Short action Long action confusion??

[1953greg]

i have 3 savage 220 swifts.
two are long action (both flat tops),
one short action long magazine (round blue receiver, savage 12 stainless barrel)
one of the longs has a short magazine (mcgowen stainless barrel)
the other long has no magazine (solid bottom receiver, savage 112 stainless barrel, blue receiver).

to simplify:
#1 is model 12 stainless barrel round blue short receiver stainless savage fluted barrel
#2 is model 112 single shot blue flat receiver stainless savage fluted barrel no letter in serial #
#3 is model 112 short magazine blue flat receiver mcgowen barrel no letter in serial #

i bought all them used over the last 5-6 yr
i understand the round/flat receivers and the mcgowen barrel
but is everything else just mix/match of whatever??

im not confused bout the long/short actions but
does anyone have any insight as to the why of the different configurations? thanks 1953greg