Bolt HeadcFitting Question

[Surpmil]

Yes it was mine.

As you can see you can have a number '0' that is larger than a number '3' so specifying I want a 'number 3' is pointless, it is important to specify the actual measurement you need.

Just to clarify slightly Togor, if that's needed: the reason bolt heads can be found with such widely varying or inconsistent measurements relative to their marked lengths is mostly due to previous grinding and lapping by owners or armourers, rather than poor QC in manufacture.

Generally speaking you can be pretty confident that the 0,1,2,3 size marking does indeed reflect a longer bolthead, but by exactly how much? The original size difference was 0.003" between each number.

Civilian owners including myself, tend to want the bolt to just close over the "0.064" GO gauge, but anything between 0.064" and 0.074" was considered acceptable so there was little need to grind boltheads unless as the manual says, the bolt would not close over the 0.064" GO gauge.

There's really no substitute for the correct gauges.