Criterion 6mmBR I took chamber measurements

[Cover Dog]

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

[drybean]

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

[Cover Dog]

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

Thanks,

Cover

[drybean]

sounds good

[northlander]

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

[Cover Dog]

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.

[dperk]

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!

[Cover Dog]

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.

[pdog06]

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