Blammer,
Straight up M855 is kinda scarce right now on account of Terrorist season being open.
The most commonly available stuff is XM855PD that is sold loose in boxes of 1,000.
The stuff is NOT front line ammo, and is sold for training only for a number of reasons for each individual lot that is mixed together in the box.
Essentially it is rejected ammo that has been deemed "Safe" to fire.
Poor waterproofing, substandard velocity, or accuracy, etc. and then mixed in with the stuff are cartridges that were obviously issued in training, and not fired, but showing the markings from being in a M249 belt link.
The stuff should be gone through with a cartridge gauge and a jaundiced eye, as you will find cracked necks, and other obvious defects here and there.
When the obvious have been culled, it's not too shabby for practice.
The Wolf Polymer isn't as bad as it's made out to be.
Yeah it's underpowered, and accuracy kinds sucks when compared to good surplus or commercial ammo but it's cheap, safe, and for high volume-short range(50m or less) practice it makes sense.
I have seen little if any difference between the 62 gr loadings from Wolf, from a 1-7 or a 1-9 barrel.
I actually just run the 55grFMJ on account of it being a smidge cheaper.
XM193 ain't bad if you can find it.
It also is drying up.
Recently there has been some Brit Radway 62gr on the market.
The Brit SS109 is not the same as the US bullet, and the Brit loading is about 100fps. slower in my rifles.
Word is that the SA85 wont tolerate the battering from US spec ammo on a constant basis, so they load their ammo to accomodate the rifle.
Hope this helps!
E4E