Sorry, yes your right, my brain said staggered, but i typed center, Your correct it's a stagger feed.

I did find this
"The original 110 was a "one size fits all " action typically referred to as the "J" action. They had a action screw spacing of 4.522"

Starting around 1988 the 110 screw spacing became 5.062" and starting around 1998 the short action with a 4.275" spacing.

Now....
There were some long actions ( 5.062") configured as short actions. The magazine opening was cut to accept a short action box with an extended front baffle to shorten the bolt throw ( bolt stop). "

It would appear to be the short action cartridge on a long action as noted, the screw spacing looks right @ 5.062 , my calipers dont open that wide, but a quick check with a tape puts it just over 5".

I "assume" that any 110 stock with 5.062 spacing would fit ? I am thinking i might find a beater stock to hack down to size, or a youth stock for it.

The barrel is stamped with both 110 and 22-250.

So i guess the other real mystery is what the little spur on the bottom right side of the bolt carrier/baffles is (i only have a round rear receiver to compare to so i don't know if this is a normal guide mechanism for flat receivers).