308?

[andrewst35]

I finally shot my 308 today and did well. When I got home, I measured the once fired brass using the rcbs case mic. According to the directions, saami specs are min 2.160 for headspace when measured at the shoulder. My brass measured 2.61 when I used the mic. Is this ok? Do I have a tight chamber? I bought the rifle used, so I don't think it was shot much. Also I noticed when I loaded the rifle, the third round was offset. Does this mean I have a stagger feed? Thanks!!

[darkker]

The fact that (what I assume is factory) brass is not min spec is not unusual.
If your brass is LONGER than min, that is not a tight chamber.
SAAMI max OAL for cases is: 2.015"
SAAMI min is: 2.005"

Trim your brass. IF your brass is longer than SAAMI max, AND you aren't interfering with the expansion, meaning the chamber is larger than spec; you either have a "out of spec" barrel from the factory; or the more likely culprit is that the gun had previously been shot with hot loads(or a ton of rounds) and it has been stretched, or worn loose. Overpressure loads will open up headspace with relative ease.

[stangfish]

Your are quoting two numbers that are .450 apart. I am not familliar with the RCBS directions but a Saami print says the datum is 2.634 +0/ -.007(or 2.627 - 2.634). I am not happy with your numbers. I hope you are just unfamiliar with the gauge and are getting bad readings.

http://media6.dropshots.com/photos/493614/20100507/b_194151.jpg

[barrel-nut]

The Precision Mic comes with a base and two top pieces; each threads onto the same base, but they are different, and have different purposes. Specifically, the size of the hole bored in the end of the top pieces are different sizes. One is intended for checking bullet seating depth using the supplied dummy round. The other has a larger hole and is intended for measuring headspace. Are you using the correct assembly?