I tried googling but that turn to crap real fast, so I came here. Are there any certain rules or what not on storing your guns at a different house location then yours? 

Well my first move would to be keep it off the internet.

No nothing bad on why lol...A friend of mine asked me because I have been shooting longer then him (he just started) and he didn’t know. Something is going on currently dealing with family so that’s why. He didn’t know if someone could store for him, or if he would have to see if paying a LGS rent to store it. 

Long guns or pistols?

https://www.gunsitters.com/index.html

If long guns as long as they are inaccessible to anyone else (meaning locked) that should be fine. Pistols not so much.

I believe 1 shotgun and 1 pistol, I’ll find out for sure.

Depending on how "serious" this "thing" going on at home, your friend may be better off selling the goods. Next best thing is to rent gun storage in FAR away places like PA and have a receipt. 

If its not serious things, he is concerned about someone illegally accessing his firearms at home, local LGS is the way to go. 

Not long ago someone posted a bitter case of divorce and some of the things the poor dude had to do in staying clear of being accused of abuse. NJ is a crap place to be caught up in something like that with legal firearms. 

 

I am not a lawyer, dont pretend to be one and not implying anything serious going on. Just 2cents. 

The long gun he could "sell" to you with a COE. Pistol is another story.

5 hours ago, Danno said:

Well my first move would to be keep it off the internet.

And make sure I pay the rent at the self storage place

I would not consider self-storage units in any way secure for firearms storage: http://www.nj.com/middlesex/index.ssf/2017/01/police_probing_possible_connection_of_storage_unit.html

Gunsitters is the way to go.  I believe some local ranges also have storage lockers available for rent.

Not sure what the situation is, but all it takes is for someone (she) to say "he pointed a gun at me" even if it's not true then your life will be upside down.  Best to have a documented way to show you did not have possession of said firearm.