Hellsing Cosplay prop problem

I am working on a Hellsing prop for my Rip van Winkle costume for NDK, this will be the gun, i have found a colorguard rifle that can be used as a model for my gun. So I figured what the hell, might as well ask how to extend it a little.

http://www.algyteam.com/merchant.mv?Screen=PROD&Product_Code=EQ4103&Category_Code=EQUI_RIFL&Store_Code=algyteam&Offset=&Product_Offset=3

This is the gun I am looking at.

Could you post an image (for those of us that haven't watched the anime) of the gun you're after doing? Just so we can be a little more helpful.

Oh, OK



This is one view of her gun



Here is the other.