Over the years, I’ve accumulated kind of an eclectic mix of surplus and commercial 5.56 ammo. When Spotsman’s Guide had all that SA in 300 round battlepacks, I bought a few tubs and I still have a decent amount of it. A year or so after that, I got about 3k of the Spanish M855 a, nd some time after that I also picked up 1200 rounds of Israeli M855. The IMI stuff was new production at the time (99 headstamp I think) and it’s always been stored right. The SA and Spanish stuff has been stored right since I got it, but prior to that it’s anyone’s guess. Over the last year or so I’ve also gotten some BH 69g SMK blue box, Federal M193, and Privi 75g match, and Winchester Q3131A. Like I said, my ammo bin for 5.56mm is a bit diverse.
I’ve often wondered what effects father time might have on the ammo, and how consistant one “standard” loading from different sources might be so last Friday when I went out to run some handloads through another rifle, I packed up my mix of 5.56 to run through a chronograph to see what kind of numbers I’d get. Weapon used was my M16A4gery (BCM 1/7 upper, Knights rail, TA31 ACOG, with RRA match trigger added) shooting from the bench at 100 yards. 20 rounds of each different ammo was fired in two strings of 10. Below are the results.
Spanish M855 (circa 1992)
3057fps average
SD 14.4 ES 44
3.33" group
IMI M855 (circa 1999)
3034fps average
SD 18.9 ES 50
3.67" group
SA Surplus (early 80s?)
3172fps average
SD 13.6 ES 40
3.87" group
Win Q3131A (circa 2002)
3120fps average
SD 17.6 ES 64
2.53" group
Fed M193 (circa 2009)
3187fps average
SD 24.4 ES 85
3.26" group
Privi 75g match (circa 2009)
2711fps average
SD 22.0 ES 63
1.83" group
BH 69g SMK Blue (2010)
2700fps average
SD 28.1 ES 89
1.73" group
I was a bit surprised at how well the older SA performed compared to some of the newer Federal M193. The Spanish M855 also surprised me against the IMI M855 that I quite frankly assumed would perform better. Maybe I need to search out some more of this Spanish stuff…
As far as the groups are concerned, I’m sure that the ammo shoots better than that, but that’s what it shot with me on Friday. I’ve had better days on the range, but it is what it is.
Saleen