Warning

 

Close
Confirm Action

Are you sure you wish to do this?

Cancel Confirm
AR15.COM
AR Sponsor
6/18/2010 2:37:51 PM EDT
Ok, I just built my first AR.  Got a spikes lower and a DTI complete upper.  I have everything together but I can only pull the carrier back about 1 inch and then it stops.  What could be wrong with this?

Terry
6/18/2010 2:53:40 PM EDT
[#1]
Separate the upper and lower.  See if the BCG slides freely back and forth.

Carefully go through the functions of the lower parts to check for proper function.  Careful in that you do not want the hammer to drop unrestrained onto the lower/bolt catch.  Stick a wad of paper towel or old foam earplug in front of the hammer just to be sure.  Offhand suspicion is that you might have the disconnector spring in wrong and that's holding up the hammer from moving all the way back, or some other problem with the fire control parts installation.

If the fire control all checks out, try the buffer for free movement.  Pull it out and make sure you don't have something wrong like a rifle buffer in a carbine tube.
6/18/2010 2:59:49 PM EDT
[#2]
Your hand is weak!
Is your buffer sticking ?
is there a round in the chamber ?
will the bolt come out of the upper when the gun is open ?
is the buffer detent pin sticking up to high ?
is the charge handle sticking ?
.
tell us more
6/18/2010 3:02:00 PM EDT
[#3]
are pics possible?
6/18/2010 3:26:01 PM EDT
[#4]
Everything is new and there has never been a round even near the gun yet...
Here is as far as the carrier will come out
http://i197.photobucket.com/albums/aa7/tms217/Gun/DSC02885.jpg

Here is the lower, everything looks like it works great here...
http://i197.photobucket.com/albums/aa7/tms217/Gun/DSC02886.jpg
http://i197.photobucket.com/albums/aa7/tms217/Gun/DSC02887.jpg

Here is the upper, this is as far as I can get it to move by itself
http://i197.photobucket.com/albums/aa7/tms217/Gun/DSC02888.jpg
6/18/2010 3:31:41 PM EDT
[#5]
your bolt maybe stuck in the chamber some how, try spraying some lube in and see if it loosens it up.
6/18/2010 3:48:46 PM EDT
[#6]
I would put it all together and then hold the rifle so the muzzle is pointed up.  Tap the buttstock on the floor slightly as you pull on the charging handle at the same time.  Sometimes the extra force of the rifle hitting the floor will assist with opening.

Even though it is "not loaded", don't let the muzzle point at your head or anything else valuable.

If that works, I wouldn't reassemble it until you figure out exactly where you went wrong.....
6/18/2010 3:48:59 PM EDT
[#7]
Did you assemble the upper or did it come barreled?

A barrel/barrel extension that's not straight in the receiver can create a situation where the bolt is still engaged on the locking lugs even when in the unlock position.

Try wiggling the bolt carrier a little in rotation and see if it will then allow movement to the rear.

The distance that it's moved to the rear is indicative of this kind of problem.
6/18/2010 4:33:42 PM EDT
[#8]
Is the firing pin in the BCG?

If it's not, the bolt  cam pin can rotate and lock up in the reciever
6/18/2010 4:51:09 PM EDT
[#9]
Or, this would be a good excuse to send the upper back to DT for a refund so you can order a Spikes upper.
The lower married down you know.
6/18/2010 5:09:35 PM EDT
[#10]
Its hanging up while its off the lower? Guess its not the hammer spring.

Take two shots of Mobile 1 and call me in the morning.
6/18/2010 5:36:47 PM EDT
[#11]
Looks awful dry in there... in addition to the other suggestions, give it some lube.
6/18/2010 5:40:56 PM EDT
[#12]
I have a rifle do that once, I had to file down a VERY SMALL amount of metal off the outside corner of the cam pin.  Your problem sounds and looks like the issue I had... maybe the corner of the cam pin is hitting the inside wall of the receiver.
6/18/2010 5:52:41 PM EDT
[#13]
Wow this forum is great...  Wit some work said above I was able to get the bolt carrier out.  It was dry as a bone in there.  Oiled things up real good now seems like no issues.  I didnt assmeble the upper DT did.  This will be lesson learned for me..  Oild the hell out of it...

Thank for everyones help

Terry
AKA Newbie
6/18/2010 5:55:50 PM EDT
[#14]
I've heard someone had the same problem. It was his forward assess spring had came loose inside his upper.
6/18/2010 5:57:01 PM EDT
[#15]
Quoted:
Ok, I just built my first AR.  Got a spikes lower and a DTI complete upper.  I have everything together but I can only pull the carrier back about 1 inch and then it stops.  What could be wrong with this?

Terry


Nice day-glo paint.
If the BCG will not go into battery it could be your gas tube FSB / block is mis-aligned, or too far back.  You have a end cap?  If not add .050".

I think your FA is assembled incorrectly, or has a broken prawl.  Lay it on the Right side, you should be able to remove it.  Lay it on it's Left side and put
the bolt back in and you can hear the prawl rattle over the rack cuts.  After you get the BCG out you may be able to see or feel it in the BCG's bore.

How do I know this?  I'm holding the first on I've ever seen.  Just got the bolt out.  The prawl seems independent of the FA
458
6/18/2010 5:58:33 PM EDT
[#16]
Quoted:
Wow this forum is great...  Wit some work said above I was able to get the bolt carrier out.  It was dry as a bone in there.  Oiled things up real good now seems like no issues.  I didnt assmeble the upper DT did.  This will be lesson learned for me..  Oild the hell out of it...

Thank for everyones help

Terry
AKA Newbie


Even with absolutely no lube .   You should still be able to easily slide the carier group out of the upper with the upper off the lower .   something isn't right.
6/18/2010 6:18:44 PM EDT
[#17]
looks as though your buffer stop plunger is too high,oops never mind.oil is good
6/18/2010 6:20:58 PM EDT
[#18]
Quoted:
Is the firing pin in the BCG?

If it's not, the bolt  cam pin can rotate and lock up in the reciever


This is what I'm thinkin'
6/18/2010 7:16:05 PM EDT
[#19]




Quoted:

Is the firing pin in the BCG?



If it's not, the bolt cam pin can rotate and lock up in the reciever




This is a harsh lesson to learn.  Glad it worked out for the OP though.
6/18/2010 7:56:45 PM EDT
[#20]
Huh?
Did I miss something
458
6/19/2010 3:07:36 PM EDT
[#21]
Quoted:
Or, this would be a good excuse to send the upper back to DT for a refund so you can order a Spikes upper.
The lower married down you know.


This



AR Sponsor