I have decided to convert my 20" Colt Sporter Match HBAR A2 over to A3 config. and I also ordered a bunch of extra stuff for it.  I figure why not go ahead and build the thing completely now.  

I have these parts coming in: upper vice block, DPMS armorers tool, Samson MRFS-R forearm, YHM bipod mount, and a TD VFG coming in.  Already have the complete A2 rifle plus a Colt A3 upper receiver here as well as a Harris bipod.

Now my question is, can I get a couple tips on switching out the barrel on my A2 receiver to the A3 receiver and also installing the forearm?  I'm sure that there are a couple of little tips that will save a headache or two and I'd LOVE to know them.  I've already studied the DIY post on barrel swapping and that entire post is as good as gold, but I'm sure there is some little problem I will run into.

Any of you pros out there care to give a tip or two so I don't have to beat my head off the wall for something simple?

Thanks is advance!

-X

there are tacked threads up above which will help you with all you needs

Hit the barrel nut with some Kroil or other penetrating oil, and let it sit for 15 minutes or so.

If you're lucky, your barrel isn't torqued to 105lbs and will come off easily lol.  

Other than that, it's pretty simple.  

A lot of folks here do not torque the barrel nut...hand tighten it, and then just use the wrench to snug it down 'til the teeth line up so you can get the gas tube in.  If it's still loose, then crank until the next gap lines up.  Repeat until it's good and tight.  When you have it where you want it, make sure the gas tube goes throught the hole in the receiver.  

That's really the only hard part about swapping the uppers.  

I can't help you with the Samson forend...never used one.