High Velocity Rounds + Splinter Support Gem

If you place the Splinter support gem into High Velocity Rounds, it doesn't seem to break armor at all. I don't see any text on High Velocity Rounds that says the skill cannot be made to break armor, and the gem allows itself to be engraved on the skill, so the game recognizes it as valid.

I've tried to break the target's armor first with Armor Piercing Rounds, but that doesn't change the result.

Tested on a level 42 Gemling Legionnaire in The Matlan Waterways map, with a Bombard Crossbow basetype rare crossbow. Tested both with other support gems equipped to High Velocity Rounds, and also with it alone in its slots. The High Velocity Rounds skillgem has been Lesser Jeweler's Orb'd so it has 3 slots in it.

Its probably because of a hidden subtext of skills that consume break armour can't break armour themselves under splinter, and this should of been restricted.

I really hope this is a bug and it works together, it would be so sweet.

Hidden subtexts are irrelevant. If skill or support doesn't explicitly state that they can't be used simultaneously (like some other skills/supports do), then High Velocity Rounds + Splinter Support Gem combination should work without issue.

I agree they just shouldn't allowed to be socketed together, but I think you can read the thing when you hover over "Payoff" on any payoff skill, basically says that payoff skills can not inflict the ailment they consume