Ahhh, the 7.62x35....Better known as the .300 AAC Blackout or .300 Whisper. Great caliber. Effective killing with super-sonic loads out to +/- 400 meters. The round was originally designed to be shot suppressed and subsonic, but the supers seem to be performing very well, too.
My most recent AR build, that I am in the middle of, will be a 300 BLK.
Just do some google research on the round and ballistics and stuff. And do lots of it. I always do before I buy anything.