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 . <EOS>