I'm considering about getting back to the field....but first

Okay, so before getting back to the field, I was considering about getting a new rifle that's easier for me to carry
Since I'm going to live at smith landing this semester.
I've considered about ARES AM-013 "not" honey badger, but the "integrated suppressor" is complete hollow
So the inner barrel doesn't seems stable for me.
Then I started to think about HK416C or HK416CQB but the prices for these two are too high
So I hope I can get an EBB rifle meets these requirements:
-full metal body (If possible)
-Short barrel or folding stock (Still can't be too short to play in our field)
-easy to find replacement parts
-AR15 platform
-Cost around 300 dollars (could be a little higher, lower than 350 maybe)
That's all, any good advice? If there's no I think I will still use my old rifle

So I've narrow down the choice to these too（forget the folding stock）
http://www.evike.com/products/52550/
http://www.evike.com/products/41216/
Still.......not sure which one to choose