Definitive Impulse information!

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So, the Savage 110 bolt action rifle, has a bolt that locks into the receiver. And the long shank or short shank barrel threads into the receiver.

The Savage Impulse has a bolt with a changeable hexlock bolt head that locks into the Barrel extension, and the 110 style long shank or short shank barrels thread into a long shank or short shank Barrel Extension. The Barrel Extension is pinned and bolted into the receiver.