Not really wanting to get involved in this personal "Discussion"
However re "Perch Belly". Notice the lines of the Stock ARGO44 posted & the lines of the 21 stock. The lower line of the stock on the Spanish gun is a continuation of the grip area just behind the trigger guard, ahead of the half pistol grip.
On the 21 the lower line of the stock drops lower & is about in line with the bottom of the rear trigger. That is the Perch belly, Perch you know do not have a straight line belly.
Beauty, as they say, is in the eye of the beholder, but personally, I like the bottom line of a shotgun stock to be in line from the back of the trigger guard to the toe of the butt plate, just far more ascetically pleasing in my eyes. Regardless of whether it is a straight grip, half or full pistol grip.
