I am considering a new build. I want to do an AR platform 6.5 creedmore. Having never done an ar 10 base I have heard a lot about how some brands of components don't work well with other brands. Can anyone give any real world insight on what will or won't work together, or problems they have encountered?

Anybody?

Usually best to stick with one company for the action of the gun. You can play with furniture, triggers, etc....

aero precision has everything as does JP.

Try posting your question in the correct forum, OP.  And read the stickies before you post.

I'm not an expert but here's the short version:

The build it yourself market is dominated by DPMS pattern components. These will be labeled as LR-308, AR-308, or DPMS pattern. The DPMS pattern accepts Magpul PMAGs. Aero Precision components are DPMS pattern.

The AR-10 pattern is different than DPMS and not typically built by sourcing components. The AR-10 does not accept PMAGs.

The uppers and lowers are not interchangeable between DPMS and AR-10.

And this is where things start to run off the rails.  AR-10As take PMAGS; AR-10Bs do not.  By modifying an AR-10B upper, someone apparently got one to work on a DPMS lower - that is, a Gen 1 DMPS lower.  DPMS Gen 2 is an intermediate length.