Madbull gemtech raptor ii suppressor

[tirabbi]

INFO NEEDED PLEASE

I have an MP5 a4 with the surefire foregrip. I need the dimensions of the raptor so that i can tell if it will fit with my fore grip. I notice that the connection end looks to be a smaller diameter than the general length of the suppressor?
If any one has this piece of kit could you tell me what the smaller diameter is & how far up its length does the small diameter go.
I want to make sure it is clear of the torch head.

Thanks in advance.