On history Channel. https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwiRkZfejqX7AhUHj2oFHUL_CtMQFnoECB8QAQ&url=https%3A%2F%2Fwww.history.com%2Fshows%2Fmountain-men-ultimate-marksman&usg=AOvVaw0qJuNmgMDXDuvtbSS8jb_Y
Pistols will be louder than rifles because of the length. Something sounds off with it being as loud as you say on the g44. Also I've never had much luck on the Aguila ammo.
The difference between billet and forged receivers is the bonding of the metals in forging. Forging allows tighter tolerances on the molecular level.
Here's a article that explains it much better than me...