You might be interested in a little email I sent off to the ATF requesting their position concerning angled forgrips on AR pistols since I was considering the purchase of one. Yes, I was dumb enough to actually email the ATF regarding controversial policy and was surprised to receive a timely response.
Disclaimers: I'm some random interwebs person with three whole posts here. I could have made all of this up. I didn't, but I have no way of proving this. I will, however, post my original send and the ATF response. From there, it's up to you.







I'm also surprised it was so straight forward after sifting through some of the results I've seen. If this isn't news to you, you got me. I wasn't able to find much of a concise answer after my search on the topic.
Even discussions over the letter referenced above (link fixed) were full of dispute and worry that it wouldn't apply to anybody else but the addressee.

Maybe you'll find it useful, too.

Your linky no worky.

Page 3

Linky

You can put a VFG when the OAL of the pistol is over 26", in which the classification of the gun is no longer a pistol - but a firearm.

Somehow got an extra http in there :p. works now.
You correctly interpreted the intent, however. Thanks :D

I keep a copy of the Tech Letter addressed to me in my AR's bag.  It covers everything I have done as well as my future plans.

See the standing thread on scanned letters from the BATFE at the beginning of this AR Pistol Section.  The thread is from iNeXile556 on this topic.  This is great thread to search for all your ATF questions.  If you have a question you can bet someone else had the same question.  This thread may save you from waiting for an ATF answer.

DAMN YOU STICKIES! DAAAAMN YOU!
Surprised i didn't find that on my trawl through google. Probably keyword failure.

The turnaround time was actually pretty reasonable. 3-4 days by email, tops. But yeah, i didn't even get past the first page of that stickie and there was my answer. Probably doesn't hurt to get a personalized response anyway. Guess that means this dem dar thread is offical dun. :)