When I say that it isn't perfect I refer to the fact that the entire pistol grip has been moved rearward by 3/4" so the intended relationship between your hand and the trigger is changed. Sometimes, under recoil, the plates can rotate a little, leaving the pistol grip at a 2 or 3 degree cant in the direction of your strong hand. (They are aluminum alloy. I've thought about drilling, tapping, and locking them together with screws, but just haven't gotten around to doing it.) The slot on the bottom of the pistol grip (intended to lock on the rear of the triggerguard) now rubs - annoyingly - against your 3rd digit. It could use a filler block of wood or rubber. No big deal. If I could buy a longer Speedfeed pistol grip, I would.
The OAL measurement depends greatly upon how you choose to measure it - on what axis, and from what points. I have no way of knowing for certain how a particular police officer or conservation officer will choose to do the measurement in the field, so, while the added length provided by two sling plates may be long enough for the 660mm, I choose to use only three plates. And, no matter how I measure it, it measures up; with the 14" bbl, the three MI sling plates (available from Brownells), and the Speedfeed pistol grip stock it is definitely over 660mm in overall length.
This is a link to the sling plate. I used MI. Midwest Industries is registered with State, so Brownells can ship. (My GGG plate is virtually the same size. I don't know for sure about the Canadian-made versions, but I think they are virtually the same.)
http://www.brownells.com/aspx/NS/sto...LING%20ADAPTER
You would also need a replacement (longer) stock bolt. You can get this at any good industrial hardware store.
Now, I don't know you and I don't know whether you deal with Brownells. But, suppose I am full of s**t...and you buy the plates only to find that it is either too short, or too uncomfortable, or you just don't like it. Brownells has a "satisfaction guaranteed forever" guarantee. Anytime you want, you can return a Brownells product for refund, or exchange, or credit - as you wish.
You've got nothing to lose.