[osagebowman]

Sam, if they are aluminum, there will be a number like 1916, 2018 etc. That will be the "spine". Don't quite understand the ins and out of the aluminum but it's got to do with the wall thickness.

The screw in points come in a variety of weights as well. You can really fine tune it by varying the weight of the point and the length of the shaft.
I generally shoot wood, but do have some aluminum and fiberglass shafts.

[Sam Cree]

I just asked the guy for some inexpensive arrows, didn't know they were aluminum until just now, when I looked at the box. Yes, I agree, wood would make more sense for these bows.

Do you make your own arrows?

[TalonDJ]

That number is probably the alloy of aluminum. I don't know the aluminum numbers well. The stuff around 2018 is a normal decently strong grade of aluminum. Can't say much else about it. We did not spend much time on aluminum in materials class. I had to check my old text book toe be sure that was an alloy number. I could be wrong if they are using some dimension number that is close to a normal AL alloy but I don't know of a unit of measure they that makes sense with that number.