Hello. I need some help. I have a Bushmaster upper receiver that has a BMAS Carbine forearm (actually it is made by Yankee Hill Machine company secure.valinet.com/~yankeeh/cgi-bin/web_store/web_store.cgi?page=forearm.html&&cart_id=2864642_24290). I have purchased an ARMS #45C SIR forearm to install on this upper. I have to replace the BMAS barrel nut with a standard barrel nut and install a Delta ring assembly. I have purchased a vise action block to secure the receiver assembly and also a combination barrel wrench from Brownell's. I know that I will need also some moly lube for the threads on the nut. What I need now are suggestions and recommendations on anything else that I need or may need. This is the first time that I am removing a barrel but I am good at mechanical things so I shouldn't have trouble in that area. I just need someone to check me to make sure I haven't forgot anything. Thanks.

You want to tighten the barrel nut to about 35 ft.lbs.
Jack

I use a torque wrench.  You can get them at an auto parts store for $20 or so.  You want somewhere between 31 and 80 pounds of torque.

You will need a punch to get the little pin that hold the gas tube.  It can sometimes be a PITA to get the pin back in, so make sure everything is lined up perfectly.  It helps to have a set of specialized punches for the job that Brownells sells.

Be sure your Moly does not have graphite in it.  A lot of commerical antisieze does.

If you have a tough time getting the nut off, stick the upper in the freezer overnight.

Getting the gas tube off can sometimes be tough.  I have not found a perfect solution, but just apply CLP and wiggle it.

When you get the gas tube back on, stick the bolt carrier in the reciever to make sure the gas tube is not a little torqued and nicking the carrier.