A unique high performance digital video recorder having a number of novel features. The device includes a connecting ring which has a first region which rotatably secures the connecting ring to the first optical component, and a second region which is axially distanced from the first region and enables the connecting ring to be connected to the second optical component. A proximal end surface of a projection of the gas sensor element and a central inner circumferential surface of the metallic shell form an acute-angle clearance. Firearm cartridges and chambers may have radial shoulder configuration that focuses a shockwave below a bullet base to reduce heat loss to the bullet and support bullet retention in the neck for a longer period of time.