Brett: You can remove most finishes using Acetone. I understand that is the chief ingredient in many of these modern paint removers that look like a paste. They work, but they are only a more stable form of acetone. Use this stuff in an open area, with plenty of ventilation. Don't breathe in the fumes. Its nasty stuff!
But, that having been said, I have been around a lot of equally nasty stuff you don't want to inhale. The best part about using acetone is that its available from most paint and hardware stores, or home building supply stores, its relatively cheap, and it removes ANY FINISH that I have heard about. I used a brush to slap the acetone on a stock that needed refinishing badly. I started at the top, letting the acetone drip down the wood into a metal tray I had to catch the drippings. I had expected to have to wait several minutes, then brush on more, then wait, scrape, then put on more, etc. until several hours later I would have all the finish removed. NOPE! The finish began to bleed off as the acetone touched it! I actually ended taking broad strokes down the stock to wipe off the finish as I was wiping on the acetone! I had that whole stock stripped in about 5 minutes, and probably less.
Of course, not believing in my good fortune, I dried the stock, let it dry some in the sun, and then went it again with acetone. ( Doubting Thomas, ME!) The acetone hit the tray as clear as when it left my brush. With the first pass, it removed old dirt and varnish, or whatever oil finish might have been put on the stock, from deep in the grain of the wood.
On another project, the factory finish included a " walnut " Paint over Birchwood. The acrylic? finish and paint all came off with the first brush strokes. The birch stock was actually not bad wood. I highlighted the grain with some cherry stain, then stained the wood with a commercial alcohol walnut stain. Then I hand rubbed Tru-oil into the wood to finish the stock. The owner of the gun did not even recognize the stock!