Is my Type 2 chamber not Type 2?

[StoneHendge]

The Hornady tool is only a comparator, not meant for absolute measurement. It is good to have a headspace guage to zero from, (a standard) that is what I do with my .308's.
As long as you are using the same calipers, and same bushing, you should get very usable dimensions. Also depends on how consistent your "touch" is, but as long as one doesn't try to use calipers for a monkey wrench they should be within .001-.002. Won't get much better with calipers.

Yeah, but the comparison to SAAMI spec is an important one since I'm on the fringe (I don't care about LBC spec - the 1.225 was probably for legal reasons, an inside joke or a combination thereof). Having the NAPA caliper give me a lower reading made me feel better - and that caliper gives me a much "firmer" reading. I'm hoping to get a few rounds through it Monday with the GB bolt, my JP bolt and my old bolt that Midway sold with the Stoner/Satern barrel. My guess is the JP will pull it in .001 or 0.002 and that the headspace is a few thousandths inside spec. I'll just be using 95 gr VMax's I had lying around loaded light. Then I can start convincing myself that the 1.230 outside spec dimension leaves room for tolerance stacking instrument error on top of that. I might be being a bit anal, but it's probably a common side effect from having a barrel blow up in one's face.

[grayfox]

SH, I'd still be leery because regardless of the headspace tool you're going from 1.2090 give or take to, what, 1.230, or?
That's a brass stretch of 0.021... whereas the ones I'm used to (and ones I now keep) are 10 thous or less.

With my 18" Arp brass went from the 1.209 (Hornady comparator) to 1.225/6 -- you're going even further. I didn't like that stretch, not one bit.
Just sayin'.

[bj139]

SH,
I hope we don't have to start calling you "The Decapitator".

[StoneHendge]

GF, the virgin brass is for my 243. I'm using brass that was from my 1.225 Stoner/Satern barrel for this barrel with a sprinkle of 1.220 JP thrown in. It's 2 lots that came from factory and about 40% has been through the wringer 6 times and it's holding up fine. An in spec barrel is in spec. Ones gotta have faith that the brass makers who are selling out of spec brass/ammo account for the potential stretch to spec, likely along with room for error with tolerance stacking.

[Mad Charlie]

http://www.redding-reloading.com/online-...comparator

I don't know if you know about these or not, and I see that our Grendel's aren't listed, but maybe a call to Redding will help. There could be a possibility that one of the other 6.5's may "cross over", or they will make whatever it needs to work with the Grendel. I do not have one of these, and have never used one, but the principle looks sound.

When it comes to absolute measurement, I will take a GOOD travel indicator over any set of calipers any day. Calipers are not considered to be precision measuring instruments in the world of machining, being generally used for low tolerance "quick and dirty" measuring, but for most handloading purposes are considered adequate. The experience I have gained from over 40 years of production and job shop machining makes me dislike digital calipers. I much prefer dial calipers'
or if my eyes could still see, plain old vernier calipers.

Like others in this thread, I have had the issue of "short brass in long chambers". When I built my Satern barreled rifle I measured factory Lapua cases at 1.205 with
the Hornady tool and fired cases at 1.220. I thought "holy crap, this can't be right". I thought I got a bad bbl. or mixed up bolt. I have since learned that 1.220 is supposed to be min. spec. and the chamber is OK. Then there is my AA chamber, fired cases come out 1.214. So I have been keeping fired brass segregated and sizing accordingly. I checked every case fired in the Satern chamber with a feeler wire for a while without finding any incipient separation issues, so now I just bump the shoulders back .003-.005 and call it good. I will be calling Pacific or Forster, since my dies are Forster, about a headspace guage to use for a standard to set up the Hornady tool, as I feel that the shorter the travel from zero with calipers, the better the accuracy, comparatively speaking. Another thing I do when measuring is turn the case 90 degrees and measure twice, sometimes case heads don't come out square and extractor burrs get in the way, if the measurement stays within .001 I call it good. I also like to de-prime with a de-priming tool before measuring fired cases.

Yeah,,I can see why you want to be extra careful with your handloading!