Converting PPU 5.56 to .300AAC

[DomG]

@ 10% of the converted PPU brass goes out of spec when loaded. I've yet to measure the wall thickness of the troublesome brass.

I run ALL my rifle cartridges through the Lymen Chamber Checkers; after sizing, before priming, and after loading.

The troublesome converted PPU brass sizes-up and fits the chamber checker just fine, but after loading, @10% are a NO-GO.

I unload the troublesome cartridges and resize without de-capping, and try a 2nd time...still out of spec when loaded.

No problems with any other head-stamps.

Length is spec so wall thickness is the only possible culprit.

 

[nso123]

Will they chamber in the rifle?

 

[DomG]

Will they chamber in the rifle?

No, they stop short.

 

[Smokyrider]

I've converted PPU from time to time, wall thickness is the issue, I trimmed them to the shortest possible case length allowed to get them to work in my guns but ymmv.

 

[Omega]

Good info:

 

[DomG]

Good info:

View attachment 298632
View attachment 298633

Wow, thanks!

Will add to my library

 

[Omega]

This may help some, it was collated from different internet sources by me, so use at your own risk.

 

[Smokyrider]

The case length shows 1.368 with a .020 variance, I trimmed my PPU down to 1.350 to get them to work since I don't have a way to turn my necks.
Although lately I just buy primed 300blk brass from American reloading, 500 for $92 shipped. All I have to do is size (deprimer pin removed) and trim, so I very rarely resize 223 brass anymore but at least I can if I want to.