Free The Corridors of Time by Poul Anderson

painted with the fylfot, and had for weapons a flint dagger and a beautifully fashioned stone ax.
     His lips were drawn wide in carnivore anticipation.
    The chariot he followed, evidently his chieftain’s, was a light two-wheeled affair of wood and wicker, pulled by four shaggy
     little horses. A young boy, unarmed and clad merely in a loincloth, guided them. Behind him stood the master: bigger than
     most, wielding an ax so long and heavy it was a halberd, with two spears racked ready to hand. The chief had a helmet, corselet,
     and greaves of reinforced leather; a short bronzesword hung at his waist, a faded cloak of linen from the South fluttered off his shoulders, and a necklace of massy gold flashed
     beneath his shaggy chin.
    Such were the Yuthoaz. When they saw the uneven line of fishermen, they slowed their pace. Then the lead charioteer winded
     a bison horn, the troop howled wolfish war cries, and the horses thudded into gallop. After them banged the wagons, leaped
     the yelping footmen, boomed the axes on drum-head shields.
    Echegon’s gaze pleaded with Storm and Lockridge. ‘Now?’ he asked.
    ‘A little longer. Let them get close.’ Storm shaded her eyes and peered. ‘Something about him in the rear – the others block
     my view —’
    Lockridge could sense the tension at his back: sighs and mutters, feet that shifted, the acrid stink of sweat. Those were
     not cowards who waited to guard their homes. But the enemy was equipped and trained for war; and even to him, who had known
     tanks, the charge of the chariots grew terrifying as they swelled before his eyes.
    He brought up his rifle. The stock was cool and hard along his cheek. Storm had grudgingly agreed to let the twentieth-century
     guns be used today. And perhaps the fact they were about to witness lightnings, even on their own behalf, stretched thin the
     courage of the Tenil Orugaray.
    ‘Better let me start shootin’,’ he said in English.
    ‘Not yet!’ Storm spoke so sharply, above the racket, that he gave her a glance. The feline eyes were narrowed, the teeth revealed,
     and a hand rested on the energy pistol she had said she would not employ. ‘I have to see that one man first.’
    The charioteer in the van lifted his ax and swept it down again. Archers and slingers at the rear of the Yuthoaz halted, their
     weapons leaped clear, stones and flintheaded arrows whistled toward the seafolk.
    ‘Shoot!’ Echegon bellowed. He need not have done so. A snarl of defiance and a ragged volley lifted from his line.
    At this range, no harm was done. Lockridge saw a missile ortwo thunk against a shield. But the Yuthoaz were in full career. They’d be on him in another minute. He could make out the
     flared nostrils and white-rimmed eyes of the nearest horses, blowing manes, flickering whips, a beardless driver and the savage
     grin that split the beard behind, an ax upraised whose stone gleamed like metal. ‘To hell with this!’ he cried. ‘I want ’em
     to know what hit ’em!’
    He got that chieftain in his sights and squeezed the trigger. The gun kicked back with a solidity that strengthened his soul.
     Its bang was lost in yells, hoofbeats, squeal of axles and rattle of wheels. But the target flung his arms wide and fell to
     earth. The halberd soared through an arc. The grass hid man and weapon alike.
    The boy reined in, drop-jawed and scared. Lockridge realized at once that he needn’t kill humans, swung around and went for
     the next team of horses.
Crack! Crack!
One animal per bunch would do, to put a wagon out of commission. A stone glanced off the gun barrel, which rang. But the
     second chariot went over, harness tangled, tongue snapped across, left wheel demolished in the wreck. The live horses reared
     and neighed their fear.
    Lockridge saw the charge waver. Two or three more of those battle cars stopped, and the invaders would bolt. He stepped forward
     to be in plain sight, his blood too much athrum for him to care about