I have a RRA AR-15 and want to update the hand guard to a ODIN WORKS O2 Lite. Im not sure if I go with the 15.5 or 12.5 inch on my 16 inch barrel. Could you guys post pics of your Ar15's with 16 inch barrels with with either a 12 or 15 inch hand guard? Thanks for the help! JImmy
Bottom gun is 16 inch 556 with a rail measured at 9.5.
Next up 223 wylde is a 16 inch gun with a 12 inch rail.
AR9 up top is a 15 inch rail.
If you run a bipod, getting it out closer to the muzzle will get you more stability and better groups. Running a light closer to the muzzle than my bottom gun will give you less of a shadow.
Longer hand guard will give you more sight radius and mounting space, but I fit BUIS, optic, light, sling mount and VFG on my shorty without too much of a problem.
Top AR’s hand guard stops right at muzzle device crush washer.
With quad rail system like on the bottom you have plenty more options without worrying about screws hitting the barrel or gas block. Top two are Mlok requiring planning the location of things so as to avoid the screws interfering with the barrel or gas block as they flex. So with Mlok I’d say longer is definitely better to give more options to mount everything without barrel or gas block interference. Longest you can comfortably reach.
On the middle gun with the 12 inch guard I had to give mounting position some real thought and experiment to get everything I wanted on it with no interference and also get my support hand where I wanted it. Had to search a bit to figure out a bipod mount system that took up the right amount of space to let me fit the mount in front of the hand stop towards the muzzle and also have my hand stop far enough forward for me.
If you’re not mounting much 12 or 15 may make no difference, but you could also end up wanting more stuff on there down the road. Having the space already would be nice. Like buying a little more house than you need now so if you need extra space in a couple years it’s already there.