Warning

 

Close
Confirm Action

Are you sure you wish to do this?

Cancel Confirm
AR15.COM
AR Sponsor
6/16/2009 2:36:16 PM EDT
I recently built an ar with a S&W M&P lower and a blackthorne products upper.  When firing the bolt jams on top of the next round.  I am using C products mags ( Green and orange follower).  If anyone has any ideas of how to correct this let me know.  Thanks

Fred
6/16/2009 2:51:56 PM EDT
[#1]
Single round loaded into a mag, the mag insert into the rifle, and the round charged/fired?

Did the bolt lock back on the bolt catch?
6/17/2009 12:23:33 PM EDT
[#2]
im gonna go ahead and say that the fact you have a blackthorne upper is the problem.  if you search you will find that most have problems with hesse/blackthorne/vulcan products.
6/17/2009 5:54:23 PM EDT
[#3]
when you pull the bolt carry assembly out does the bolt fell like it;s kind of loose or does it feel like it fits snuggly but still moves smoothly?
6/18/2009 11:31:43 AM EDT
[#4]
From what I've read it may very well be the Blackthorne upper but there are plenty of other culprits that could cause such a problem. Is your rifle well oiled?
6/18/2009 11:40:16 AM EDT
[#5]
The good news is that if it's trying to work but just doesn't have enough "umph" it's a very fix-able problem. Might just be the "newness" and it needs to be worked a little. I wouldn't panic over the "bad press" Blackthorne gets until you exhaust all other possibilities.
6/20/2009 1:26:19 PM EDT
[#6]
I also recently built a rifle using a Anvil Arms lower & a Blackthorne upper & was having the exact same problem.Rifle would eject the 1st round & short stroke & ride up over the second round.It did this to me at the range & I thought it just needed broke in,so I fought with the rifle & ran 300+ rounds thru it & it still would not break in.
   I borrowed a friends bolt & carrier group out of his Bushmaster & my rifle ram like a well oiled machine.If your bolt & carrier came from Blackthorne,that it your problem.They are ruff as a cobb & will not break in for some reason.
   If you have the extra bucks,I would suggest a Fail Zero drop in kit that is totally awsome.
6/23/2009 3:27:18 PM EDT
[#7]
Thanks for all the help guys. Im gonna start with replacing the bolt and carrier considering they are no machined well at all.  I let you know what fixes the problem
AR Sponsor