Since almost nobody knows what Merlins are I decided to make a thread explaining them. I hope this clears everything up about them (and it gets stickied so I don't have to keep explaining them).
#1 These were made with AKA quality. If you've ever used a Viking or Excalibur or even one of their regulators, then you know what I'm talking about. These are made with extremely tight tolerances, which most companies just don't do anymore.
#2 They have a Larger air chamber than any other cocker save it be the Rudy Cocker (because it has a giant LPC). This means they use an 11/16" valve for those of you getting an mQ2. This also means that their banjo bolt is larger (3/4"-20). They come stock with the same Tornado Valve that is on an AKA Viking/Excalibur giving them crazy consistency and flow. Here's a pic thanks to DeathOfAllThings to show you how much bigger the chamber really is.
#3 There are a few different kinds. Please correct me If I'm wrong. I believe that the old VLM bodies were used by Splat Attack for the First Revenges. These had a larger air chamber than stock cockers and a wire detent. The other kind is the VLM Merlin or just called the Merlin that were sold as body kits and used for the Revenge V2. These have the huge air chamber and either wire or Spyder style detents. They all had AKA threaded feednecks (.910"-20), cocker barrel threads (15/16"-20) and used old style or AKA style IVGs i.e. if you have an mQ Valve then you'll need to tap it with a 3/4"-16 tap to use a new IVG. They came in several different style of milling, some were near bricks like this...
and some were a bit lighter like this...
They also sold, and still sell body kits. They can come full sized, mini, standard or P-blocked.
#4 A Merlin can be milled in tons of different ways. Here are some examples such as a JMJ Featherlite thanks to Yakitori, a DC Merlin, a Half-blocked Featherlite thanks to PopeNewb, and DeathOfAllThing's own custom milling.