The problem with 302 redirects are that they are temporary, which often results in both pages being indexed in Google - The page you are redirecting from and the page you are redirecting to. If both pages are indexed in Google then that is problem as you have a duplicate page indexed.

As mentioned here: Google's page on HTTP status codes 


  302 (Moved temporarily). This code is similar to a 301 in that for a GET or HEAD request, it
  automatically forwards the requestor to a different location, but you
  shouldn't use it to tell the Googlebot that a page or site has moved
  because Googlebot will continue to crawl and index the original
  location.


So although you mention all your internal linking will use https, but external links inevitably will be with http, so Google is going to find some http links and 302 redirects, which could result in duplicate pages being indexed.

Here is video from Matt Cutts where he attempts to answer the question weather there are problems ranking sites that use https. Although he doesn't mention your question specifically, he does touch on the point that if doing this correctly, you should be using 301 redirects.

Can switching to HTTPS harm ranking? 

So to summarise you should not be using 302 redirects to force http, you should be using 301 redirects.

Is there any significant ranking penalty for using 302 redirects to force HTTPS?
Consider a Photon from Sun and travels with a velocity $c$. Now think we are that photon. For us, it looks like Sun is moving away from us with a velocity $c$. So, why don't we get attracted back towards Sun, because the mass of Sun would be infinite for us since it moves away from us with a velocity $c$.
