jeff,
i didn't like everything i saw on his site; but i liked it enough to think of it as food for thought, too. some of it is appropriate for re-chamberings, etc.
fred M'
that poor rendition of an underlug -- made of soft steel -- and the cut-out of so much metal is why i coat those parts, and others, with the molybdenum disulfide-type lube from Valvoline (letting everything sit for two weeks) before i ever shoot the Handi's. the idea of the moly' etching its way into the metal seems to work from what i can see. my barrels/hinge pins have held up well so far but i hope i never have to eat those words. at the end of the season i pull the forearm and remove the camo' tape from the barrel and do a thorough cleaning of the barrels and a re-bluing. the initial use of the moly' grease seems to have protected the barrels very well from rust.
as far as interchangability goes, at the risk of sounding simplistic -- i don't use the accessory-barrel program. i lay down enough money to get a whole new rifle including the frame and stocks......because in the long run it is a bargain. to each his own, but i don't plan on ever ordering just a barrel from NEF. i'd rather wait for a rifle to go on sale. maybe i'm lucky -- actually calling it 'blessed' -- but i've not had a gap at the back of a barrel / breech, nor sideplay, etc.etc.etc. i've interchanged barrels a couple times without firing them and all seemed very well.
take care,
ss'