What portion expands during firing to aid the rotating band in creating an airtight seal to prevent hot gases from escaping?

What portion expands during firing to aid the rotating band in creating an airtight seal to prevent hot gases from escaping?

• A. Fuze Well
• B. Obturating band
• C. Rotating band
• D. Eyebolt Lifting Plug

Answer: (D)

Gas seal in a projectile is achieved by the obturating band. When the propellant gases push behind the projectile, this band plastically deforms and expands to fill the bore gaps, creating an airtight seal that keeps hot gases from blowing past the projectile as it moves. The rotating band’s job is to engage rifling and impart spin, but the expansion that prevents gas escape comes from the obturating band. The other parts mentioned have different roles—fuse components house the fuze, and the eyebolt lifting plug is used for handling—and they don’t expand to seal the bore.

Gas seal in a projectile is achieved by the obturating band. When the propellant gases push behind the projectile, this band plastically deforms and expands to fill the bore gaps, creating an airtight seal that keeps hot gases from blowing past the projectile as it moves. The rotating band’s job is to engage rifling and impart spin, but the expansion that prevents gas escape comes from the obturating band. The other parts mentioned have different roles—fuse components house the fuze, and the eyebolt lifting plug is used for handling—and they don’t expand to seal the bore.