05:45
💡The composition and construction of materials significantly impact outcomes; antique Damascus barrels on shotguns can split and peel when blocked, unlike modern barrels.05:51
🔧For critical applications, research the specific material properties and historical context of components, as these can drastically alter outcomes.05:51

Chapters

0:01🎬 Introduction and Episode Overview
1:52🔍 Revisiting the Trombone Myth
3:05🔥 Attempting to Seal the Trombone Mouthpiece
9:44🎺 Explosive Trombone Test Results
9:44💥 Damascus Barrel Experiment
10:24🔫 Finger in the Barrel Myth and Steel Finger Test
12:00🎥 Shotgun Explosion Test Results
12:40🎶 Musical Mishap: Fireworks in a Trombone
16:12🧨 Fireworks Explosion Results
20:06🔫 Shooting a Bullet Through a Scope
23:09⚙️ Impact of Using Early-Style Scope and Ammo
27:40🛡️ Using Armor-Piercing Ammunition
27:55🪓 Hammerhead Explosion Myth Test
32:49🔨 Hardened Hammer Tests and Explosive Results
35:01🎯 Final Shot: Sniper Shot with Armor-Piercing Ammo
35:34🎯 Sniper Scope Penetration Test Results
36:09🧪 Autopsy and Bullet in the Dummy
36:54✅ Conclusion on the Sniper Scope Myth
37:26⚠️ Antique Hammer and Blacksmith Tests
38:24💣 Testing Exploding Hammer Myth — Summary

The digest

High-Level Overview

This special MythBusters episode revisits several previously tested myths, addressing fan criticisms and new hypotheses to verify if earlier conclusions still stand. The episode focuses on the famous "Mad Trombonist" myth, the "finger in the gun barrel" scenario, the sniper scope bullet-through test, and the "exploding hammer" claim. These re-examinations reflect the show's commitment to rigorous testing, continuous improvement, and audience engagement. The episode offers valuable insights for enthusiasts of physics, ballistics, and myth-busting methodology, emphasizing how evolving evidence and techniques can refine earlier findings.

Keep reading in The Digest

The full 6-minute article, 27 more sections, and every new episode from MythBusters and the creators you follow.

Revisiting the Mad Trombonist Myth: Can Explosives Propel a Trombone Slide? (00:25–16:44)
Fan Criticism and New Angle
New Tests and Methodology
Results
Conclusion
The Finger in the Barrel: Does it Cause a Gun to Explode Like in Cartoons? (04:30–18:03)
Previous Experiment and Fan Feedback
New Setup
Outcomes
Further Testing with Steel Plugs
Verdict
Can You Shoot a Sniper Through His Scope? Sniper Scope Myth Revisit (20:41–37:01)
Initial Findings
Fan Criticism and Additional Considerations
Revised Testing Approach
Results
Conclusion
The Myth of the Exploding Hammer: Can Hammers Shatter on Impact? (27:55–38:43)
Background
Fan Recommendations
Expert Involvement
Testing
Outcomes
Verdict
Key Frameworks and Testing Principles
Practical Implications & Takeaways
Action-Oriented Summary