HellBoy M4I have had my HellBoy M4 since they were first available in North America, and I also bought a spare magazine.
I added rails to the hand guard for a light and a vertical foregrip. I wish the pistol grip was AR compatible.
While I had the gun field stripped, somehow the charging handle came out and the spring was stretched so much that it doesn't work properly. It isn't that important, since it just simulated the charging handle action, and doesn't actually do anything for the gun to function.
Even still, I would like everything to work properly.
I have found the two magazines I have shoot at different power levels.
The one that came with the gun was tested and averaged around 500 fps, but the spare magazine averaged much lower, around 425 fps.
The fire selector switch has become very loose, and unless I can figure out how to tighten it up, I expect that it will fall off the gun eventually.
Despite the couple of criticisms, I still enjoy handling and shooting this M4 replica.