Got thousands of rounds of 5.56mm. Was contemplating 6.5 Grendel but the price of an upper would pale in comparison to the cost of stocking up on ammo. I have about 2K of Mk262, the majority of it being the IMI Razor stuff. Good stuff BTW.
I know 6.5 overshadows 5.56 in every category (well, maybe not cost), but if I was to choose a 5.56 round that would at least compete with the Grendel load would Mk262 be it? I plan on buying more of the Razor stuff if I stay the 5.56 course but was feeling out whether it was the closest you can come in this caliber to 6.5 Grendel performance across the spectrum: distance shooting, terminal ballistics, etc. I have a 20" build that would no doubt assist in lifting the Mk262 to Grendel levels, as well as a number of 14.5-16" weapons too.
Not shooting competitively, just a round that will remotely compete. I guess a “long” (length-to-diameter) bullet that has a good ballistic coefficient and therefore reaches out to the upper end of “mid-range” as well as good terminal effects once it gets there.
That’s a pretty damn good ballistic coefficient! However, for the price of upgrading all my “rainy day” ammo to the tipped SMK I might as well switch to the Grendel load!
Closest you’ll get to Grendel in a mag-length 5.56 is Black Hills 77gr TMK.
Ammo for Grendel, however, isn’t all THAT expensive… PSA recently blew out Prvi 120gr loads (which are sub-MOA for a lot of shooters) at $10/20 rounds; AIM has this stuff regularly at under $14/20. Hornady’s 123gr SST is usually under $20/20 rounds. And you can blaze away with Wolf 100gr steel cased stuff for about $7.50/20 rounds.
I recall from other threads your preference for the GMX load. How does it do with copper fouling? I have a couple hundred SSA 5.56mm NATO 70gr TSX and have heard about excessive copper fouling in as little as 50rds. I think this round (maybe the 70gr GMX?) could be the uber-556 fodder but the fouling issue is one that gives me pause.
Well, the GMX is gilding metal, not pure copper like the TSX (Gilding Metal Expanding). So, fouling, both in my experience and according to Hornady, hasn’t been an issue. No different from XM193, frankly.
Just go with a good, quality round in 5.56x45 and you’ll be fine. M193 and M855 are OK, but as a civvie you can load whatever you want. I’d suggest the RA556B, MK318, TSX 50, 55, 62, or 70gr, anything of Dr. Roberts’ “Best Choices” list; I have some Hornady 62gr TAP BARRIER, which is junk, so avoid that. (Look up its ballistics/gel tests at HornadyLE.com)
If you look at the energy and trajectory of 5.56 vs 6.5 grendel, there’s not a HUGE difference really, for the quality loads.
My buddies SPR build loves the IMI 77 great stuff. On a calm day he was making consistent head shots on steel silhouettes at 700 yards. Body shots at that range was close to 100 percent hits. If that load shoots anywhere as good in your gun as his you will have a very effective precision rifle for mid range targets.