Originally Posted by defjon
I was also wondering if anyone knows a way to remove the bit of wood that makes it only accept 3 shells.
If the round knob at the front of the mag tube is removed (usually to slide the barrel off), there'll be a circular spring cup inside the end of the magazine tube, which holds in the magazine spring while the knob's off for cleaning, etc.
Use a screwdriver, inserted partway into the slot where the ends of the spring cup don't quite meet, to gradually work the cup out of the end of the mag tube - keeping in mind that it'll be powered by that magazine spring when it comes almost all the way out.
After it's out, the dowel inside can be slid out, too.
Then, stuff the mag spring back into the tube & hold it in place with the tip of that screwdriver while you reseat the spring cup back into the end of the mag tube. (It's OK to tap/hammer it fully-seated).
You're done, except for re-installing the end knob ( and barrel if you removed it).