Originally Posted by
jiffx2781
The safety selector on the MV/MH rifles is a proprietary part. A "standard" AR15 safety will not fit and function in this rifle. The one that comes with it has a portion that has been made to smaller dimensions to allow for clearance of the part of the upper receiver that the rear trunion pin inserts into. It also takes a different detent and spring which is held in place by a tiny set screw located under the pistol grip.
To keep a long story short, a standard AR15 safety will NOT simply drop in and function. There will be interference that will cause the upper receiver to bind on the safety selector when trying to reassemble. It won't fit back together and the safety won't function.