It's legit as a far as I have come across... It uses shaver blocks, if you read the codex entry there. The original
codex entry for Mass Effect states:
"In Mass Effect, to generate ammunition a weapon shaves a projectile the size of a sand grain from a dense block of metal contained within the weapon's body."
Mass Effect 2 expands on this for the
Eviscerator shotgun, going as far as to say this:
"Where most modern firearms shave off chips or pellets from an ammunition block, the M-22 shaves off serrated metal wedges designed to fly aerodynamically."
That seems to be heavy-gauge shotgun pellets under a different name.
As such, what they're saying about the Talon is that it carries six of these ammunition blocks (probably smaller than the original shotgun blocks - possibly one block split down into six) in order to reduce the amount of heat generated when the pellets are shaved off it.
After all, it's in ME1 codex as well that omni-gel (and later ME2's omni-tool codices) that there are field manufacturing kits for ammunition for things like the Cain and so forth - It seems the thermal clip is not the thing that is reloaded, but the blocks of ammunition themselves.