Bolt-ons are performed by vehicle fans or those people who are identified as modders. There isn't any standard bolt-on because modders are various from one another. A whole bolt-on to at least one modder is simply a partial bolt-on to a different. That’s how varied this field of endeavor is. https://bookmarklayer.com/story18042363/top-guidelines-of-what-is-a-bolt-carrier-group