Machine gun fired Lake city 5.56 brass

[Balrog]

I bought a lot of this cheap for reloading. I have discovered about 20% of it wont size. Most of the 20% won't even fit into the shell holder unless I push hard, or diddle around with the case. Some cases will fit into the shellholder in one direction, but not if you rotate the case 90 degrees, so its like they are not even round, more like ovals. I have learned that if I have any trouble fitting the case into the shell holder, it cannot be resized. I pulled out my small base die, and tried it, but it still can't salvage them. I think the problem is the case head is out of round.

Is this normal for machine gun fired brass?

 

[paradox998]

By chance using a Lee shellholder? I have had lots of problems with LC brass in the Lee shell holder. Lee knows about it, but it does not seem to be getting fixed.

 

[Balrog]

Lee and RCBS. I did not notice a significant difference between the two.

Problem is, even if I get the case into either shellholder, after I size it, it won't fit into a case gauge.

 

[Myke_Hart]

The rim of the brass head gets smashed by the ejector/bolt and will go out of round.

They make machines to resize the head/rim on the brass. I use a dremel to grind the heads back on those that are just out of spec. I toss the ones badly out of spec.

I use a dillion case gauge to find the out of spec ones and toss them into a box for grinding later.

Those darn semi and full auto military guns are hell on brass.

 

[rg1]

Check the rims of your brass. Often they are slightly bent or have extractor marks that may make them tight in your shellholder. I use a smooth file to file case heads with bent rims flat and to remove any bad dings from the extractor.

 

[243winxb]

Is this normal for machine gun fired brass?

Brass fired in an M16A1 on full auto is the same as if fired in any semi, be it mini 14 , AR15 or Ar180. LC runs test with proof loads at high pressure, this expands the web area of the brass. The brass is sold as scrap. Some ammo is chemical treated to age the brass to see if it will fail on firing. Some of the auto firearms are shot till they fail.

 

[Balrog]

Brass fired in an M16A1 on full auto is the same as if fired in any semi,

Like I said, I am talking about machine gun fired brass, not M16 or M4 fired brass. This ain't proof loads.

 

[243winxb]

Have you heard of "roll sizing" thats what your brass needs. http://www.army.mil/-news/2008/08/22/11859-ammunition-testingrigorous-process-well-worth-it/index.html http://www.benchrest.com/forums/showpost.php?p=488137&postcount=69