Sako Quad – Hunter Pro Synthetic inc Barrel – Multi-Calibre rimfire rifle for the rifleman who likes the flexibility of multiple rimfire calibres. The barrel change only takes a few seconds: Just insert a tool, turn it three full circles, and tilt the barrel upwards while pulling out the action. Then simply insert another barrel, and possibly change caliber. This makes the Sako Quad extremely versatile – and its accuracy is phenomenal. Corresponding barrels have individual serial numbers. However, the Sako Quad is no ordinary rimfire: It is a small bore hunting and training firearm that functions as its own system, complete with several options to choose between.