RWA ptw hop up with Deepfire barrel

[MasterGouken]

I have a question regarding using these two items together.

As you can see in this picture the RWA hop uses an oring on the end of the barrel and then the adjuster goes on:

 

 

The deepfire barrel doesn't have space for this oring as the adjuster won't then sit flush with the end of the barrel as in the picture above.

 

This is a pic of the deepfire barrel, when the barrel key holes are aligned (they aren't in the picture) you can see there's no space for the oring, just the adjuster:

 

 

Is this going to cause problems?