Criterion 6mmBR I took chamber measurements

Got my new Criterion 6mmBR 8tw headspaced this evening and did some measuring.

If anyone sees something that doesn't seem right, jump in and let me know.

Using a Hornady Lock-n-Load OAL gauge I got these results.

Berger 105VLD 2.427"
Sierra 107 2.390"
A-Max 105 2.324"
A-max 87 2.262"
A-Max 75 2.203"

I am using NEW paper box Lapua brass that the OAL is 1.556". Using the above measurements this would mean that:

A-Max 105 had .456" in the case (bullet lenght 1.224" )
Sierra 107 had .401" in the case (bullet lenght 1.235")
Berger 105VLD had .363" in the case (bullet lenght 1.234")
A-Max 87 had .334" in the case (bullet lenght 1.040")
A-Max 75 had .290 in the case (bullet lenght .937")

Using a Sinclair chamber lenght gauge it measured 1.578" and the measurement to the lands with a Berger 105VLD was 1.668"
To the lands= 1.668"
Chamber lenght= 1.578"
Freebore = .090

Old paper box Lapua brass has the shoulder .003" farther forward then the new Blue box I have. Measurement to shoulder 1.068" old brass / 1.065" new brass. Which leaves the new Blue box brass .003 shorter in OAL then the old brass. This was measured in a Hornady head space gauge using Sinclair SS inserts. OAL old 1.556 OAL new Blue box .1553

not sure what you are asking,
fireforme your brass first ,then bump your shourders back a thou. if needed

It was just informational for anyone to see. The only real question I had is did I figure freebore correctly.

Thanks,

Cover

sounds good

Cover Dog,
According to Criterions print the freebore is .093. I would say you are very close. After you run a few rounds (50 - 100) through your barrel you may see a slight radiusing of the now sharp angles - you will have a little more freebore at that time.

Enough of this talk, how does it shoot?

Jim Briggs
NSS

We still have quite a bit of snow on the ground, and this weekend all rain. From the looks of the bore it should shoot great. I'll give a full report once we start sending bullets down the tube.

Cover Dog,

I'm in the same boat as you... I can't wait to get my new Criterion 6mmbr down to the Grand River range.... I saw your forecast and thought that sounds a lot like mine and it is since we're about 20mins apart! Next nice day, we may be breaking in like barrels simultaneously! I know I'm not taking this beautiful barrel out in this nasty rain/flooding!

dperk....glad to hear from someone else in the neighborhood. I am a member at Crooked Creek Conservation Club and if I don't shoot here at home, I shoot there. Can't wait for spring.

sounds like you guys should meet up for a barrel break-in day!