A loader assembly for a paintball marker, comprising: a loader having a feed neck having a paintball path; and a feed collar connectable with the paintball marker, the feed neck includes a flange having a locking slot; wherein the feed collar further includes a lock having a pass-through port with a locking cross-bolt slidably residing therein and a locking seat shaped to receive the flange of the loader, when the lock is in an unlocked position; wherein the locking slot and the pass-through port are aligned when the loader is disposed in the feed collar, and the locking slot is arranged, relative to the feed collar, such that the locking cross-bolt can slide through both the locking slot and the pass-through port at the same time to lock the feed neck to the feed collar; wherein the pass-through port has a generally rectangular cross section and the locking cross-bolt is generally rectangular in shape; wherein the locking cross-bolt includes a recess through one face, the recess has a cross-sectional shape and dimension that is substantially the same as the cross-sectional shape and dimension of the locking seat such that when the recess is aligned with the locking seat, the flange is able to move vertically relative to the feed collar, and when the recess is not aligned with the locking seat, the body of the locking cross-bolt interferes with the locking slot to prevent vertical movement of the loader relative to the feed collar; and wherein the lock further includes at least one flexible locking detent which is configured to restrict movement of a locking cross-bolt through at least the pass-through port. a loader having a feed neck having a paintball path; and a feed collar connectable with the paintball marker, the feed neck includes a flange having a locking slot; wherein the feed collar further includes a lock having a pass-through port with a locking cross-bolt slidably residing therein and a locking seat shaped to receive the flange of the loader, when the lock is in an unlocked position; wherein the locking slot and the pass-through port are aligned when the loader is disposed in the feed collar, and the locking slot is arranged, relative to the feed collar, such that the locking cross-bolt can slide through both the locking slot and the pass-through port at the same time to lock the feed neck to the feed collar; wherein the pass-through port has a generally rectangular cross section and the locking cross-bolt is generally rectangular in shape; wherein the locking cross-bolt includes a recess through one face, the recess has a cross-sectional shape and dimension that is substantially the same as the cross-sectional shape and dimension of the locking seat such that when the recess is aligned with the locking seat, the flange is able to move vertically relative to the feed collar, and when the recess is not aligned with the locking seat, the body of the locking cross-bolt interferes with the locking slot to prevent vertical movement of the loader relative to the feed collar; and wherein the lock further includes at least one flexible locking detent which is configured to restrict movement of a locking cross-bolt through at least the pass-through port.