Volume overcomes a lot of deficiencies. I looked at the adapter a while back, when I had the opportunity to lay hands on one. Neat concept, hard to use your sights.
Edit to add - back when these things were news, a few people on the form 1 forums reported buying the correct sized adapters and form 1'd them. I imagine the engraving was a PITA. I also have no idea what you'd record for length...