I had a handful (maybe a dozen) DD rifles pass through my place last year, along with a modest amount of sights, accessories, and a few LPK's. I definitely wouldn't consider it a HUGE amount, however, and was surprised to see a few of these shortcomings.
The first was a CH that was immediately swapped with a BCM GF, so it wasn't a huge issue, but the charging handle was definitely binding while cycling the BCG and you can clearly see the tooling 'drift' to the left at the end of the cut. I sat it aside for a few months and kind of forgot about it.
http://i96.photobucket.com/albums/l1...F8FE93441E.jpg
While assembling a lower from a DD LPK, I ran across this little gem
http://i96.photobucket.com/albums/l1...F9033A10E8.jpg
I didn't like to see a few oddities like these from them but if you're making widgets for a living, you're bound to make a few goof-ups from time to time.
I called and spoke with a gentleman that was fairly surprised that I was telling him a pin was that much too short giving me a 'Whaaaaaat?' I offered to send pics and also told him about the CH from previously. No questions asked, didn't want to see pic, just got the new parts headed my way the next day. Back in business!
http://i96.photobucket.com/albums/l1...F8F6E9DF85.jpg

