I went shooting today and something weird started to happen when I used the sling for support while shooting from the standing position, my groups began to migrate left of where is was aiming about 2" at 25 yards. Also my usual dime sized groups at this range balloned out quarter sized groups with the same ammo I always use.  As I was doing my cleaning this evening I noticed that the delta ring was real loose and could be moved about pretty easily, then I noticed that I could wiggle the front sight base back and forth with little effort.  This is on a nearly new quality brand rifle so I was suprised to say the least.

Has anyone ever heard of this happening?  I will be sending mine back for warranty but what is the fix for this?  

Thanks

Sometimes the barrel is torqued down wrong because of a false reading caused by a burr in the threads.  After a little shooting the burr can get flattened and leave a loose barrel nut.  I saw it on an FN M16A2 once.

It's easy to solve.

A lot depends on what you've got.  Some of the part kit guns use pretty poor parts.