Can I mix chapters with the Space Marines?

Ok, so I'm new to Warhammer 40k. I play with a Space Marine Army. I notice that there are several chapters (Dark Angels, Blood Angels, Ravenwings, Black Templars, etc...). Some of these even have their own codex. Can i buy some of these and just mix em with my regular space marine army or are they a separate force by themselves? I'm confused.Can I mix chapters with the Space Marines?
There's different answers depending on what you want to do.



Marine armies (also called MEQ for "Marine Equivalent" or PA for "Power Armored" armies) have several different rule books representing different groups. Dark Angels, Blood Angels, Space Wolves, Black Templars, and Space Marines (for the Ultramarines and pretty much everyone else). There's also Chaos Marines for the 'dark side' version. Each of these are separate rules sets, which you generally can't mix and match. There are exceptions, such as in Apocalypse games and other times when you and your friends decide you don't care about such restrictions. But generally you should only be using one codex at a time.



HOWEVER...



If you just want to paint your figures to look like they come from different chapters (like in a "Crusade" army) but only use one set of rules you shouldn't have any problems as long as you make it clear to your opponent what set of rules you're using.



or



Since so many of the rule sets are pretty similar and use the same base figures and vehicles, with a little planning and limited swapping out you could build a collection of figures that you could use with different rules sets, one at a time. Tuesday play as Dark Angels, Thursday as Blood Angels, Saturday as Space Wolves, etc. Again, just make it clear to your opponent about what rules you're using and what figure represents what if it isn't obvious.Can I mix chapters with the Space Marines?
Yes you can so long as the other marine units appear in your Space Marine Codex.



So you could have a squad of long fangs and another of Blood Angels, but the squads would have to conform to the rules of the normal Marine Codex and not the rules that appear in the Space Wolves or Blood Angels codices. You also couldn't use units that only appear in the other marines codices like the Furioso Dreadnought. You could however use a bunch of Space wolves sitting on giant wolves as a "counts as" unit for space marine bikes, but obviously you'd need to tell your opponent at the start of the game what they were.



You can of course have a "Blood Angels" army using their codex but paint them all as Ultramarines, it's up to you. The main thing is just using one codex at a time.Can I mix chapters with the Space Marines?
They are seperate armies and you cannot mix them but generally they are the same with only a few slight differences. The chapters are just specific forms of space marines who get some extra rules and stuff. You can use the chapter models as regular space marines. You can also use your regular marine models as the specific chapters with just some color changes.