Not quite refined. - Carlson's Choke Tubes Remington 870/100/11-87 Magazine Extension 10 Shot

Where the threads meet the barrel, there is a lip there follower gets stuck on. I had to file all sorts of things. Of course I knew I had to file the dimples on the 870, but I also had to file the inside of the extension where the pipe meets the threads. Will probably have to file it some more to make it work. Also this only holds 9 rounds and it's advertised as 10. The siding was trimmed as well, but it's still not quite right. I will have to refund it until it's smooth, but before I did anything aside from bumps on 870, it only fed reliably 2 out of 8 times. Had to unscrew the extension to get it to release the what I believe is the follower getting stuck on the lip inside the tube. I would really like a refund as it cost $66 and it doesn't work as described. Even with a lot of work, I'm still considering another option.