There are numerous ways to measure shoulder bump without using a Precision Mic. Use any one of them? Drop a pistol case on the shoulder and use calipers, for one. It works, as do many other ways.
I had a Precision Mic for while, a long time ago. I didn't find it particularly great and gave it away. Lots of guys have been getting quite good results from their rifles without them for a very long time. Including for a very long time before the Precision Mic even existed. If it fits your reloading habits and you like it, great, carry on, but, it's hardly needed to obtain excellent results.
Just my opinion...
- DAA