View Full Version : AR Trouble, need advise

July 5, 2005, 12:38 PM
I came accross an rock river lower and put a model1 upper 16" crome 1:7 "M4" style upper on it. With a Model1 bolt carrier.

Lower was used but in excellent condition, less than 200 rounds fired from it.

After sighting in and putting about 100rds through I started having extractor problems. Brass sticking in the extractor and the open end of the can snagging on the lip of the ejector port efectively jamming open the bolt and preventing feeding/chambering the next round. Or the neck of the empty cleared the lip of the port but stayed in the ejector until the bolt caught the can sideways and clamped it sticking out of the ejector port again jamming the bolt partially open and stopping semi-auto action.

Any thoughts? :confused:

July 5, 2005, 01:13 PM
tear the bolt down, clean and scrub it well, look for burrs, rough edges on the extractor, etc.?

check your ejector for problems?

clean the gas tube?

use quality ammo?

try asking the question on the smithy forum. I've got plenty of good advice from the experts there.

July 5, 2005, 04:14 PM
Stovepipes (where the brass is left hanging out of the ejection port with the bolt closed on it) are usually caused by a weak ejector. As the bolt comes back, the ejector is too weak to kick the brass out before the bolt starts forward again.

You can check this after cleaning byt takiing the rear of the firing pin or an empty cartridge case and pressing down on the ejector. It should have good spring tension and move freely.

July 6, 2005, 03:00 PM
First of all, thanks!

I'm using factory Winchester 55gr FMJ so I think the ammo quality is probably not the issue.

I will clean the crap out of the bolt assy and check for burrs and weak ejector (spring I assume?).

If the ejector seems weak, do I replace the bolt or just get new springs? The bolt is brand new.

Thanks again.


July 6, 2005, 10:31 PM
sometimes a sliver of brass gets jammed under the extractor

July 7, 2005, 08:02 AM
If you have a weak extractor, usually you just replace the spring. It could be that there is just gunk or packing grease in the extr.

4V50 Gary
July 7, 2005, 11:19 PM
I'd clean out the ejector hole in the bolt with solvent and look down it for obstructions. Also measure the spring against a fresh one (line them up). Make sure the ejector and the spring move freely up and down and that it is nice & stiff. If it still has ejection problem, then replace the spring.

July 8, 2005, 12:05 AM
Sounds like an ejector problem to me, too.