did you put the mod in the right folder? pressing subscribe only downloads it to Steam>steamapps>workshop>content>304930. Thats good but only for single player and joining modded servers. If you are running a server then copy the mod to Steam>steamapps>common>Unturned>Servers>(your server name)>Workshop>Content.

Another problem that might occur is that you do not have the "Laser Muzzle Effect" mod because this mod can't work without it. just subscribe to it and your good for singleplayer but if you have a server copy it from Steam>steamapps>workshop>content>304930 and move it to Steam>steamapps>common>Unturned>Servers>(your server name)>Workshop>Content. and your good to go, enjoy!

Another possible problem is interfering ID's from other mods, this occurs when two mods each share the same item ID's so the game doesent know wich one to give you so it doesent give you ether item at all. In other words having 2 mods with the same ID's would cause thoes ID's to be unusable. If you have another mod with an interfering ID you can either

A) delete the mod and unsubscribe to it that way you can use this mod
or
B) Change the interfering mods ID's or this mods ID's.

Now there are pros and cons to both of these methods but there the only ones aside from asking the owner of the mods to change the ID's and redownloading it wich also has some cons.

The pros and cons for A are as follows:

Pro
you can use this mod in both single player and when entering servers.

Con
you are throwing away another mod that you might like just as much as this one.

The pros and cons for B are as follows:

Pro
you can use both mods without the need to delete another mod you may enjoy.

Con
you cant join servers with the mod that you changed the IDs of because your IDs dont match the servers ID's so the server looks at as if you had another mod and not the mod it really is.

Now the process for A is quite simple but for B you have to know what your looking at.

with A you just need to go into Steam>steamapps>workshop>content>304930 and delete the mod, but first you need to know the ID because the folders are named after their IDs. to do this go to the page were you downloaded the other mod and look in the URL bar at the top left and the large string of numbers after the line "/?id=" is the item's ID. then just find the number in the 304930 folder that matches the ID in the URL bar and deleat it (Note that if you have any servers delete it from there aswell by finding the ID in the same way i just explained then going into the servers workshop>content folder and deleating it)

I dont reccomend going through the process of B if you plan on hosting or joining other servers which face it, its the only thing that makes the game any fun at all but if you want me to explain it just ask.

if you have any questions or require further details or instructions just ask and ill be happy to help. :D