Well, unfortunately you’re dealing with magically animated creatures and that’s always a pain… mostly because they’re largely insensitive to it. That makes the most effective weapons against anything normally alive rather useless. Personally, I think that’s pretty well cheating. However, if they played fair they wouldn’t be villains, so I always recommend keeping a wide assortment of destructive implements at hand when trying to save the world.
Up first for consideration is the Elephant Gun. Usually a sizable caliber, these rifles are built to stop a charging Elephant or Rhino in its tracks, and guaranteed to shatter wood when it hits. Alternative, a .50 Browning machine gun offers similar firepower in an automatic package, provided you can cart around the ammunition and actually carry the sucker. Want to make an impression? Say it with sabots!
Supposing you prefer more close-range option, go with the shotgun. Oh, not them prissy little things people use on deer, no. I’m talking about a low-gauge shotgun, something along the lines of a punt gun, perhaps using multiple-barrels. I guarantee nothing this side of earthly will survive a hit from that, but you’re gonna need to brace yourself very well to fire it, unless you enjoy having your shoulder removed without anesthetic. Failing that, an automatic shotgun can fire several slugs (go with slugs, not shells) and clear out a room quickly.
Now we get into the really fun toys: light explosives! Grenades and grenade launchers are the way to really sell yourself as a badass monster-killing machine. Now, your average frag grenade might not be enough to do the job, so here we might want to follow in the Hollywood example and use a high-explosive device instead. Frag is best for soft targets, but there are pretty tough, so HE will throw them around and break limbs* like kindling**. This might not stop them entirely, but follow up with a White Phosphorous and enjoy the barbecue. They’ll be too broke to escape and you can optionally use any cedar-based monsters to grill steaks in the aftermath.
Now, while it’s true these are all handy options, now and then you may be getting into closer range, which is why I recommend keeping a more normal shotgun, sawed-off, ready at hand to blast off any nearby limbs. Sure- it’s magically-animate oak. Tough stuff. But knees and other joints are the loveliest things to rend! And even the worst terminator-wannabe is usually a lot less intimidating once it’s reduced to sprawling on the ground and hoping you come within nomming range.
*Pun intended!
**Ditto!