By Benjamin Kurata
During a recent NLEFIA Shoot House Instructor Certification Course, instructors discussed frangible ammunition and its compatibility with suppressors. Students using suppressed rifles reported that some suppressor manufacturers explicitly warn against “conventional” (non-jacketed) frangible ammunition. The cited risk: projectile breakup inside the barrel, which could damage the suppressor and void the warranty.
Warranty concerns appear to stem from a reported (though unverified) incident involving three 30-round magazines of unjacketed frangible ammunition fired full-auto through a suppressed M4 until the system overheated, allegedly causing baffle strikes. (Note: Sustained full-auto fire of this volume is rarely — if ever — necessary or realistic in law enforcement training or operations.)
Several manufacturers now offer frangible projectiles with copper jacketing to help prevent core material from breaking apart in the barrel, reducing the risk of baffle strikes and suppressor damage. This jacketed design appears to be a sensible advancement. However, it raises important considerations that all firearms instructors — especially those in law enforcement — should understand.
Is “jacketed frangible” ammunition real?
Yes. In December 2016, the U.S. Department of Defense (DoD) solicited bids for the Cartridge, 5.56mm, Frangible, Mk311, Mod 3, AA40. Ammunition manufacturers submitted proprietary designs in an effort to secure the contract.
Why did the DoD pursue jacketed frangible ammunition?
A long-standing ammunition manufacturer involved in the DoD solicitation confirmed anonymously that the full-auto incident cited above did occur; however, it involved a polymer-based frangible projectile. Polymer projectiles are highly heat-sensitive. In this case, sustained full-auto fire through a suppressed military M4 generated enough heat to deform the projectile, resulting in suppressor baffle strikes.
Rather than differentiating between frangible projectile compositions, the DoD responded by soliciting jacketed frangible projectiles. NLEFIA could not verify any credible reports of copper-based frangible projectiles coming apart inside the rifle system and damaging a suppressor.
Recommended applications for jacketed frangible ammunition
- Paper or cardboard targets: Accuracy should not be expected to match XM193 55-grain FMJ. The original DoD accuracy requirement for the Frangible, Mk311, Mod 3 was 4.5" average / 6" maximum at 100 yards. This was later relaxed to an 8" maximum due to inconsistent performance.
- Rifle-rated steel shoot houses with intact plywood skins: Avoid repeated target placement in the same locations. Replace damaged plywood and distribute targets to prevent structural degradation.
- Portable bullet traps inside shoot houses: Ensure rifle-rated steel backers and well-maintained plywood faces. Systems incorporating Linatex rubber between plywood and steel significantly reduce internal wear and virtually eliminate back-splatter. Portable stands also disrupt wall-scanning habits and improve threat discrimination.
- Bare, rifle-rated steel targets on a square flat range (SFR): Observe standard FMJ stand-off distances and replace or rotate strike plates at the first signs of pitting or chipping.
(A free PDF of the NLEFIA Steel Target Guide, based on decades of empirical use, is available at nlefia.org.)
Market considerations
Jacketed frangible ammunition is increasingly available on the open market due to DoD contract overruns. At least two major manufacturers — Lake City Army Ammunition Plant (operated by Winchester) and UDC — are selling excess production, alongside numerous smaller manufacturers.
Identifying true jacketed frangible ammunition
Legitimate DoD-contract ammunition will be identified as:
- Mil-Spec Cartridge, 5.56mm, Frangible, Mk311, Mod 3, AA40, and/or
- Compliant with MIL-STD-636 or MIL-STD-1916
Manufacturers that did not secure DoD contracts may still market jacketed frangible ammunition, but their products will not carry these designations.
DoD contracts allow manufacturers to sell overruns on civilian and law enforcement markets, which is often where profitability is realized.
Availability is expected to increase significantly. At the time of this article, the DoD submitted a contract to sole-source this ammunition at multiple millions of cartridges per year for an initial period of eight years.
Important cautions
- Marketing claims do not equate to performance standards.
- Firing ammunition that does not meet SAAMI or NATO specifications can void firearm warranties.
- Duty ammunition should meet FBI testing standards. To date, manufacturers marketing jacketed frangible ammunition for “duty use” have provided no published FBI test data.
Bottom line
Jacketed frangible ammunition should be treated strictly as training ammunition and used under the same safety protocols applied to steel shoot houses and steel targets. Functionally, it should be regarded as comparable to XM193 55-grain FMJ, with reduced accuracy expectations.
Who manufactures “traditional” non-jacketed, copper-based frangible ammo?
There has been significant turnover and acquisition among U.S.-based ammunition companies. At the time of this article, NLEFIA staff were able to verify several sources of traditional non-jacketed frangible ammunition:
- Federal BallistiClean RHT: Available in common law enforcement pistol and rifle cartridges, as well as 12-gauge slug and buckshot.
- CCI Lawman RHT: Available in popular law enforcement rifle and pistol cartridges.
- SinterFire: Offers frangible ammunition with both conventional and lead-free primers. The company also produces frangible projectiles for OEM partners and sells projectiles to hobbyist reloaders.
NLEFIA instructors have fired many rounds from the manufacturers listed above — including through SBRs with suppressors — without experiencing baffle strikes, even when weapon systems were hot to the touch. As always, conduct your own testing and consult manufacturers to ensure any ammunition performs to your expectations.
About the author
Benjamin Kurata is NLEFIA Charter Member #002 and brings more than 30 years of experience as a use-of-force trainer for law enforcement, military and private-sector professionals. He also has over a decade of operational experience spanning street law enforcement, corporate security, executive protection and personal protection.
Mr. Kurata was the first instructor to teach reduced-light live-fire training at the annual conference of the International Law Enforcement Educators and Trainers Association (ILEETA). He is Founding Member #62 of the now 4,000-plus-member international organization and has served as a guest instructor at multiple ILEETA annual conferences.
Over the course of his career, Mr. Kurata has earned 28 instructor certifications from organizations including the SureFire Institute, SIGARMS Academy, ITT Night Vision, Action Target, International Training Inc., Armiger Police Training Institute, Simunitions, UTM and Team One.
During the same period, he also earned 34 operator-level certifications, including armorer certifications for the Remington 870 Police Shotgun, AR-15/M16 rifle, classic SIG pistol line and the Robinson XCR rifle, for which he served as the primary instructor. He also taught the first 1911 Armorer course at the SIGARMS Academy. He is a graduate of the Force Science Institute and a six-time graduate of Thunder Ranch – Texas.
Mr. Kurata co-founded the Law Enforcement Training Division at International Training Incorporated in Texas and the Action Target Academy, and previously served as an instructor at the SIGARMS Academy. He currently serves as an adjunct faculty member in the Criminal Justice Department at the University of the Incarnate Word in San Antonio.
He holds a Master of Science in Criminal Justice from Michigan State University and a Master of Science in Management with high honors from Maryville University.
