Adjustable carrier
Disclosed herein is a modified rifle bolt carrier allowing a selectively openable vent/valve at the location where exhaust gas is pressurizing the bolt carrier to control carrier speed under suppressed fire in a first valve position or unsuppressed fire in a second valve position. A valve core is disclosed which may be rotated 180° to a first “open” setting for non-suppressed fire from its position in a “closed” position for suppressed fire, and a third “median” position. The modified bolt carrier will allow an operator of the firearm to adjust for a suppressor without changing the gas block or having to modify or adapt the front end or barrel end of the firearm.
1. A firing assembly for a firearm, the assembly comprising:
a bolt carrier having a longitudinal axis, a surface defining a gas port;
the gas port configured to be in fluid communication with a gas block forward of a chamber of the firearm via a gas tube when the firearm is assembled;
a surface of the bolt carrier defining a valve housing within the bolt carrier, the valve housing intersecting the gas port;
a valve core having an outer surface adjacent the valve housing;
the valve core configured to rotate within the valve housing without appreciable gas transfer between the outer surface of the valve core and the valve housing;
the valve core having a first lateral end larger in diameter than the valve housing;
a sealing member pressed between the first lateral end of the valve core and the valve housing;
the valve core having a valve port surface which at least partially and selectively controls gas flow thorough the gas port;
a second lateral end of the valve core comprises a radially protruding component; and
wherein the protruding component of the bolt carrier contacts a friction surface of the bolt carrier to bias the sealing member against the valve housing.
2. The assembly as recited in claim 1 wherein the outer surface of the valve core is in close sliding fit to the valve housing so as to rotate therein.
3. The assembly as recited in claim 2 wherein:
the friction surface provides additional rotational friction to rotation of the valve core within the valve housing.
4. The assembly as recited in claim 3 wherein:
the sealing member is configured to bias the valve core laterally; and
wherein the sealing member is configured to laterally bias the protruding component toward the friction surface.
5. The assembly as recited in claim 1 wherein:
the valve port surface is detented from the substantially cylindrical outer surface of the valve core; and
wherein the valve port surface is selectively aligned with the vertical gas port of the bolt carrier in an unsuppressed position such that the valve core does not substantially occlude the vertical gas port in the unsuppressed position.
6. The assembly as recited in claim 5 further comprising a valve depressed surface on the valve body radially opposed to the valve port surface relative to the substantially cylindrical outer surface of the valve core.
7. The assembly as recited in claim 5 wherein;
the protruding component provides additional rotational friction to rotation of the valve core within the valve housing when the valve port surface is selectively aligned with the vertical gas port of the bolt carrier in an unsuppressed position.
8. The assembly as recited in claim 1 further comprising:
a tool engagement surface on the valve core;
the tool engagement surface not circular; and
a tool having a surface to cooperate with the tool engagement surface so as to selectively provide rotational force to the valve core when the tool is rotated.
9. The assembly as recited in claim 1 wherein the sealing member is radially compressed between the valve core and the valve housing.
10. The assembly as recited in claim 1 wherein the sealing member comprises an O-ring.
11. The assembly as recited in claim 1 wherein the O-ring engages a circumferential groove 116 in the valve core.