re: how many of you have been delayed for a background check?

It's up to the FFL really. He is required to 1.) wait until the NICS calls him and says it is OK to transfer the firearm(s) or 2.) wait 3 regular calendar days without hearing back from NICS.

If three days has passed and he has not heard back from the NICS he is clear to transfer the firearm. Now, say he transfers the firearm on day 3 then on day 10 the NICS calls and says don't do it. He just gives them your info and ATF goes and gets the gun from you.

Having said all of that, different FFLs have different policies. I bought from one once that had a 5 day delayed waiting period.