Today we went to the hills to compare two breech plug. Bullet velocity from each plug was measured. One plug is sized for a vent liner with a 3/8" head, and has a 5/32" flame channel. The other is sized to receive a vent liner with a 5/16" head, and has a 1/8" flame channel. Both vent liner have a 0.028" flash hole.













The clock ended up about 14 yard out. Rifle used was the V2; load was 270g Deep Curl, 110g BH209, green Harvester sabot, and STS primer. Powder was dispensed into tubes by Redding 3-BR measure.