Fully Supported Chamber Question
- Thread starter Benito
- Start date
In a fully supported chamber, the chamber has metal surrounding the
entire cylindrical wall of the case of the fully headspaced round. The
spent case expands outward, evenly.
In an un-supported or partially supported chamber, part of the case's
side wall are not backed by metal.
Take a factory Glock barrel. When the round headspaces, there is a
small section of side wall brass visible at the rear, right above the
barrel's ramp. This section is "not supported". The brass will expand
out a little more here, hence bulgy brass. These bulges are difficult
to remove without full length case resizers or roll sizers.
Over time, if you continue to use fired more than once brass, powder
may burn thought this unsupported area of weaken brass, causing
KABOOM.
This is not limited to just to factory Glock barrels. Any un-supported
barrel risks this sort of failure.
entire cylindrical wall of the case of the fully headspaced round. The
spent case expands outward, evenly.
In an un-supported or partially supported chamber, part of the case's
side wall are not backed by metal.
Take a factory Glock barrel. When the round headspaces, there is a
small section of side wall brass visible at the rear, right above the
barrel's ramp. This section is "not supported". The brass will expand
out a little more here, hence bulgy brass. These bulges are difficult
to remove without full length case resizers or roll sizers.
Over time, if you continue to use fired more than once brass, powder
may burn thought this unsupported area of weaken brass, causing
KABOOM.
This is not limited to just to factory Glock barrels. Any un-supported
barrel risks this sort of failure.
The more the cartridge is hanging above the feed ramp in the "in battery" position, the less support it is said to have. In the picture below, HK and Springfield have fully supported chambers while other pistols have partially supported chambers, with Glock 22 having the least amount of support.
