I saw this post and it hit home with me. I too recently purchased a Lancaster 3060 for the same reason as you did. I checked mine and luckily I did not experience the problems you had with yours...except i am disappointed in the furniture. Sorry, yours did not work out.
I likewise am interested in the Arsenal SGL20 and am seriously thinking of purchasing one on gunbroker. Did yours come to you as you expected. They look solid and everything I read about them is positive, but I also read the same as you about the Lancaster..................