You could cut-and-refit his crossbow wrist so the butt end of the crossbow is on the ground and he's supporting it with one hand as he fends off an attacker?
I would say turn the sword into a crossbow bolt, but you'll need to rotate the hand around, say, 90 degrees clockwise to look more like he's going to reload his crossbow rather than using said bolt to hit his enemy over the head with (which wouldn't be the best way to use it even for a strong Uruk).
He already has made some of the pike warriors with those crossbows if I remember rightly, but you can't fault him for wanting to experiment with the other poses as well
Thanks all for the advise really helpfull. @Lord Agragax of Lunaxoatl correctly said I already converted two (broken) pike Uruk-hai to crossbow Uruk-hai. @JTSleep Exactly in the way that you proposed My thought for the new crossbow conversion is to use the warriors with shield, because there are too much of them in a box. I will give this one a try, thanks I will let you guys know how it turns out. Grrr, !mrahil