Gunsmithing 6.5 Creedmoor gas port hole size?

[Texar2]

Hey guys sorry if this has been addressed but I can not find it. I am building a 6.5 Creedmoor upper for my dpms type 308. Just finished up drilling the pilot hole but not sure what size to initially ream to. Thank you.

 

[ss355]

On my 24" factory DPMS tube, the port will take a number 43 drill bit (.087") with a little slop but won't accept a number 42 (.092"). So, my guess is that my port is about .089"-.090". I'd say mine is a little over gassed as it's somewhat rough on brass.