I removed mine (with care) large tip screw driver and using a small rubber mallet to give it little taps here and there and just wiggled it off.
As long as the screwdriver is used only for taking out the screws I agree....
DO NOT use it to pry the plate off!!!!!!!
When working with a bringback go slowly and carefully. Take your time and do it RIGHT! Try to be in a hurry and you can seriously hurt value.
Here is what I do...
***Remove screws with a well fitting hollow ground driver.
Don't have a hollow ground driver....stop right here, and get one. Ill fitting drivers cause 98% of all buggered screws.
***If you are worried about the driver slipping from a really tight or worn screw head place some duct tape (on metal only) to protect it from a slip and scratch.
***Wood that has gotten damp or stored in a damp place like a basement or garage will often expand some. This expansion can really make a b-plate a bear to get off sometimes. If the stock is damp, or been in a damp place it might be best to let it dry a few days in a warm dry place before trying to remove buttplate. I have a shelf near my furnace I use. Not too hot though....a dry 80 degrees is nice... if you can't do that...put it on a dry surface and run a fan blowing gently on it for a day or two. Turn over every now and then to get other side. Sounds silly I know...but can help greatly if you have a damp stock.
***With screws out, try moving the plate. Sometimes they will come right off.
***If it will not budge enough to get it off by hand, but is loose, then you can try tapping the plate off, or using a punch to hook the screw hole....here is how to do both...
*****Start with a small punch or drift...Use a punch a tiny bit smaller than the screw hole in the plate. Start on the top hole as you want to work the plate off from the top due to wood shape as mentioned previously. Put the end of the punch into the top screw hole... by wiggling this it will give you some leverage to pry the plate when you put pressure on it.
You are not using it to pry against the wood underneath the plate! This sometimes will be enough to get the plate moving.
If it does start to move then work the plate back and forth a little at a time to get both top and bottom of plate moving. Don't take the plate off completely from the one screw as angling the plate too far in one direction can mess up the wood.
*****If this gets the plate started but not all the way off then you may tap on it. I like to wrap the rest of the stock in several layers of an old towel to protect it from slips...get a friend to help you hold everything if need be. (Remember...go slow always!) Use a block of wood against the b-plate...never steel, or other things. The wood will not mar the metal, metal objects can mar it easily. Remember to hold the block away from the wood stock as much as possible when tapping...even wood can dent your stock! Better to tap many small blows than one big one. Again work slowly from several angles to walk the plate off from top to bottom a little at a time.
***This should get the b-plate off. It might prove interesting....sometimes makers marks, and things can be found under the plate on the wood. The inside of the plate will often be painted, and often have ink stamps and things. Have fun...work slow, and congrats on your new finds!!!