Well, anyway, even without X-304 I've made myself some railguns, using Vindicator rapid-fire cannon model and image..
as I've been asked earlier by mail to upload etc my work:
into Modules.xml
<TurretModule name="RAIL">
<short_name>#M_Name_RAIL</short_name>
<hint>#M_Hint_RAIL</hint>
<short_desc>#M_SDesc_RAIL</short_desc>
<long_desc>#M_LDesc_RAIL</long_desc>
<mesh_name>Med_Turret_M205_T</mesh_name>
<flat_image>Med_Turret_M205</flat_image>
<hit_points>20</hit_points>
<mass>100</mass>
<disable_trade/>
<cost>7000</cost>
<technology/>
<attach_type>ONLY_BIGSHIP</attach_type>
<recharge_time>8</recharge_time>
<viewing_angle>10</viewing_angle>
<dispersion>1</dispersion>
<min_distance>10</min_distance>
<max_distance>75</max_distance>
<rate_of_fire>2</rate_of_fire>
<burst_count>18</burst_count>
<azimuth_rotation_speed>60</azimuth_rotation_speed>
<rise_angle_rotation_speed>30</rise_angle_rotation_speed>
<BulletParams>
<damage>25</damage>
<bullet_length>3</bullet_length>
<speed>50</speed>
<damage_type>IMPACT</damage_type>
<graph_type>PLASMA</graph_type>
<sfx_index>4</sfx_index>
</BulletParams>
</TurretModule>
into m_bs_modules.loc
#M_Name_RAIL = R-18
#M_Hint_RAIL = Experimental railgun
#M_SDesc_RAIL = A turret with a rapid-fire experimental railgun.
#M_LDesc_RAIL = This experimental weapon was created by best scientists of MSF to combine raw power of plasma cannons with astounding effectivity of rapid-fire kinetic cannons. This early prototype is still too unaccurate and hard to cool, so the time between bursts is quite long. But with the right person behind the controls, not many spaceships survive even first burst.
into InitTeamScript.script
under the line
MothershipFlight:AddShip(mothership);
mothership:AddModuleToInventory("RAIL",
X);
X = number of turrets you will use on mothership. I use Liger - 8.
It could also be added to market, but there is very high chance it will screw something important and you'll end up using backups. Believe me, I was failing a lot last time when I was adding TurretGKs to markets. And since then my HDD was destroyed. Too bad I haven't uploaded it back then.
I suggest lowering bullet damage if you haven't ovehauled other modules and HPs of fighters, or you end up too powerful.
I have found few very nice X-304 models, but they can't be downloaded for free. Honestly, if I was their creator, I wouldn't give away those masterpieces for free too..
Also, I've noticed that on the original X-304, there are too many railguns (I think about 36 on the roof and 16 on the belly - which is too much for both GUI and game difficulty - or in this case - no difficulty at all - but with recharge time of 60 instead of 8 and damage of 1 instead of 25 it COULD work. on a good computer
)