URSA-SEC HK MP5 .22 LR RRS (Steel)

The URSA-SEC HK MP5 .22 LR RRS (Steel) is a rapid reset system, URSA's name for a forced reset device, built for the Umarex-made HK MP5 .22 LR in its rifle, SD, and K pistol forms with the factory trigger pack. It interacts with the trigger bar as the bolt cycles and forces the trigger forward during the reset phase, so every round still takes its own trigger press. It works with the gun's factory two-position safety, which still blocks the trigger. It does not fit the GSG MP5 .22.

URSA is blunt that this is a tuning project rather than a drop-in. Small differences between rifles change how the unit contacts the trigger bar, so expect to fit, test, adjust, and test again; URSA's own guidance is that owners who keep a spare unit dial in faster and that many start with the carbon-fiber version before moving to steel. URSA also warns that rimfire ammunition is inconsistent enough to make out-of-battery ignition the real risk on a tuned .22, and tells owners to stop and inspect after any split or bulged case. The underlying design is open source; URSA manufactures, tests, and supports its version.

Steel is the version to keep in the gun once fitment is settled. URSA backs it with lifetime support and replaces parts that wear out or break in normal use, but sales are final. URSA does not sell its rapid reset systems into jurisdictions where they are prohibited; verify current federal, state, and local law before purchase.