I put a Daniel Defense Mil-Spec Collapsible Buttstock on my DD Mk18 SBR.  While shooting it yesterday, using Remington UMC 55 gr .223, it repeatedly collapsed on recoil.  It would not stay locked in position.  A couple of times it pulled out some moustache hairs (yes, I'm an old fart).  Has anyone one else had this issue?  If so, what was the fix?  Do I need to go back to a Magpul CTR?

Sounds like you picked up an old stock.  We figured out what was causing this and are happy to send you a replacement that won't do that any more.  Just email [email protected] and our our team will take care of it.

S/F

Joe

Thanks I will send an email.

Sent the email this afternoon.  Got a response from Daniel Defense dang near instantly.  Mine went out at 2:48 CDT and I received a reply at 3:07 CDT.  I just saw the response, so they won't be able to complete the process until Monday.  That is on me since I didn't see their reply until a few minutes ago.  The plan is to send me a replacement and I send the defective one back for them to checkout.  All at no additional cost to me.  

Outstanding customer service.