WIN1886, it isn't necessary to take the barrel out of the stock to clean it. One option to clean the barrel is to plug the nipple with a toothpick or some suitable soft round material to make a water tight seal. Hold the rifle upright and carefully pour warm water down the barrel. I usually wrap a towel around the barrel near the muzzle to absorb any water I spill. Let the water soak for a few minutes. Hold your thumb over the muzzle and upright the rifle to slosh the water up and down the barrel. Pour the water out and run a wet patch down the bore with a tight fitting jag. Repeat the water and swabbing with the patch until the patch is relatively clean. Run dry patches down the barrel until the barrel is dry. Run a patch saturated with your preferred rust preventative down the bore. Remove the toothpick and clean around the nipple, drum, breech end of barrel, and lock with wet patch. Dry, oil, and you're done. If you use a petroleum base oil as rust preventative, remember to clean it out with a dry patch before you load for the next shooting session.
Another method is to get a "flush nipple" like this one from Track of the Wolf.
http://www.trackofthewolf.com/Catego...78/1/FLUSH-RST
You attach rubber or plastic tubing, such as surgical tubing, to the flush nipple and screw it in place of the regular nipple. Place the loose end of the tubing into a bucket of water. Put a tight fitting patch on your cleaning jag and run it down the barrel. It should be tight enough to displace air out of the barrel and through the tubing and bubble the water. Slowly pull the rod and jag up the bore of the rifle, pulling water up the tubing and into the barrel. Keep working this pumping action, flushing the barrel with water. Change patch if you start loosing suction. When you feel you've loosened and flushed the fouling out, throw out the dirty water and replace with clean water and repeat the flushing action. I like to add a cap full of Ballistol to this rinse water. It keeps the barrel from flash rusting. Dry the barrel with dry patches and oil it with the rust preventative. Clean drum, breech, and lock and wipe with oil.
If you do want to take the barrel out of the stock to inspect it, you will need a pin punch that is smaller than the diameter of the pin. The pin in the stock is not tapered, but its ends should be rounded so it doesn't catch the wood and splinter out a piece. Carefully drive out the pin. I always drive the pin out towards the left or off side and replace in opposite direction. Don't try to remove the barrel yet!!
You need to remove the lock bolt and the tang bolt because both are holding the breech end of the barrel to the stock. See photo below.
To remove the barrel once the pin and these two bolts are out, you should turn the gun upside down holding it about midway down the barrel with one hand and near the lock area with the other hand. Gently drop the rifle onto a padded surface so that the wrist area hits the padded surface. What you want to do is let inertia loosen the tang and breech of the barrel from the stock. Once the tang is out of the inlet in the stock, then lift the rest of the barrel out of the stock. You do not want to try to remove the barrel by pulling up on the muzzle end. This can turn the barrel into a pry bar and place enough leverage onto the tang to bend it or even break it where it has been drilled for the tang bolt. You also run the risk of chipping out a piece of wood at the end of the tang due to the pressure.
Now you can fully inspect the barrel, tang, drum and nipple for any rust, old oil, or other gunk like on the barrel in the picture above. You can also look for any other barrel markings on the bottom of the barrel.
I think you can see that with this type of breech plug, a key isn't much of an advantage over a pin when one wants to remove the barrel. There is as much risk of damaging the tang or the wood around the tang as there is in damaging the wood around the pin. It can be done without any harm if you are very careful. You wouldn't want to do it for every cleaning, though.
On factory finished rifles, the company logo and address is normally stamped on the top flat of the barrel. The caliber, serial number, and makers mark are normally stamped on the off side oblique flat near the breech. If a customer requested it, the stamps could be hidden on the bottom flats. I have one GRRW rifle like this.
If your rifle doesn't have these stamps, then it was likely a kit that was assembled by the buyer. Some people that bought these kits from GRRW were very skilled craftsmen, often experienced rifle builders, and put together a high quality rifle. Yours sounds like one of these.
Phil