Oo er! Frame has got a BB in so that's not an option. Had a look on the columbus tubing chart and the steerer tube of SL tubes had rifling too. Maybe a torch down the seat tube?
not sure if the steerer tube would have the rifling.
putting your finger in the bottom bracket and reaching up the seat tube seems to be the accepted method.
Oo er! Frame has got a BB in so that's not an option. Had a look on the columbus tubing chart and the steerer tube of SL tubes had rifling too. Maybe a torch down the seat tube?