Did a (very) quick check and seems the problem is elsewhere. Usually when the game closes up it's about graphics, but there shouldn't be anything wrong with my assets.
Maybe, but check the sprites you're using.
bigSprite, floorSprite, handSprite.
I'm having problems with the secondary weapon for HWP as well, so test your HWP with unlimited ammo first.
For me, if I put a weapon with infinite ammo as primary and secondary then everything works.
But if I put a weapon with finite ammo as secondary, the ammo is never loaded.
And if I put it as primary, the weapon is reloaded but the stock in store never goes down.