Well, if I would be at your place I would have select “AK-47” as the best option and this would be the justification for me.
Google Considers ‘-’ dash as a space so in Google eye ‘AK-47’ and ‘AK 47’ will be considered as same. Now I have two options ‘AK-47’ and ‘AK47’.
Ultimate target is to get better visibility in Google (mostly it is) and to rank well it’s a combination of On-page and Off-Page optimization. I believe with a page ‘AK-47’ and some variation of AK-47 and AK47 in link building activity will more likely help me rank well for both the terms.
Even if you see the results in Google for these two terms you will not find much difference (at least on the 1<sup>st</sup> page)
