Maxim Defense SBA 7.62x39mm ammunition (brand part no. MXM-49003) loads a 117-grain monolithic copper bullet built around TUI, Tumble Upon Impact technology, and it exists because standard rifle bullets lose effectiveness when fired from the short barrels that define the SBR platform. Maxim Defense partnered with Fort Scott Munitions to engineer a bullet that tumbles immediately on contact, producing wound cavities that exceed both expanding and fragmenting projectiles, and that tumbling continues reliably down to 500 fps, well below what a suppressed short-barrel rifle typically generates. The result is 7.62x39mm rifle ammunition that keeps its terminal performance exactly where standard loads start to fall apart.

Key Specifications

• The chambering is 7.62x39mm, the caliber behind the AK platform and a growing number of SBR builds.
• The bullet weighs 117 grains, tuned specifically for the SBA load’s terminal performance goals.
• The bullet is solid copper, a monolithic design rather than a traditional lead-core jacketed bullet.
• Being lead-free, the copper construction avoids the core fragmentation that can rob a traditional jacketed bullet of weight and penetration.
• The bullet is engineered to tumble upon impact (TUI), creating an irregular wound channel immediately on contact.
• That tumbling action stays reliable down to 500 fps, so performance doesn’t fall off as velocity drops from a short barrel or suppressor.
• The load is optimized specifically for SBR-length rifles, where standard ammunition loses velocity and terminal effect.
• Each box holds 20 rounds, enough to run a real function and accuracy check.
• Average cost runs about $1.83 per round, in line with premium purpose-built defensive ammunition.

Frequently Asked Questions

What does TUI mean? Tumble Upon Impact — the bullet is engineered to tumble immediately on contact for a wound channel that exceeds standard expanding or fragmenting projectiles.

Why is this ammunition marketed for SBRs? Maxim Defense developed it with Fort Scott Munitions specifically to maintain terminal performance from the shorter barrels and lower velocities of SBR-length 7.62×39 rifles.

Does the bullet still work at suppressor-reduced velocities? Yes, the TUI design continues to tumble reliably down to 500 fps.

Buy Maxim Defense SBA 7.62x39mm 117gr TUI Ammunition

A short-barreled 7.62×39 gives up velocity that standard ammunition depends on, and SBA is the load Maxim Defense built to close that gap. Run a box through your SBR and see what TUI does at the range you actually shoot. Order from our Lubbock, Texas gun shop and it ships fast to your door.