That movement is the amount the bolt body rotates until the cocking piece pin is picked up by the cocking ramp to begin compressing the firing pin spring and moving the firing pin rearward.
Its not there when the cocking piece pin is in retention at the top of the ramp when the bolt is in it's cocked position or it's control has been transferred to the sear-trigger when locking the the bolt to battery.
BTW, a bolt lift kit will do nothing to correct it .
Bill
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