I was in the same boat this year, trying to decide which reciever to go with. Yes, you might be better off in the long run with a steel reciever if you are going to pound thousands of rounds or run hot handloads through it each year but most HUNTING rifles probably won't see that many rounds in your life time, some will but most won't. Also, I thought about the other firearms that I have that have aluminum recievers or frames and the fact that I will and have put more rounds through them than I will probably ever put through my .308 LWT so far without failure (bushmaster AR-15, Sig p220 .45, Sig p229 .40), and the reputation of these firearms I believe speaks for themself. I like the feel and the balance of the LWT with the 20 inch barrel, I agree that the weight savings isn't that significant but I still like the LWT better for my intended purpose of having a semi-auto. If browning made a steel reciever with a 20 inch barrel then I probably would have opted for that instead of the LWT. I also agree that if you were going to get a magnum then you would definately want to get the steel reciever. I also feel that if the aluminum reciever was going to pose a problem that browning would not manufacture them (aleast I hope so). So far I've shot less than 50 hand loads throught it, so I can't speak about its durability yet but I am very confident that it will last me a life time, not mention that it shoots real well. If in doubt then go with the steel, like RRH said, the steel recivers have been proven over time to be durable.

If you're not huntin' you're not livin'!!!!!!!!