Frame size is between small/medium for a "Semi Auto". Size specifications are : Overall Length 6.7 in - Overall Height 4.7 in - Overall Width 1.1 inches. (Barrel Length is 3.6 inches).

It is the smallest frame for the P320's.

CALIBER
9mm Luger / 40 S&W
ACTION TYPE
Semi-Auto
FRAME SIZE
Sub-Compact
FRAME FINISH
Stainless Steel
FRAME MATERIAL
Stainless Steel
SLIDE FINISH
Nitron
SLIDE MATERIAL
Stainless Steel
ACCESSORY RAIL
M1913
TRIGGER
Striker
TRIGGER PULL DA
6.5 lb (29 N)
TRIGGER PULL SA
N/A
BARREL LENGTH
3.6 in (91 mm)
OVERALL LENGTH
6.7 in (170 mm)
OVERALL WIDTH
1.3 in (33 mm)
HEIGHT
4.7 in (119 mm)
WEIGHT
24.9 oz (706 g)

Hey Benny, you did not link/specify a firearm for us to attempt to answer. Thanks.