What are the pros & cons on using a 308 buffer & spring in a 223 AR15?

[goldfish]

Someone suggested to try using a 308 buffer & spring in my 223 AR15.  It works, but is there something happening inside the gun that would cause harm to me or the gun?  

Thank you.

[jrswanson1]

Last time I used one my rifle wouldn't feed from the magazine.  The 308 spring install was not intentional, someone mislabeled the spring.

[kurtm]

Yes you are going to hurt your rifle if it is a AR-10 rifle length buffer in a AR-15 rifle length buffer tube. The AR-10 buffer is shorter and your bolt key will impact the back of the receiver instead of stop on the buffer. If it is all carbine length your fine.