Tiger striped maple (as well as birdseye) is not really a result of being cut near a limb. You might get a "burl" effect the same way as you do on other species that are cut from stumps. An entire tree can be "tiger striped" or "fiddle back" as it is sometimes referred to. There are a variety of species of Maple and all of them can produce wood that contains the striped figure - it all depends on the tree. I have ask botanists and have never received an answer as to why one tree may be that way and another isn't. Regardless of it is soft maple, or hard maple, sugar maple or red maple, etc. . . . it is something that just occurs in nature. It doesn't seem to matter if the tree has a wet environment or a dry environment either.
I have also worked on original long rifles that have had a "faux" tigerstriping applied to a rather straight grained stock. This was applied in a variety of different ways by the old stock makers which is a whole other subject.
OP - are you talking about an "antique" rifle or one that is custom made? I'm guessing that what you may have seen was actually a "faux damascus"? I have run across several custom rifles over the years that had barrels such as I think you are referring to. I've seen one that was browned and several that were blued. My guess is that it was done by possibly wrapping a cotton cord around the length of the barrel and saturating the cord with a cold blue or a browning solution. At the point of where the cord touches the barrel, the solution (in theory) would be heavier than the space between the tight wrapped cord that was formed by the radius of the cord. You might try experimenting and try different methods like that.
I believe that what you are referring to is nothing more than a "faux" finish - not unlike what is sometimes done with blue to creat a "faux casehardened" look.
If a pair of '51 Navies were good enough for Billy Hickok, then a single Navy on my right hip is good enough for me . . . besides . . . I'm probably only half as good as he was anyways. Hiram's Rangers Badge #63