I have a choke tube that is rusted in the barrel. the gun is an remington 870 express magnum. any ideas on getting it out would be appreciated.

put the gun barrel down in a container with Kroil oil in it, that Kroil is the best stuff there is. I would let it soak over night. I would then get a hair dryer or preferably a heat gun. Wipe the excess oil off and out of barrel. Carefully warm barrel up on the outside of the barrel around the choke threads. not red hot, but you want to get it pretty warm.

At 130-140 deg F, you will not be able to hold your hand on it for more than a split second. Try to get it around 175 deg F

The fast er you can warm it the better and immediately try and uncrew the choke. If it starts moving, go with it. If it stops then dont force it. Let everything cool off and repeat with the oil and heat.

Make sure you are using the socket type wrench and not the flat type and do what fastliberator says.

If it is rusted as bad as you say, you may need/want to let it soak longer, using the tube wrench to apply tension back and forth for a couple of days prior to the heat treatment.

I've had this problem before. After you soak it, actually tighten it a little before you try to loosen it. Sounds counter-productive, but it's a tip that was passed on to me and has worked.

Not to be a smart a$$, but have seen guys trying to take them out by turing them the wrong way. Righty- tighty and lefty- loosy.

That's a good tip.

And if/when you get it out, put some anti-seize on the threads of the choke BEFORE you put it back in! Anti-seize would have prevented this problem from happening. Heck, any type of automotive grease applied liberally to the threads would have prevented that. I realize you might have gotten the gun 2nd hand and this might not be your fault.

You can get anti-seize from any auto parts supplier. It works.