Measuring primers can become tiresome. One approach is to learn the average length of a primer brand. Once one learns the average length of a particular brand of shotgun primers, one can establish a length for the breech plug. A breech plug can be purchased to fit one's rifle, and a brand of primers. The breech plug is made so it 'crushes' the chosen primer brand, which eliminates blow by.
The average length of CCI primers, and Federal 209A primers is about the same. It is also true the average headspace of all Omega rifles is about the same. One can purchase one breech plug for all of one's Omega rifles, and for every box of CCI, and 209A primers.
At one time one could use OEM Omega breech plugs, and the longer W209 primers, and achieve enough 'crush' for blow by free shooting. At one time about half of W209 primers worked without blow by in Omega rifles using OEM breech plugs. It seems anymore W209 primers don't often 'crush' using an OEM breech plug.
Currently this shooter has one Bestill Creations breech plug sized to use CCI, or 209A primers in Omega rifles, without measuring. One can also use shorter W209 primers in this plug, and rifles, but one must measure to find usable W209 primers.
Currently this shooter has one Bestill Creations breech plug sized to use CCI, or 209A primers in a Knight Ultra-Lite, without measuring. One can also use shorter W209 primers in this plug, and rifles, but one must measure to find usable W209 primers.
Currently this shooter has one Bestill Creations breech plug sized to use Remington STS primers in Omega rifles, without measuring. STS primers are almost all the same length.
Having things set up so there is zero blow by is nice, quite nice.