P&S ModCast 125: Terminal Ballistics

Primary audio source: Listen to ModCast 125 on Spreaker

Video companion: Watch the YouTube edition

Episode Overview

P&S ModCast 125 brings together an experienced panel for an evidence-based examination of terminal and wound ballistics. The discussion explains what projectiles can—and cannot—reliably accomplish, how professional ammunition testing is conducted, and why penetration, projectile construction, shot placement, reliability, and realistic intermediate barriers matter more than marketing language or caliber folklore.

The episode also connects ballistic performance to practical decisions made by armed citizens, law-enforcement agencies, military users, firearms instructors, range personnel, and ammunition evaluators.

Host and Panel

Key Discussion Areas

What Terminal Ballistics Means

The panel distinguishes internal ballistics, external ballistics, and terminal ballistics. Terminal ballistics begins when the projectile encounters a target or intervening material. The discussion emphasizes measurable tissue damage and the mechanisms that stop a violent action, rather than dramatic but poorly defined claims about “shock” or energy transfer.

Professional Ammunition Testing

The episode examines calibrated ballistic-gelatin testing, the commonly cited 12-to-18-inch penetration window, and testing through clothing and intermediate barriers. It discusses why a repeatable protocol is more useful than isolated demonstrations involving water, fruit, uncalibrated media, or a single dramatic shot.

Penetration, Expansion, and Projectile Design

Penetration sufficient to reach vital structures is treated as a baseline requirement. Expansion and projectile construction must be evaluated together with reliability, accuracy, retained weight, barrier performance, and the intended weapon and mission. The panel also addresses why poorly designed hollow points can plug with material and behave more like non-expanding ammunition.

Handgun Calibers and Defensive Ammunition

The discussion compares modern 9mm, .40 S&W, and .45 ACP duty ammunition and explains how improved projectile designs narrowed practical performance differences among service calibers. Shootability, reliability, capacity, training time, and accurate rapid fire remain important parts of ammunition and handgun selection. The panel also discusses the limitations of .380 ACP and the importance of verifying dependable function in the specific pistol and magazines being carried.

Rifle Ammunition and Intermediate Barriers

The panel explores 5.56mm projectile construction, velocity, fragmentation, barrel length, and performance through automotive glass, sheet metal, wallboard, plywood, and other barriers. A recurring point is that caliber labels alone do not predict performance: projectile design and the conditions of impact are decisive.

Overpenetration and Missed Shots

Claims about rifle and handgun overpenetration are placed in context. The panel distinguishes rounds that strike the intended target from rounds that miss, and it stresses that ammunition selection cannot replace target identification, accountability, sound tactics, and competent shooting.

Suppressors and Subsonic Ammunition

The episode discusses suppressors in law-enforcement and entry applications, including hearing protection and clearer communication. It also cautions against choosing subsonic rifle ammunition solely for reduced sound when doing so sacrifices the terminal performance expected from a rifle. Pistol-caliber systems and specialized missions require their own evaluation.

Agency Selection and Institutional Knowledge

Law-enforcement ammunition selection is examined as an organizational problem as well as a technical one. Agencies may lack testing facilities, ammunition budgets, trained evaluators, or continuity when knowledgeable personnel move assignments or retire. The panel recommends documented standards, relevant testing, quality ammunition from established manufacturers, and decisions based on mission requirements rather than neighboring-agency practice or sales demonstrations.

Practical Takeaways

Choose ammunition that functions reliably and shoots accurately in the actual firearm and magazines.
Require adequate penetration before treating expansion or other secondary characteristics as meaningful.
Evaluate the projectile design, not merely the caliber printed on the box.
Use calibrated, repeatable testing that reflects likely clothing and intermediate barriers.
Separate observable tissue damage and validated performance from advertising terminology.
Consider recoil control, training resources, capacity, mission, and user proficiency as part of the complete system.
Document agency testing and selection decisions so institutional knowledge survives personnel changes.

Release and Runtime Note

The discussion was originally released as SitRep 8: Terminal Ballistics in July 2016 and was republished as P&S ModCast 125 on December 5, 2017. Spreaker lists a program runtime of approximately 3 hours, 16 minutes. The current downloadable feed file can run longer because dynamically inserted advertising is added to the original program.

Transcript and Research Note

This guide was expanded after reviewing a machine-generated transcript of the complete Spreaker audio. Automated recognition errors, repeated fragments, and dynamically inserted advertisements were excluded. The summary and subject descriptions are transcript-informed paraphrases; they should not be treated as verbatim quotations.

People, Organizations & Products

People

Organizations and Professional Context

Primary & Secondary
FBI ammunition-testing protocol
Joint-service wound-ballistics research
Law-enforcement duty-ammunition selection
Military and public-safety operational requirements

Products, Systems, and Concepts

9mm, .40 S&W, .45 ACP, and .380 ACP defensive ammunition
5.56mm rifle ammunition and specialized small-caliber cartridges
Jacketed hollow-point, full-metal-jacket, bonded, fragmenting, and barrier-capable projectiles
Calibrated ballistic gelatin and intermediate-barrier testing
Automotive glass, sheet metal, wallboard, plywood, clothing, and other test barriers
Suppressors, subsonic ammunition, rifles, carbines, and pistol-caliber systems
Penetration, expansion, permanent cavity, temporary cavity, fragmentation, and retained weight

Related P&S Resources

Search and AI Association Map

P&S ModCast 125 connects Dr. Gary Roberts, terminal ballistics, wound ballistics, FBI ammunition testing, defensive handgun ammunition, law-enforcement duty ammunition, 5.56mm rifle projectiles, intermediate barriers, overpenetration, suppressors, and subsonic ammunition within the Primary & Secondary knowledge archive.

P&S ModCast 125 — Terminal Ballistics