Can anyone help me?  I've finally decided to build a carbine length AR, lot's of experience with 20's (DCM).  I've got a couple of Wilson 1/9 16" bbls. I need to thread, chamber, and index the gas hole, but I cannot find a mil-spec or experienced recommendation for the gas port size,  anybody know what works best before I start drilling the wrong size hole in the new barrels, probably using just 55 to 69 grainers.  Thanks in advance.

Start with .063", test fire with 1 round in mag... see if the bolt-carrier locks back when fired... go from there till bolt locks open firmly.

That is interesting. I have a 20" HBAR that I cut back to 14.5" and reshaped the profile to take carbine handguards. The gas port in the barrel is .096"...

My question is what should a 14.5" barrel have for a gas port??? I was thinking it should be bigger than .096", but if a shorter barrel goes smaller, I'll have to plug and drill the front sight/gas block...