I am planning on buying a carbine for 3 gun shoots, home defence, and plinking I am seriously considering the LR300M/L. I am issued the M4 and have access to HK53,HK36K+C,Sig 551+552,and a LR300 I've shot all of them finding I like and dislike different parts of each wpn but I need to keep my muscle memory with the AR/M16 so the LR appeals to me IF the operating system is solid and reliable. I don't have time at work to put the LR that we have thru it's paces so I'm looking for feedback from some of you who have put 30K + rounds thru one. I have noted some other threads mentioning problems with the return spring overheating and getting to weak to cycle after sustained fire, is this a problem that happened with earlier models or is it still an issue?