ProMag AR-15 9mm Magazine Quick Change Adapter Block

Wanted to give this one a try since the Hans mag blocks are so expensive and other options are not readily available but I ended up with a 90$ paperweight. Tried it with my CNA 7.5" 9mm upper and two different lowers (BCL/S&W) with the same result. I'd get constant jams : the spent casing wouldn't eject properly then get all jammed up with the bolt trying to chamber a fresh round. I'd get a jam every other round. Looks to me like an ejector problem as the ejector on this unit slides from left to right and can't be adjusted/secured properly. These two lowers work flawlessly with both my Spike's and AD9 mag blocks. Just save your money and get something else.