i will have to add my recommendation for arrow arms out of macon, ga. i bought a new -m4s that had never been fired second hand. i proceeded to try it out and on the 10th shot the gas seal on the bolt came loose and locked the bolt in place. i emailed the factory about 10 pm and the very next morning around 9 am they called. they immediately sent a gunsmith tech out to the closest dealer. i drove a few miles to the dealer and within 10 minutes, he had it fixed, gave me his personal cell phone number and said that if i had any further issue, give him a call directly. this is the kind of customer service that will get me to buy more of their rifles. if you want a company that will chase you down to fix any issues you might have, i would checkout http://www.arrowarms.net/aarms/ .