Either way, I recommend ordering a box of which ever one you are looking for to see if it works for you. IMI makes some 5.56mm 77 Grain SMK OTM LR MOD-1 Razorcore IMI Ammo that is available in 20 rd. boxes.
Thanks. I had some SIG 77 gr OTM. Found out it’s SMK. My gun hates it. It’s SUB moa (barely with 5 shot group, easy with 3 shot). With Hornady 75 grain BTHP Match. The SIG 77gr SMK is 2”+ in my rifle. It shoots a 1.5” with Hornady 62 gr FMJ.
It’s a 556 chamber so maybe I’ll try it in. 556 load. Surprising to say it he least.