Necks

[Paddyd]

Have a CBI barrel in 6BR Norma.
Reamer print shows .272" neck.
Will I need to turn case necks or will there be safe clearance without?
Been loading for about 40 yrs now, but the 6BR is something I have zero experience with so thanks for your input.

 

[AGSHOOTER]

272 is a No Turn neck

 

[Paddyd]

272 is a No Turn neck

Thanks. I suspected that it wasn't required, but in this business take nothing for granted.

 

[jobhopper66]

Nothing really beats measuring a loaded round for comparison. I myself would be checking the chamber itself with a pin gauge just to be sure of that dimension. We can talk theories all day but it only takes a few minutes to check realities.

 

[243winxb]

Measure a loaded rounds outside neck diameter.

 

[Bill Norris]

Have a CBI barrel in 6BR Norma.
Reamer print shows .272" neck.
Will I need to turn case necks or will there be safe clearance without?
Been loading for about 40 yrs now, but the 6BR is something I have zero experience with so thanks for your input.

Ultimately depends on the brass but normally using Lapua brass there is no need to turn necks as loaded neck diameter normally will run @ .270 which gives adequate bullet release in most cases.

 

[NZ_Fclass]

Never had to turn Lapua, Norma or Alpha brass. My current 6BR has a 271 neck diameter and my 6 BRX, 272.

 

[Murray Brook]

Got 2 6 BR's, one built on a Rem 700 and another on a Sako A11 action. Both are chambered with a Manson reamer with a .2725 neck. Loaded rounds with Laupa brass mike out at .269 and Norma brass at .268. Lots of clearance on both brands.

 

[AGSHOOTER]

What is the preferred neck clearance for accuracy on the 6BR

 

[Bill Norris]

What is the preferred neck clearance for accuracy on the 6BR

Preferences among shooters vary with all cartridges. Most B R shooters like very little clearance while others like some F-class shooters like up to .004 to .006 clearances according to tuning of the individual rifle/load combos. I personally like @ .003 total clearance with my 6BRX.

 

[Clancy]

Have a CBI barrel in 6BR Norma.
Reamer print shows .272" neck.
Will I need to turn case necks or will there be safe clearance without?
Been loading for about 40 yrs now, but the 6BR is something I have zero experience with so thanks for your input.

Depends on the lot. Most are .268. Some .267 and some .270, but you’ll probably be fine with Lapua and almost definitely with PETERSON, which runs about .267.

Don’t get cute with clearances anymore. .003 is BARE MINIMUM for me.

 

[Clancy]

What is the preferred neck clearance for accuracy on the 6BR

.004

 

[ricco1949]

I always used .002 total clearance on LRBR rounds.

However I was never able to drop a bullet in a fired case.

Gonna enter the game again this coming season after a 15 yr hiatus with .004 total clearance on a new 6 BR build. See if that extra .002 can work some new magic.

 

[Kracken McGraw]

I always used .002 total clearance on LRBR rounds.

However I was never able to drop a bullet in a fired case.

Gonna enter the game again this coming season after a 15 yr hiatus with .004 total clearance on a new 6 BR build. See if that extra .002 can work some new magic.

Let us know if it makes a difference. I have just.0015 clearance on a 6x47L but still have a sine wave on the case neck.

 

[ricco1949]

In progress but I'll post results when warms up enough to do load development in MN Arrowhead.