Have an Olympic Arms lower with a 16 inch Douglas Barrel. Less that 100 round fired thru it. After a thorough cleaning it will feed and fire Federal Factory ball ammo OK. PMC ball will leave the case in the chamber and fail to eject. The extractor breaks the side of the case off and leaves the case in the chamber. A cleaning rod thru the bore will push the fired PMC case out with little or no effort (just the weight of the rod) - Would appreciate any information as I consider you guys the experts. - Thanks in advance.

What type of chamber does that Douglas 16" barrel have? Is it chambered for the 5.56mm or the .223 Rem.?

You might want to check out the "Ammo Faq" tacked to the top of the ammunition forum as you might be trying to shoot 5.56mm rounds in a barrel chambered for a .223 round.

Mike

You probably have a nice tight chamber.  This is really good for precision shooting with handloads but a little finicky for generic ammo.  I have read that polishing the chamber with flitz, a bore mop, and an electric drill can work wonders.  You might search for some threads on this board.  Again, the idea is to polish not to make it bigger.

You might see signs of a rough chamber printed on the fired shells.

I'm sure someone will point out the difference between 223 and 5.56 but I've never believed that argument.  

Your Douglas barrel is chambered 223 REM, and your trying to feed it 5.56 NATO Ammo.  The 223 REM chamber is tighter in the throat lead area.  This means that when the 5.56 ammo is loaded, the bullet is jamming into the rifling, and causing the normal load to be over pressured due to the bind.

You have one of two options.  Either send the barrel back and get a 5.56 NATO chambered barrel, Or shoot the ammo that the barrel was designed to shoot, which is 223 REM.  Since it's a Douglas barrel, the idea of re-reaming doesn't make any sense, since the barrel is a match type, and over size reaming is just wasting the true potential the barrel.

Thanks guys !!!!!!!!!

Sometimes it pays in dividends to respect your elders and in this case, Oldguy has made the most sense.  Check your brass to see if they are rough of appear to have marks left by a burr in the chamber or something else that would make the brass stick.  In fact, if you want to test it out, take a piece of the brass that was stuck and use a permanent black marker to cover the outside of the case.  Then throw it into the chamer and release the bolt.  Pull the brass and see if there are any spots on it where the marker wore off.  It might also help to mark your 12 o'clock position on the brass.

If you find a burr, take the barrel to a gun smith and see if he can finish it.  I'm a little wary of using an electric drill and flitz so close to the throat, but that doesn't mean his idea doesn't work.

The 223/5.56 dilemna isn't that big of a deal.  Break in that barrel with a couple hundred more rounds, then if it's still a problem, consider a new barrel.  However, I think that after further break in, it'll shoot just fine!

One thing we have not checked out yet: Are the cases showing any signs of high pressures? Things like cratered primers, pierced or leaking primers, a little button of brass extruded into the ejector plunger hole, and so on? These are indications that you do have high pressures, which will extract hard and cause ripped rims. A civilian throat with military ammo can cause this... So you can shoot suitable ammo or have a military reamer put into it, which seems a shame for a good barrel like this has.

The concerns about getting abrasives into the throat are valid with some polishing agents, but not others. I feel that polishing is important in autoloading rifles, while some other folks think that it is unnecessary...

I know some folks who use Flitz on a mop. Flitz is probably OK. If you get some on the throat, just patch it out. JB won't hurt barrels and I doubt it will polish the chamber much, but some folks swear by it.

I use a tapered wooden dowel with slit in it and use 220 wet-or-dry. Polishing this way should be on the body only. You can get onto the shoulder, but it won't do any good up there, and trying to do the neck is an invitation to messing up the throat, so just do the body.

Remember that all you are trying to do is take off the meat hooks (high spots, asperities), not change size or make the chamber bright. It is always easier to do this with the barrel off of the upper, but it will work with it installed too.

Try some commercial ammo, and maybe polish the chamber, and try the rifle out. If you have no high pressure indications, the chamber is polished, and you still rip rims off, do not despair, just get back with us and we can go from their.

Tried the markslot on the fired case and the coating was thick enough to stick the case in the chamber. It took a cleaning rod down the bore to get it out. No marks on the case so the chamber is smooth. It will shoot any US Made Ammo just fine it is the PMC or other similar Foreign ammo that stick in the chamber. I bought a Wilson Case case and found that some of the PMC was not as it should be. Thanks a lot for all the information. I am going to stick with the USA made ammo and forget the other ammo. I like the tight groups. - Thanks again.