User blog comment:Xilinoc/Ch. 575 - THE KILLERS HIGH/@comment-14244059-20140403071431/@comment-14244059-20140403222949

Well, Gordon's gun appears to be some kind of unique Quincy Cross-based weapon, but Gremmy appeared to create multiple real world weapons to use against Kenpachi. However, because he is a Quincy, I imagine they'd be made out of reishi and fire either reishi or reiryoku projectiles. Then again, we don't really know how Gremmy's powers work compared to an ordinary Quincy's powers.

I'd still say it's fair to compare them to their real world counterparts in terms of effectiveness, assuming that they have no boosts in power.