I have the high speed model and wish I had the slow speed motor, you will peen your case mouths less with the slow speed model. Your not tumbling rocks and if you leave the cases in to long when your forgetful you will not do as much damage to the brass.
Just remember the stainless steel media gets rid of the burnt on carbon and the LemiShine makes the cases shine and adds the bling. It might take a bit longer with the slower speed motor but it will scratch and ding the brass less.
High speed damage below.
The faster the tumbler rotates the harder the cases will hit each other and peen your case mouths.
Scratches from the sharp ends of the pins.
Not all media is created equal and if the stainless media has sharp ends they will scratch your cases. Some pins look like they are cut with a dull set of diagonal cutters and have sharp knife like sprue ends. The better pins are cut evenly and some even have rounded ends.
DO NOT forget to tumble your pins all night by themselves to break the pins in and wear down the sharp ends. You may want to tumble some worthless cases first and get a feeling for tumbling times. The amount of cases in the tumbler effects the dents, dings and scratches and I prefer to be over half to three quarters full to lessen this effect.
And these tumblers are great for large batches of brass and getting them sparkling clean.
Just don't tell your wife how you get them dry so quick.
