6.5 Creedmoor Overall Length

[shaffer7mm-08]

I'm reloading Nosler .264 140 Ballistic Tips in my Christensen Arms Mesa and when I measure my bullet ogive it 2.795 and I loaded them to 2.765. My maximum load is 40.5 grains of IMR4350 and at 41.0 my bolt becomes stiff to work. At 40.5 grains I'm shooting .600. Nosler is loading theirs to 2.805.
My question is; is the overall length fine or do I have an issue with my chamber?

 

[QuietTexan]

It's common for measured seating depth to exceed standard specified seating length. Sounds entirely normal.

 

[mkk]

If I'm reading this right your CBTO is 2.795?

How far off the lands is that?

What is .600?? Group size??

 

[mkk]

The Nosler number your referring to is COAL

 

[Dmagna]

Are you sure that your terminology is correct? And did you zero out your caliper while using and ogive measuring tool?

 

[QuietTexan]

I read it that he measured BTO to the lands of 2.795, which results in a COL of somewhere in the 2.950-3.050" range. Might be real long at 3.150" since the boattails on the BTs are relatively short so they have a lot to work with in the neck. He's seating them at -0.030" off, for a 2.765" BTO.

Nosler is printing 2.805" COAL, and the SAAMI spec range for the 6.5 CM is 2.700-2.825"

2.900" feeds through multiple 6.5CM magazines fine in several of my rifles, so it's not necessarily a problem to load the CM long.

I don't have any 140 BTs on hand to confirm but I have several others BTs to check against - these are a tangent ogive bullet that has a longer bullet base to ogive measurement than comparable weight hybrid or secant ogive like anything made by Berger or the Hornady ELDs. A Berger 140 Hybrid is something like 1.4" long and has BTO of ~.7" and nose length of ~.7". A Nosler BT is more along the lines of 1.3" long, 1" BTO, .3" nose length.

 

[Rosebud]

I read it that he measured BTO to the lands of 2.795, which results in a COL of somewhere in the 2.950-3.050" range. Might be real long at 3.150" since the boattails on the BTs are relatively short so they have a lot to work with in the neck. He's seating them at -0.030" off, for a 2.765" BTO.

Nosler is printing 2.805" COAL, and the SAAMI spec range for the 6.5 CM is 2.700-2.825"

2.900" feeds through multiple 6.5CM magazines fine in several of my rifles, so it's not necessarily a problem to load the CM long.

I don't have any 140 BTs on hand to confirm but I have several others BTs to check against - these are a tangent ogive bullet that has a longer bullet base to ogive measurement than comparable weight hybrid or secant ogive like anything made by Berger or the Hornady ELDs. A Berger 140 Hybrid is something like 1.4" long and has BTO of ~.7" and nose length of ~.7". A Nosler BT is more along the lines of 1.3" long, 1" BTO, .3" nose length.

This !!! Could also explain the stiff bolt.

 

[biednick]

CA puts real long throats on some of their rifles. It's not a problem unless you're trying to feed from a mag and need to get real close to the lands. If your load feeds and chambers well and isn't showing pressure signs don't worry about the OAL. If the 40.5 load is really .6 MOA (as in repeatable 10 shot groups, not cherry picked 3 or 5 shot groups) I wouldn't mess with it.