I just did two drums yesterday. Used my jigsaw with metal cutting blade. Took all of 5 minutes and only left about 1/16 lip inside. Used 2 hammers backed up and flattened the 1/16 to the wall. Took all of 10 min. total.
Jeff - KCBS #67908
Custom BQ Grills Vertical Smoker (SOLD)
WSM 22.5 (CL find)
Charbroil Bandera (Free from fellow Brethren!!)
UDS x 2
BQ Grills Patio