Scott,
I think this material has been discussed before, but under different circumstances.
As with any of these bronze materials, unless you know the exact makeup of the alloy it is very difficult to know how to machine it, as each mix usually requires a different machining technique. Some requiring a fast and heavy cutting action, others need to go as slow as possible to get thru the material.
I have aluminium bronze in my boxes that machines just wonderfully, and I use it mainly for making pistons and bigs ends. I used the same material for making the tapered gibs in Darrens lathe. Another mix of alibronze, and you could get the same problem as Darren is encountering.
Most of the special mixes are made for doing a specific job, and are not really suitable for general model engineering jobs, unless you are lucky, like myself, and find a load of good machinable material at a super low price.
In my honest opinion, if you are going to invest a little cash in bronze, do so on the known alloys, that are known to be easily machineable.
In the UK, that is generally recognised as PB1 or Colphos, which are versions of normal bearing bronze, not ali bronze.
John