It took awhile, but finally found photos of a CVA breech plug that will reliably ignite Blackhorn.











The plug on the left is the OEM CVA plug, which is unreliable igniting Blackhorn. The middle plug will reliably ignite Blackhorn 100% of the time using any shotgun primer in -15 degree temperatures or warmer; every time, all the time, any time; it fits CVA rifles. The plug on the right is the OEM Omega/Encore plug, which reliably ignites Blackhorn every time, all the time, any time, using any shotgun primer.











Note, none of these plugs has a vent liner.

Just in case anyone is interested in some specifics, the middle plug has a 0.028" flash hole, and a 5/32" flame channel; works perfectly in my old Accura, and has been tested a jillion times using W209, and STS primers. Many a night when the forcast was for sub-zero temperatures i loaded the rifle, and put it in the truck, so i could see how it worked in the morning. The old rifle never failed to fire right now, right away, using the W209, and the STS primer, no matter how cold the night, or morning.

The vent liner is not necessary for igniting Blackhorn. However, when using the highly erosive shotgun primers, the vent liner has the advantage of allowing the flash hole to be replaced quite economically