For a bottom line you will need:
- Tippmann A5 ASA.
- 2 Macro Fittings.
- 12" of macroline.
- The male adapter from a remote line (aka a Reducer). Commonly available for around $5 (give or take).
- Bench vise/A grip rivaling the Incredible Hulk.
- Teflon seal tape or Loctite.
- Remove male remote nipple from the Reducer by wrapping a couple rags around it and clamping into the table vice, and then removing it with a wrench or a long socket.
- Replace the nipple with a macro fitting, don't forget to use the loctite/teflon tape.
- Repeat step 2 your A5 ASA.
- Attach the parts to the marker, and cut your macroline to your desired length.
And before you know it, BOOM goes the dynamite, you've got a bottomline on your MK3.
Hope this helps.