The air rifle gauges DO have a rim but only small. The same one serves 6yd and 10m because the rings are the same spacing.
The .177 gauge does not have a rim and is for outer ring flyers.
I am a club scorer and the four NSRA gauges are essential because different power weapons and variable cards give varying hole sizes.
Download the NRSA scoring guide pdf.
Generally you should not gauge your own cards if they are postal cards to be sent off as already stated. When any shot is gauged you must write next to it G+ or G- depending on how the decision went.
Targetscan is good on iPhone not so good on android. Also with 5 spot rifle cards you need to scan each shot where pistol will scan up to 10 shots, so PIA for rifle.