Most of the "tiger striped" maple stocks I have seen on old Pennsylvania or Kentucky rifles was maple, a very common wood back east. The grain structure along the trunks of many of these trees shows "fiddleback" grain (so called because it was preferred for use on the back of violins), and they were very much in demand for musical instruments (tonewood) and furniture-making, which made a piece of wood large enough for a stock to be quite expensive. Many fine quality old rifles were made using fiddleback maple for the stocks, chosen for the beauty of the grain pattern. The stocks were often stained with aquafortis (a nitric acid mixture) or permanganate which darkened the grain but emphasized the depth of the grain structure.
As always, people tried to figure out methods of achieving comparable results using lower quality materials. Plain-grained maple, ash, sycamore, hickory, beech, birch, and chestnut wood were often used to make stocks on cheaper rifles, and then stained and finished to try to look like high-end rifles. One of the things people did was to put a dampened piece of wood in a barrel full of scrap pieces of iron or steel (which would give an irregular staining pattern), or wrap cord around a stock and scorch it over a fire to produce darker stripes in the wood grain (similar to the process used to produce "roasted" birch and maple that look like walnut). I was even taught a method for "painting" figure into wood using different solvents and finishes. In 30 years, I have heard dozens of recipes for producing "tiger-striped" maple, usually from people who have little or no experience working wood. I have never heard of or seen a recipe that can produce the quality people look for, and most produce very poor results.
The best method I have found is to find a wood dealer and buy a good piece of fiddleback maple. It is widely availble and relatively inexpensive when you figure the cost of chemicals and/or different supplies used to try to fake it.