Vortex sport cantilever mount loose

[Kms33kms]

I’m messaging because my brother purchase a soringfield Saint AR AND HE ORDERED the vortex strike force (i think that’s name) and it come with the sport cantilever mount from vortex. It’s mounted on his rifle , but it seems to move very slightly forward and backward , just a tad , but no side to side wiggle or anything. Anybody know why? I did some google searches and all I could come up with was that it was because it was vortexes budget cantilever mount and probably
Just not top quality. Any help would be great thanks

 

[6.5SH]

That mount has a lug on the bottom. When mounting, slide it forward towards the muzzle to engage the lug. Use a dot of blue loc-tite on each screw and tighten the base screws to 20 inch pounds per the instructions.

If it is moving after that either the base or the upper rail is out of spec.