Re: RCBS Precision Mic
I have used them, and they require a certain amount of 'feel' if you will. Read the instructions. This time it is important to do so, and it may just keep you from ruining it.
I set up my 300 WM dies with one, and then double checked everything later when I bought the Stoney Point stuff, and I got the same readings.
The RCBS is a more expensive way to go, but it does work fine.