I am not a gunsmith and this is not a substitution for professional gunsmithing services. Use at your own risk.
These are the British armourer's spec.
Go - 0.064"
No-Go - 0.068" - not really used
Field - 0.074"
They can be used with any .303 Lee-Enfield. If your bolt closes on the Field gauge then it has excessive headspace. At minimum, you should feel resistance at about a thumb's width between the bolt handle and the receiver in order for it to pass the Field gauge.
Make sure to check your gauges with calipers before using them. If your prints are undersized according to the above, reprint at 101% and then lightly sand on a flat surface.
This video explains how they're used.
| Lee_Enfield_303_Headspace_Gauge_-_Field_v6.stl | 32.7KB | |
| Lee_Enfield_303_Headspace_Gauge_-_Go_v3.stl | 52.8KB | |
| Lee_Enfield_303_Headspace_Gauge_-_No-Go_v4.stl | 32.7KB |
