Here's a way to shorten and tidy nylon type straps, NATO and similar. Tools needed, wrench or vicegrips, sharp knife and a Zippo!
plus a couple of suitable coins.
Not sure if this will work well or not, an embedded video that is? In case the link doesn't work, take two suitable similar copper coins and measure where you want the new (shorter) end to come, place a coin top and bottom and clench up with the vicegrips or wrench tightly. Using a hobby knife, cut around the coins to get a nice curved end, then use the Zippo lighter to cremate the end and seal it to prevent fraying.