HVAC Hawks suggestion was right on.
if your using a hammer drill, your getting blow out on the inside, reducing mounting thickness.
Before we get into any howling matches let me say that in hollow cinder blocks you need something that just can't pull out without really busting up the cinder block. That's where a good size toggle bolt with wings comes in. I've tried really hard using pry bars to force them out of cinder blocks and end up busting the cinder blocks to bits. For shelving as Jim said you can't risk it falling down on your head. Please get and use the largest toggle bolts you can use for this job. Also, if you can stand it, drill all the way through the cinder blocks and use threaded rods. Put a steel plate on the back side of the cinder block with holes in it for the threaded rods. Now let's see that come out. The whole wall would have to bust apart. I would need to show pictures of what I have in mind using plates and threaded rods. The idea is to prevent any pulling out what-so-ever. I really think the toggle bolts are the best bet in the hollow parts of cinder blocks. They are all steel and hold well.
I wish I had pictures showing the toggle bolt close up, measuring for hole size, inserting it through the hole and then tightening. There is one nasty bitchy part with a toggle bolt. If you take the screw out of the butterfly, it falls down inside the wall. Then you have to use a new toggle bolt.
Hint: Practice use of toggle bolts by drilling a hole or two in a scrap piece of 1 x 4 or plywood. Insert it and tighten it up. This way you can see what's going on.
Not to change the subject, but what happened to JimDon. His posts are gone!
WOW They are gone!!! I sure hope he didn't get into a fight with Team Orange about something and they deleted all of him on this forum. Maybe it's some insane glitch and later they will be back. Jim seemed like a fine member of the forum to me.
UPDATE: I do see some other posts of his on the forum. My guess is he didn't want there to be any *&^%$ on this thread. I think he will be back before long. Only time will tell for sure. If anyone needs to have posts removed it would be me the old howling hound of the forum and not him.