I think I may have found the problem. You are only creating 1 animated sprite while the rest are just normal, unanimated sprites. So try this:
Rem ***** Main Source File *****
create animated sprite 200, "media\player\axe_001.png",8,1,200
`Max bullet life
MaxLife = 200
MaxNumOfBullets=300
Dim Bullets(MaxnumOfBullets,200)
`Number of milliseconds between each bullet
BulletWait = 400
handleweapon:
for b = 200 to MaxNumOfBullets
// if it doesn't exist then create the animated sprite
if sprite exist(b) = 0
create animated sprite b, "media\player\axe_001.png",8,1,200
endif
`Fire Sprite
if spacekey()=1 and Bullets(b,101)=0 and (timer()-LastCreated) > BulletWait
sprite b, sprite x(101),sprite y(101),200
scale sprite b,30
play sprite b,1,8,50
offset sprite b, sprite width(101) /2, sprite height(101) /2 +40
rotate sprite b, sprite angle(101)
Bullets(b,101)=1
Bullets(b,200)=0
show sprite b
move sprite b,6
LastCreated = timer()
endif
`If fired while moving
if Bullets(b,101)=1
play sprite b,1,8,50
move sprite b,6
l = bullets(b,200)
inc 1
Bullets(b,200)=l
endif
`Stop if at end of life and decrement bullets
if Bullets(b,200) > maxlife
Bullets(b,101)=0
hide sprite b
endif
next b
return
