Looking at the picture of your formed empty case in your chamber leads me to believe that your not forming the shoulder back far enough on the case, this could likely be the result of using a shell holder that has got ears that are to high and are contacting your die body before the case is inserted far enough into the die.
This has been a issue for many people who have been trying to form brass on a progressive press but was resolved with some serious cam over of the ram, if your forming brass in a single stage press what shell holder are you using? mainly brand, as this may just be a compatibility issue between the die/shell holder rather then a quality control issue from a company with a past history of quality control issues
Running off a single stage press with LEE dies and Lee shell holder. Cases were sized, rotated 90 degrees and resized again before final trimming.
Hornady LNL case gauge using 350B insert measures 1.060"-1.064" to the shoulder compared to Barnes Vor-Tx factory ammo which measures 1.062" with the same gauge (this from my research and image posted in the reloading thread, I do not have that ammo on hand so I'll take that measurement with a grain of salt).
Cases trimmed down to 1.358" in keeping with SAAMI specs and also Hornady's recommended trim length.
Case neck width with a 155gr SMK and 155gr AMAX is 0.332".
From Hornady reloading manual, 155gr AMAX seated to 2.220" COAL. Ammo does not chamber as it hits the lands. Needs to be seated to 2.052" COAL to clear the lands and fall freely (or light tap) from chamber.
From Sierra reloading data sheet, 155gr Matchking seated to 2.105" COAL. Ammo does not chamber as it hits the lands. Needs to be seated to 2.05" COAL to clear the lands and fall freely (or light tap) from chamber.
From all my measurements, I think my cases are sized within SAAMI specs BUT again, hence the reason to confirm this with factory ammo. Go/no-go gauges have been ordered as well and should be here in a couple weeks.
I'd gladly accept the fact that I'm wrong 'cause trying to find a replacement 11" to 12.5' 300BLK barrel is like finding a unicorn.
We should probably move this to the reloading thread in keeping with the Ammo guidelines.
