When working up powder charges, using this micrometer metering insert will save you a bunch of time.
Prior to adding this, it took many tries (trial & error) trying to increase or decrease the powder charge by turning the knob in or out.
With the addition of this metering insert, it makes the adjustment much quicker and more accurate, saving you time and aggravation in the process.
I consider it a must have, especially these days in limited component availability. Instead of using one certain bullet type/weight, you may need to try others due to availability, and this insert makes changing the powder charge much easier.
Pros: Easy to set and use
Cons: none that I can find
This review was written in the old system and had content requirements that are different than reviews written today.