Gentlemen, I have been trying to find a definitive answer as to why the AH forend has that distinctive groove which he and Fraser were so fond of. There seems to be many different answers but nothing concrete or from anybody who actually knows and isn't just guessing. I have the AH book from Donald Dallas but I could not seem to find anything about the forend in it. Of course I could have missed it.
Any answers would be appreciated.

Matt.