buffer rattle

[62flint]

I just picked up a used Grendel. It is a 16inch AA upper on a rifle stock double star lower. First thing I noticed was the buffer rattled. Like something is loose inside of it.
I have not noticed this before on any other of my ar's . Any thing to be concerned about?
I have not shot it yet so I do not know how it functions.

[ricsmall]

the buffer has weights inside that will rattle. I have noticed it on some of mine, others I dont.