Nosler 280AI factory ammo cleaning

[Bob Wright]

Bought 100 rounds of factory Nosler 280AI 140 gr. BT ammo to break in new build. 100 yard groups not too impressive, but just wanted the brass for load development.
The problem with developing a load became apparent with wild velocity caused flyers.
I noticed when I cleaned with 50/50 vinegar/water and a splash of detergent this reliable cleaner wouldn't touch the black carbon in the case.
I reloaded for the ladder test in .2 gr increments. First group at 200 was 1/8th inch.
Next two sets of charges were everywhere with crazy velocities throwing flyers (+70 fps.
Stopped shooting and pulled one round. It was like it was glued to the brass destroying the the 145 Barnes LRX bullet. Only 24 hours elapsed.
Next day,
I turned all necks, and polished out the neck interior back to brass from this carbon. Reloaded all exactly the same in 3 groups, same round count.
All went well after.
Whatever powder from factory loads left that deposit, without getting it out, it was impossible to predict speeds/get groups.
Ever see this before?
I just received new brass from Nosler that will be inspected and prepped as required and I suspect it will go a lot smoother on a different bullet I'm working up.

 

[Dmagna]

The Nosler 280ai loaded ammo brass is different from their bought custom brass FYI.

 

[Bob Wright]

The Nosler 280ai loaded ammo brass is different from their bought custom brass FYI.

I just got my box yesterday. It has about .001" thicker neck wall but haven't inspected weight, headspace etc...shipper was pretty rough on the box and will probably run them through dies anyway. Such is life.

 

[Dmagna]

I just got my box yesterday. It has about .001" thicker neck wall but haven't inspected weight, headspace etc...shipper was pretty rough on the box and will probably run them through dies anyway. Such is life.

The two types of brass has different capacity. There is an indentation on the inside of the head of the case on the loaded ammo, there is no indentation on the custom brass. I didn't realize this until I tried load development. I couldn't get the gun to group until I took out all the loaded ammo brass out and only used the bought brass

 

[Bob Wright]

Yep, went and looked. It is raised on the loaded ammuntion brass and flat on the new brass from Nos.
Guess that is a tooling feature for punching the flash holes vs. drilling flash holes. My intent was to keep these brass seperate but a chance some will get mixed. Now I'll peek into them to make sure what I am loading in the future.