[Nursik]

So to make it i think i'll need OnPlayerRunCmd and particle (or is it a projectile also?) touching the projectile to remove it, but how do i detect particle touching the projectile?

[Nursik]

Can someone help me detect when the projectile is close to an engie at least?

[Benoist3012]

Actually you want to block the secondary attack of the short circuit, and force the primary attack instead?

Edit:
If you want to do that I made the code for you:

#define SHORT_CIRCUIT 528

public Action OnPlayerRunCmd(int client, int &buttons, int &impulse, float vel[3], float angles[3], int &weapon, int &subtype, int &cmdnum, int &tickcount, int &seed, int mouse[2])
{
    if(client >= 1 && client <= MaxClients && IsClientInGame(client))
    {
        int iActiveWep = GetEntPropEnt(client, Prop_Send, "m_hActiveWeapon");//Get the active weapon of the player.
        if (iActiveWep > MaxClients && GetEntProp(iActiveWep, Prop_Send, "m_iItemDefinitionIndex") == SHORT_CIRCUIT)//Detecting the classname tf_weapon_mechanical_arm would also work.
        {
            if (buttons & IN_ATTACK2)//If the player is pressing the secondary attack button
            {
                buttons &= ~IN_ATTACK2; //Trick the server into thinking the player didn't press the secondary attack button.
                buttons |= IN_ATTACK; //Trick the server into thinking the player pressed the primary attack button.
                //Note: If the secondary attack button is linked to some animations, they will still be played on the client-side, because of client's prediction (It can't be avoided).
            }
        }
    }
}