Just noticed that my colt m4 upper has about .25" play left right, meaning the handguards actually move they are not perfectly solid on there. Just wondering if this is common after a while, I just noticed it and it's been in storage, cant recall it ever having been that way before when shooting it. How do you tighten it? There is a ring towards the receiver that I tried rotating but it didnt seem to budge.

TIA

- rem

most of our issue weapons have the same movement with no noticeable degradation in performance (except they're a little loud).

ETA -> E5T