Let the boy try along this bayonet-blade
How cold steel is, and keen with hunger of blood;
Blue with all malice, like a madman's flash;
And thinly drawn with famishing for flesh.
Lend him to stroke these blind, blunt bullet-leads
Which long to nuzzle in the hearts of lads,
Or give him cartridges of fine zinc teeth,
Sharp with the sharpness of grief and death.
For his teeth seem for laughing round an apple.
There lurk no claws behind his fingers supple;
And God will grow no talons at his heels,
The repetition of ‘sharp’ and ‘sharpness’, a typical Owen technique, emphasises the imagery of ‘grief and death’. The use for emphasis of different forms of the same word root is known as  polyptoton . 
 The sibilant ‘sh’s and hard 'p’s reinforce the idea of pain.