Last i looked, they had two ratings...the high one from thier Raptor pellets (and in some cases, there was a sample of those contained in teh box) and a second rating for lead pellets.
But they aren't really lieing...if you were to fine 10 shots, proably one or two of those shots from a new out-of-the-box gun would go as fast as they calim.
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I did find a CO2 rifle that would actually shot the raptor pellets well enough to be useful...so far, none of the powerful spring airs have, although a couple of low powered ones didn't seem to mind them.