Tuning Bottle moves on MKII

I mounted a Saber Tactical bottle clamp to my FX MKII to use for both a sling attachment and/or a bipod. Yesterday I shifted the weight on my gun when using the bipod and the bottle rotated a little bit. This is the first time that I've experienced the bottle having 'play'. Is this normal? I didn't see a set screw anywhere that can be tightened. I'm sure it's an easy answer and hoping someone out there knows what's up.

Kevin
 
I noticed the same on mine. I don't know if the valve on the gun may be bottoming out before the bottle makes a really tight matting or if the surface area on the gun side isn't large enough. I'm leaning more to the idea of the valve bottoming. To eliminate the chance of either happening I just machined a Delrin washer that made the bottle tighten sooner plus give the gun side more surface area. 

Jking

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