Originally Posted by 5.56X45mm
Because compact pistols have smaller surface area for gripping the firearm and also a smaller ammunition capacity. That plays a major part in the role of the weapon and it's accuracy. Barrel length is also a major issue in accuracy.
While I agree with you on smaller ammunition capacity, a shorter barrel should not affect accuracy. While it might seem a shorter firearm is less accurate then its longer counterpart, the reason why a shorter firearm is less accurate is because of the shorter sight radius. One thing a shorter barrel does affect is reduce muzzle velocity.
These figures are for the South African versions of the Galil
Lm4 18 inch barrel 3200 fps
Lm5 13 inch barrel 3000 fps
Lm6 11 inch barrel 2700 fps.
I achieved these figures using the same batch of 55 grain 223/5.56 military issue ammunition over a Chrony chronograph.
I did test fire a Colt Officers model, I wasnt impressed. Good for carry, but the recoil was spiteful. Its not a firearm I'd want to practice with too often.