Any explosion in space might produce very fast moving projectiles, that after getting slingshotted by planets may pick up way more speed.
Same might happen with every bullet that misses. They are likely to be fired with fraction of light speed, then they can gain more speed.
Some shrapnel might leave the solar system, but many will be trapped in orbits around planets, sun etc producing a perpetual hazard.
This means everything in space must be heavily armored, which increases the cost of spacecrafts, propulsion and transporting materials. There cannot be any light fast crafts, everything must be covered in couple inches of metal.
Is this is possibility?
Edit: Thanks for the cool discussion guys.