Warning

 

Close

Confirm Action

Are you sure you wish to do this?

Confirm Cancel
BCM
User Panel

Page AR-15 » AR Variants
AR Sponsor: bravocompany
Posted: 9/2/2015 11:24:01 AM EDT
Looking for a little help. Could not get an answer in the search.

I have built a the ugly AR. Yes 7.62x39 and having a extraction issue. At first I needed to use a screwdriver on the bolt to extract the spent brass. After some cleaning and shooting (about 100 rounds) I was able to slam, hard on the but stock while pulling on the charging handle to extract. Got really tired of this. I finally bought an 800 grit chamber hone and tackled the chamber with it. There was a big improvement. Brass will extract about half way and steel needs a slight slap on the butt to come out. I have a 400 grit on order. There is no rubbing on the mag. The primer strikes appear to be good. I've heard that DEZ barrels can be tight.
You can see a picture of brass here: http://img.photobucket.com/albums/v319/tonyo1/20150902_103020.jpg
Brass has very similar line as the steel. Just doesn't show on the picture.
20" barrel from DEZ and BCG
Most everything else is PSA.

Thanks!!
Link Posted: 9/2/2015 4:25:12 PM EDT
[#1]
What kind of gas block are you using?  Are you sure the gas block is aligned and there is no gas leak around the gas key on the bolt carrier or gas block.  What stock and buffer are you using?  In my experience 20" barrels generally are not over gased but you may not be getting enough gas to unlock the bolt and cycle the action.  If the chamber is out of spec and to tight you might be forced to send the barrel back to the manufacturer.  You might try polishing the chamber with Flitz on a barrel mop attached to a short cleaning rod attached to a hand drill.  I hope you have liberally lubed the bolt and bolt carrier as new AR-15's usually need to be run wet during breakin.

Maybe other members will  chime in but hopefully you have not voided your warranty if you purchased this barrel new.
Link Posted: 9/3/2015 12:06:12 AM EDT
[#2]
See those longitudinal marks on that steel case?  That's not a good sign for the chamber.

Take a live cartridge.  With your separated upper minus the BCG, drop the cartridge into the chamber, and force the cartridge into the chamber with your thumb or finger as far forward as possible.  Now hold the upper with the muzzle up.

Does the cartridge fall free with gravity?  If not, you have some aspect of the chamber that is too tight, or ammo that is too large.

Link Posted: 9/3/2015 7:28:12 AM EDT
[#3]
Do you know what size the gas port is?
Rifle, mid or carbine gas?
The pic of that case def looks like chamber ridges or roughness.
Link Posted: 9/3/2015 9:06:48 AM EDT
[#4]
This is my thought. Everyone keeps talking head spacing and none of the marks lead me to that conclusion. I do have a 400 grit hone coming in tomorrow. I'm not a professional gun smith. I do have an engineering background and I know those marks are not normal. I guess I'm just looking for someone else to say the same thing about the marks.
Link Posted: 9/3/2015 6:54:52 PM EDT
[#5]
Those marks generally to give one a sign of assurance, should have sent the barrel back if that was an option.
Link Posted: 9/10/2015 10:30:09 AM EDT
[#6]
Quick update. Talked to the barrel manufacture owner. They are going to look at my upper. They admitted that they had problems with the 20" barrel in 7.62x39. pressure, dwell and chamber tightness. They will work on this to try and make it work. If not...they are going to replace it with either an 18" barrel or 16" barrel. All I have to do is pay the shipping.

Since I've had it about a year I can respect that.
Page AR-15 » AR Variants
AR Sponsor: bravocompany
Close Join Our Mail List to Stay Up To Date! Win a FREE Membership!

Sign up for the ARFCOM weekly newsletter and be entered to win a free ARFCOM membership. One new winner* is announced every week!

You will receive an email every Friday morning featuring the latest chatter from the hottest topics, breaking news surrounding legislation, as well as exclusive deals only available to ARFCOM email subscribers.


By signing up you agree to our User Agreement. *Must have a registered ARFCOM account to win.
Top Top