Frank de Haas in his book "Bolt Action Rifles" states on page 174: FN actions were made at first with the full inside collar, just as in the M98 military action, with the collar slotted on the right side for the extractor. At some point FN began to fudge and, thereafter, slotted the collar on the left as well, leaving only partial collars top and bottom.
I have never seen one as the FN action on my Husqvarna is slotted on both sides. (I don't remember looking for it on a FN action in a Sears Model 50 I once owned.)
Hope that helps.
"It is wise, though, to remember above all else: rifle, caliber, scope, and even bullets notwithstanding, the most important feature of successful big game hunting is to put that bullet in the correct place, the first time!" John Jobson
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