How about making a handguard module or something similar, it should be difficult to make, not so that every cap could go to the military and run with it right away, i.e. a second version of the maplestrike, slightly modified, to which you can attach a handle?
You can also make this handguard drop only from the horde beacon with a small chance
For example, you make this modification/knock it out from the horde beacon and with the help of a torch you can attach it to a regular maplestrike and you will get a maplestrike to which you can attach a handle (you can slightly change the model)