i just got a rock river and never shot it and went to remove the barrel to put a free float tube on it but its so tight the barrel nut just gets rounded off.   HELP does anyone got any sugestions?

It may not have such a tight barrel nut. What may be happening is if you do not maintain sufficeint pressure of the wrench against the barrel nut. What happens is the weld spring pushes back against the wrench and lets the teeth slip off of the notches on the barrel nut. Also, what barrel nut wrench do you have, the GI 3 prong or the one that encapsulates about half of the barrel nut? Since you are putting on a float tube, even if you trash the factory barrel nut, don't worry about it it gets replaced anyway. What you may want to do if it keeps slipping or you run out of teeth on the barrel nut is to use some big channel lock pliers. Very seldom do the barrel nuts torque much over 40 pounds or so. Some do, but most don't. I have seen some that damn near came off with finger pressure.

I took a Colt 762x39 barrel off the flat top upper. I rounded off some teeth before going to a torch and pipe wrench. I used propane so I didn't melt anything, then used the pipe wrench but didn't jump on it (so I wouldn't crunch it). It turned off pretty easily. Looking back, I probably could have used the standard tool with the torch. The barrel nut's still on the barrel, incidently.

How are you guys holding the barrel firmly enough to be able to put enough torque on the nut to strip the teeth?  I've got a couple of different barrel vise blocks, and the barrels, on the uppers I need to remove, just spin.  I also tried a Brownells barrel vise at a local dealer.  I broke two of the weak 1/2"-20 screws on it before I was able to get it tight enough to remove the barrel nut.  If I can find better 1/2"-20 machine screws, I'll give that another try, but the ones I've tried locally either strip or break before you can get them nearly tight enough.  About the only thing I haven't tried is to put flats onto one of the barrels with a grinder.  That would work, but the barrels I need to remove are the thin A2 profile.z

An upper receiver vise fixture provides all the hold you could want.

You can increase the grip of barrel vice blocks with rosin or some other grip agent if you don't have a receiver vise fixture.

I basically only use my barrel blocks for installing/removing flash suppressors and other threaded muzzle attachments now.

Here are a coupe of unconventional things to try:

- Put the upper in the freezer overnight.  I guess because aluminum and steel react to cold differenty, this will sometimes loosen things up.

- Douse the crack between the upper and the barrel with a lot of CLP and let it sit for day or so.  Repeat if necessary.

Quoted: How are you guys holding the barrel firmly enough to be able to put enough torque on the nut to strip the teeth?  I've got a couple of different barrel vise blocks, and the barrels, on the uppers I need to remove, just spin.  I also tried a Brownells barrel vise at a local dealer.  I broke two of the weak 1/2"-20 screws on it before I was able to get it tight enough to remove the barrel nut.  If I can find better 1/2"-20 machine screws, I'll give that another try, but the ones I've tried locally either strip or break before you can get them nearly tight enough.  About the only thing I haven't tried is to put flats onto one of the barrels with a grinder.  That would work, but the barrels I need to remove are the thin A2 profile.z

www.accuracyspeaks.com/parts.htm

- Put the upper in the freezer overnight. I guess because aluminum and steel react to cold differenty, this will sometimes loosen things up. - Douse the crack between the upper and the barrel with a lot of CLP and let it sit for day or so. Repeat if necessary.

Good suggestions.  That's also what Bushmaster (who a friend bought two of the barrels from) suggested.  I also soaked one in a pan of Kroil for days without luck.   A local gunsmith said Kroil works much better when warm.  I'm not brave enough to try warming a flammable liquid.

I might just have to buy another upper receiver vise block.  I cracked and chipped the cheap plastic one from Bushmaster.  The guy I talked to from Bushmaster said their new block (the one that fits from the bottom) is much nicer, so I might give it a try.

I guess I should mention that these are all 20+ year-old Colts.  A couple of them came from Tapco when they sold parts kits about a year ago.  I spent days cleaning the mud, dried grease, and rust off of those.  This is a lot of work to replace two broken delta rings, a weak spring, and two barrels between five uppers.z