Love these as they do indicate an empty chamber without having to use a chamber flag which can force crap into the chamber/breech. Excellent fit and easy to see.
I have now printed 5 of these chamber blocks. I am using a Creality Printer. I used Pura Slicer for the G Code. I did a 30% infill with 4 Outside layers and 4 bottom and top layers. I am using Amazon PLA filament. I print at 200* tip & 60* Bed at 80% speed. The chamber block has fit the Bergara HMR Stock, Grayboe Ridgeback & MDT ACC with ease. It is a solid lockup and stays in good.
Printed as directions stated and fit and worked perfect in my Bergara B14R.