http://www.reflexsuppressors.co.uk/
It does change the balance of the pistol a fair bit but as I only really the gun rested (on a beanbag) it doesn't bother me. I use my 1377 as a silent back garden plinker which it's very well suited to - over 15 to 20 yards the groups are very, very tight. I'm not very accurate with it unsupported so I've never tried to shoot a live target....I use my shotgun for that!
You do have to use a bit of thread sealer to fit the adapter but it works very well...not sure how easy it would be to remove though.
IMO the key to getting accuracy with these guns is getting the trigger sorted – without that they’re…well….crap