Note to readers. The AR-15 was the U.S. Military Weapon were the AK-47 was the Russian made weapon of choice around the world.
2. It is loud because it is made out of sheet metal. This could be defeated by easily adding sound dampening plates to the sides of the receiver and the dust cover.
3. The barrel is not long enough to really be considered an accurate rifle. Could be offered in a model with a longer barrel. The barrel is indeed cut and keyed into the receiver and there is an issue of head space from the bolt to the barrel.
4. The stock distance to chin makes it impractical for a long range rifle because it is not long enough from shoulder rest to where the trigger is held. There is a holding it out in front of you away from the bastion of your body effect.