I was trying to drill a hole for bolts for a TV mount, using a 7/32 bit. About 1" in, the drill wouldn't go any further. It as was in the middle of where my stud finder indicated a stud (but it was about 2", so not sure if it was a real stud). But I tried to screw in the bolt with a wrench and it actually went in all the way (about 2.25" ). What do you think it was that the drill got stuck at, but I was able to wrench the bolt in? Do you think it's safe to leave the TV mounted with this bolt, or I should find a different spot?