Depends on how strict you want to be with your rifles.
For instance the MN's were routinely checked and passed with the field gauges because they were being checked in the field by the armorers. They considered it to be safe to shoot if it passed that gauge.
A lot of them that are safe to shoot will fail the no go gauge.
Well guys, looks like you have the choice of field or no go. You aint gonna get any better than that.
A bullet will do the same thing as a go gauge, if the rifle will close on the shell it just passed the go gauge
It is important to check your rifles though, my Romak 3 blew a couple of primers, and when I checked it with the field gauge, it swallowed it and I had to send it back in for repairs, and this was a "new" rifle assembled out of used parts.