6ARC barrel in my AR15 actually throated properly

[fatelvis]

In 40+ years of shooting and reloading this is the first time I've ever bought an auto rifle (really an upper) that had a throat that actually was cut correctly in my book. This is a Cmmg 100 series Resolute upper in 6 ARC. Up until now every auto I've ever had possessed a throat that was SO LONG that you couldn't possibly reach the lands of loading to magazine length. I just sized some once fired brass with a 4K shoulder bump and found that the 87 Vmaxs were seated out too long and weren't letting the bolt close all the way. They are touching the lands at 2.152" OAL. Myself, I'm tickled that I can actually seat close to the lands and still be well under mag length. Is this a good thing, or is this unusual or in some way a bad thing? Just hoping I'm noy overlooking any red flags. Thanks Guys!

 

[David Milisock]

Sounds nice for varmints. Watch your brass, check for marks of rough handling.

 

[Oso]

The standard 6ARC Reamer is designed for 105gr HP and 108gr ELD bullets at AR15 mag length. It is possible that due to different bullet geometry (length & location of ogee) that both these heavy High BC bullets and the 87gr VMax works out without a big jump. How is the seating depth on the VMax?

Caveman Logic: Try loading a factory Hornady 105gr HP cartridge to see if it fits your chamber. If the bolt doesn’t fully close then the chamber is throated short. Not a big deal if you are not planning to use the heavy bullets.