Angled and vertical foregrips - line of demarcation?

[Perplexed]

I googled it, but either I'm using the wrong search words or my google fu is just too weak today. Does anyone know at what point an angled foregrip stops being angled and starts being a vertical foregrip? Is 89 degrees the transition point, or are there parameters other than the angle of the grip relative to the barrel / hand guard? Being able to wrap the hand around the grip, or what?

 

[D. Hargrove]

So, I dig and dug and called a few peeps. Nothing other than the apparently obvious answer you have already given. To quote a friend that is in the business "um, any degree of angle off the 90 deg axis of the handguards is obviously angled." So after telling him he was a prick and hanging up, I assume your assumption is correct. Sorry I could not get more informative data.

 

[Perplexed]

Thanks for checking. I can't imagine the grip angle is the only determining factor, otherwise there would be a market for 89-degree grips for people who want to put such a foregrip on an AR pistol without needing to fill out, and get approved, the AOW paperwork.

 

[Perplexed]

No one else has any info about this?

 

[O4L]

Call or email the ATF.

 

[Perplexed]

Call or email the ATF.

I know I can do that; I was just hoping someone else who already did, or got the answer elsewhere, would pipe up.