expansion chamber and new barrel (current barrel is 10")
quite accurate for an M3 very affordable as well as durable and low maintanance
a little heavy and cumbersome, not the best barrel
I have used this gun many times and whithout disapointment. It out plays most simalar markers and is very fast for a simi-auto (trigger pulls at about 7 bps) and reliable (I've only broke 2 balls in 6 mo). The hard case is of good quality and has room for adons. I would recomend it to anyone who wants a good, reliable, entry level marker for under $75. --------======O)
If you are looking for a good entry level marker and don't want to pay a lot, buy it! Its fast, reliable, accurate, and durable as well as inexpensive.