Hi this is my first post on this here forum and I hope I am putting this in the right place.

Now the issue at hand is that I'm putting together my AR-15 (Spikes Tactical .22lr), I'm starting off with a .22lr and I plan to progress to a .223 upper later so I can have two guns in one. But I've got some issues now, I haven't gotten the gun yet but I've already ordered a stock separately, it's complicated, you can't export guns with telescopic stocks from the US anymore so I bought one separately and now have it at home, it's a mil-spec MagPul CTR stock with an extra .55" buttpad. I also got an extra long vortex flash hider I will put on. All in the name of increasing OAL. In a regular 5.56 AR this would not be a problem as the barrel does not recess as far as it does on the ST model, it'll look like a 14.5" which is nice but problematic nonetheless

Thats the problem I got you see, the OAL requirement in Finland is 840mm or 33.1 inches, it's measured with the stock fully collapsed. So I already got the stock and I already got the flash hider, but from what I see I am off 0.6 inches from being within the OAL even though I got the extra long buttpad and flash hider. So what can I do?

My first idea was to get a sling mount, an extra thick one like the one from Midwest Industries maybe could work?
http://www.midwestindustriesinc.com/...category_id=97

Googling for answers I just found this which looks interesting:
http://lgweaponry.com/ad_sheets/carext.htm

It's designed it seems to do exactly what I need, add some length and allow me to keep my carbine stock. But I've never heard of this company before, and I am not sure the solution is sound. So I am turning to this place for some answers.