saw someone selling some carbon arrows. The arrows had a 1" 2219 footing on the end. What is this all about? What does it do?

thanks

The aluminum arrow footing will strengthen the carbon from busting out during a hard, direct or glancing hit.  Inserts can be driven back into the carbon shaft causing a big fuzzy end on the shaft.  

Another problem can be breakage of the shaft behind the insert.  A longer, 2" perhaps, footing would help in that instance.  The aluminum adds little weight but tuning would be in order as Forward of Center can change slightly.

so how is the whole thing put together?

This is really a topic best suited to Pow Wow:

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