I have tried so many different drill bits, I have a good hammer drill but the bits always slide off the pebbles. I did have a drill bit once that worked but cannot remember the name of it, I think it was something like, destroyer, destructer, demolisher. Can anybody help please, I have loads of shelves to put up and I cannot get a good hole.
You have probably got 'no fines' concrete walls ie no sand as such in it.
Hilti do o 'no fines' drill bit or used to when I worked for them. An alternative would be a smaller bit than the size of the fixing- as the hole ends up bigger everytime.