The design of these new PWR inserts is different to those you are previously familiar with. They are a very close tolerance to the barrel back, and yet can still be removed easily. The muzzle end has an external chamfer to promote the best alignment with the barrel front possible. They have an internal chamfer and radius ball entry lip, not a sharp edge, so are super gentle on the paint. They are marked with bore sizes that can be easily seen without removing the insert from the barrel back (and can also be identified by the colour as seen through the rearmost ports on our barrel front. The inserts are easily gripped and removed from the barrel back.