The HK45 is the only known gun that they can pick
I don't think any gun meets the specs other than the HK 45
3.3.3. Accessory Rail. The JCP shall have an integral MIL-STD-1913 rail for the attachment of accessories (T). The rail shall be located forward of the trigger guard on the lower portion of the frame (T).
3.4.1. Action: The JCP shall function in double action/single action (DA/SA) or double-action only (DAO) including Striker-Fired Action (SFA) (T). The JCP should have a modular action mechanism that allows reconfiguration at the unit level without modification to the weapon¡¦s major assemblies (O).
3.4.2. Trigger Pull: All DA/SA pistols shall have a consistent trigger pull of eight to ten [8-10] pounds on Double Action, and a consistent trigger pull of four to six [4-6] pounds on Single Action and all DAO pistols shall have a trigger pull of five to eight [5-8] pounds (T). All pistols shall have a trigger pull that is consistent within one [1] pound from average pull (T). When pressure is applied to the JCP trigger and then released, the trigger shall reset to its forward-most position, even if the pistol is not fired (T). The operator shall be capable of pulling the trigger, without shifting the firing grip as will be tested in section 3.6.3.
3.4.4. Ergonomic Enhancements: The JCP shall be operable for a range of operators from the 5th to 95th percentile per section 3.6.3. To aid in this, the JCP should incorporate a modular grip adjustment system to provide enhanced ergonomics (O).
3.4.6.1. DA/SA Pistols. The JCP in the DA/SA configuration shall have an internal safety mechanism that prevents the loaded cartridge from firing if the pistol is dropped or struck and mechanically prevents the firing pin/striker from contacting the cartridge primer unless the trigger is pulled (T). DA/SA pistols shall have a de-cocking lever that lowers the hammer from a cocked position and returns the pistol to DA mode when activated (T). The JCP design shall prevent the firing of a chambered cartridge when the hammer is cocked and the de-cocking lever is activated (T). The operator shall be capable of activating the de-cocking lever with the firing hand (T). The operator should be capable of activating the de-cocking lever without shifting the firing grip (O). If configured with external safety, the weapon shall meet the requirements of 3.4.6.1.1.
3.4.6.1.1. DA/SA Pistols with External Safety. The JCP in DA/SA mode with an external manual safety shall meet all the requirements of 3.4.6.1 with the addition of: The external manual safety shall prevent firing when the manual safety is applied and the trigger is pulled (T). The operator shall be capable of activating the external manual safety with the firing hand (T). The operator should be capable of activating the external manual safety without shifting the firing grip (O).
3.4.6.2. DAO Pistols. The JCP in DAO shall have an internal safety mechanism that prevents the loaded cartridge from firing if the pistol is dropped or struck and mechanically prevents the firing pin/striker from contacting the cartridge primer unless the trigger is pulled (T). If configured with an external safety, the pistol shall meet the requirements of 3.4.6.2.1.
3.4.6.2.1. DAO Pistols with External Safety. The JCP in DAO with an external safety shall meet the requirements of 3.4.6.2 with the addition of: The external safety shall prevent firing when applied and the trigger is pulled (T). When configured with an external safety, the operator shall be capable of activating and deactivating the external safety with the firing hand (T), and should be capable of activating and deactivating the external safety without shifting the firing grip (O).
The SIG is out. The Glock is out. The Smith M&P is out (despite the name), the Walther is out, The Ruger is out. Who else, other than HK has a gun like this?