The flash Hyder is 3 1/2 inches long, The barrel inserts into that first vent hole ,which is 1 3/4 inches.ironeagle ships Su16 mods made by Red Lion precision. Can't get a trigger or stock though ( they are not allowed to ship those two items). Because the barrel is permanently attached to receiver my gunsmith couldn't fit it in his lathe so we went this way. I don't see any flash, so I can't answer that question. It covers the raised ring on barrel and it only adds about 1 1/2 overall length to barrel. I've fired 100 rnds fairl fast and got the barrel really hot and the flash hider didn't budge. I like it this way but it's not for everyone, I'm sure it would have to be done perfect for it to work.
