Modifications needed. - Monstrum Mossberg 20-Gauge Shell Carrier with Picatinny Rail Mount

Appears to be a quality product but I had to do some modifications to it in order for it to fit my Mossberg Maverick 88 20 gauge shotgun. The pump action would not fully engage or work properly so I had to trim down/out the left side of my synthetic forearm/pump. I also had to cut off one of the shell holders on the end in order for it to fit and function properly. I ended up cutting another one off of the other end as well because it looked stupid and wasn’t aesthetically pleasing to the eye. Now it holds 5 shells instead of 7, but I think looks better anyway.