I havn' t had that problem with my q2 and I' m shooting 390 grain gold tips and my q2 is cranked down to a half round off the bottom, I don' t know what poundage that is but should be close to 70. Just thought of something, last year I cranked the limbs all the way down and it got loud and picked up some vibration. I backed off a 1/2 round and fixed the problem. Are you cranked all the way down?