….chamber feed properly? AND, does single feeding, gently, help with accuracy?

Thanks!

Will it feed, sure, why wouldn't it. But a match (i.e. tight) chamber and fully chambering some ammo can be an issue. A "Match" chamber is a minimum spec chamber. In the world of gunsmithing, most chambers are SAAMI chambers, which are chambered on the max size chambering. Match chambers I've seen had a minimum spec head space and short throat. I've seen on multiple occasions where "match" chambers struggled to fully chamber multiple types of ammo because of the short throat or min spec chamber. Honestly, I've never understood why a match chamber would be used on a battle rifle like an AR-15. I've seen this cause issues in some 223/5.56 and 300 blk out ammo. My blk out ammo with new brass would fully insert into my chamber gauge no problem, but in some really tight "match" chamber AR-15's, it would chamber tight and need a tap on the forward assist to go all the way.

On the single feeding, I don't know how you "gently" feed the rifle. You can put the round manually into the chamber and release the locked bolt forward. But trying to gently ease the bolt closed on a semi auto would not be how I would recommend chambering it. I want the bolt to release from a locked position.