This may not be of tremendous help, I don't have a 16" but have built both 18" and 24" Faxon barrelled 6.5 Aero M5 weapons.
They both use "Heavy Fluted Match" barrels and I'm having feeding problems with both of them. The rounds get picked-up from the mag OK (JP BCG's) but get lodged between the mag feed lips and the feed ramps of the barrels. It requires some amount of force to drop the mag, and typically results in denting/scraping of the cartridge.
I've tried different mag's, BCG's, ammo, etc. and I'm still getting jamming.
I'm gonna try polishing the barrel feed ramps and hope that starts showing some improvement.
It appears to my under-educated eye that there is too sharp of an angle to the ramp. I don't know if that may be an issue with barrel/upper receiver incompatibility, or ?!?!
I have an 18" .308 build with the same components, it has never posed any feeding problems (or any problems, for that matter)
All (3) of my Faxon barrelled builds have exhibited great accuracy.
What kind of issues have you experienced?
I'll report back post-polishing.