mossberg 500 issue.

[Shawrank]

hello sorry not sure where to post this. Im a newbie to the scene and am having a problem with my mossberg 500. seems the slide ring doesnt seem to thread on. it comes loose after a couple shots. what needs to be changed or replaced here? i read somewhere that there are 2 different sizes of slide ring im wondering if this is the right one. thank you in advance

 

[RePete]

Make sure the fore-end is on all the way.

When installing the lock ring, you need to push hard (without cross threading the ring) while turning. A correct tool helps here.