Abstract: A reducing agent metering system for delivering reducing agent to a lean burn internal combustion engine. The reducing agent metering system includes a metering system housing, a system for metering vaporized reducing agent to the internal combustion engine, the system positioned within the metering system housing and a system for delivering an atomized stream of liquid reducing agent to the lean burn internal combustion engine, the system positioned within the metering system housing, wherein the reducing agent metering system is operable to transition from metering vaporized reducing agent to delivering an atomized stream of liquid reducing agent to the lean burn internal combustion engine.

Abstract: A muzzle loading firearm has a barrel with a bore on a bore axis, and the barrel has a muzzle end and a breech end. A frame is connected to the barrel, and has a breech face. The frame moves between an open position in which the breech face is away from the breech end of the barrel, and a closed position in which the breech face abuts the breech end of the barrel. A breech plug is removably attached to the barrel. The breech plug including a seal element closely received by the bore. The seal element may be a set of piston rings that are received in a circumferential groove about a forward end of the plug, or may be a cup at the forward end, with a forward rim that flares under pressure to provide a gas seal.

Abstract: A muzzle loading firearm has a barrel with a bore on a bore axis, and has a muzzle end and a breech end. A frame is connected to the barrel, and has a breech face. The frame moves between an open position in which the breech face is away from the breech end of the barrel, and a closed position in which the breech face abuts the breech end of the barrel. A breech plug is removably attached to the barrel, and is connected to the barrel by way of interrupted, or multistart threads, or locking lugs. The breech plug may have a rear face that abuts the breech face when the frame is closed, so that a primer contained in a primer pocket in the rear of the breech plug is fully supported on all sides.