I’ve purchased a pre-ban AR from the auction site gunbroaker.com.
It’s a standard .223 and has E.A. marked on the receiver.  It’s an M-4 style gun with a new barrel.

I took it out to the range, fired it, but it wouldn’t cycle the next round properly.  The next round will feed at a 45 degree angle and jam up between the bolt and the interior of the upper.

It sometimes has trouble extracting the spent cartridge too, other times it flings it 8 feet away from the gun.  The strange thing is that the gun even has problems cycling manually.  I can pull the charging handle with full rounds in the mag and it will double feed, jam, and fail to extract.

I’ve tried everything I could think of and have the skill to do.
I’ve swapped out magazines, the entire bolt, even the entire upper receiver!
And it still won't cycle manually, much less fire.
I even took it in to a gun smith who couldn’t figure out the problem either.

I'm out of options here!

My question is:
1.Does anyone have an idea of what the problem could be?
2.My extra parts are coming from a Colt post-ban “Match Target HBAR”.  Could the differences in parts be voiding out my tests?  Are the parts compatible?

I appreciate any response!

Thanks,

Chris Ludwig

It could be several things, and these were problems I have personal had, and how I dealt with them:

Double feeds:
Magazine feed lips were too far apart, and the 2nd round would be fed when the bold picked up the 1st round.

Closed the lips with pliers, and checked them with another friends USGI 30.  No more doubles......and now I Have over a dozen magazines, instead of just one....:)

Jam/45 Degree Misfeeds:
I had a flat top upper, and M4 type barrel, but the knuckel head that built it, used rifle extensions. so the rounds were bumping against the "lip", before it went into the feedramps.

Solution:  I "dremmeled" the feedramps, by cutting into the extension.......and now its looks like this, on a previous thread:
www.ar15.com/forums/topic.html?b=3&f=118&t=191733&page=4

For other problems....perhaps other members can chime in....

first question, what type of mags are you using?
Get some USGI mags and try your weapon with those. My money is on the mags.

mag...buffer.........springs........ firing pin retaining pin hanging out...... does the bolt/carrier move easily in the upper when seperated form the lower?