View Full Version : Problems with a new 20" build

05-13-2010, 9:37 PM
Hello guys.
Well I just finished my ar bould last week and finally got to try it out today. Well I ran 50 rounds of Black Hills through it withought a problem. Then I started using winchester usa and after about 5 rounds it started to have problems. The gun wouldnt feed anymore, I would have to cycle the bolt after every shot, the same thing happend when I tried wolf. After I examined the rifle I found some carbon build up on the bolt, also i noticed that on the gas tube right where it comes out of the gas block it looks darkened, is this normal? Well does anyone have any sugestions as to what the problem might be? Any help is appreciated. Thanx.


05-13-2010, 9:43 PM
looks normal. maybe your gun needs to be fired more.

05-13-2010, 9:47 PM
How Lubed is your AR. When I first Got my Upper it was bone dry. Run AR's Wet (Not Meaning H20).
-I use CLP For pretty much everything and also a little Gun Grease.

05-13-2010, 10:25 PM
Check the carrier key screws to make sure they haven't backed off. As stated earlier, run lots of lube as well, especially during the first few hundred rounds on a new gun. It does look like a bit of a leak at the gas tube as well. A lot of guns run with leaks at the block/tube without any problems, but a smaller percentage do have issues. It just depends on how much pressure is venting out of that leak prior to the bolt cycling back.

05-13-2010, 11:12 PM
Thanks for the help.
I checked the keys and they were fine. I will try giving it a good lube and see what happenes, but I probably wont be able to fire it again until next week.

05-14-2010, 9:14 AM
Did you build the upper or is it "off the shelf" pre-built? Warranty?
Lube is important. Grease the four BCG contact points and bolt.
Check gas rings on bolt.
Could be alignment of gas block, may be clogged or miss-aligned. Metal burr clogging it up?
Just check the easy stuff first and then look to the more esoteric areas last.
Swapping uppers with another shooter at the range will help to narrow it down too.
Good luck.