COAL using CBTO from Hornady OAL gauge significantly shorter than book COAL?

[Rob01]

Thanks to everyone for their input! To clarify, I’m not referencing COAL trying to match it, I know that every rifle is different. That being said, it rang alarm bells when I was .3 shy. The rifle has been an absolute tack driver to date, so I don’t think it’s an issue with the chamber or barrel. As per my previous comment, I think it’s an issue with the modified case.

When I get home I’ll try to run it through an expander and/or polish and sand the throat and report back.

Yeah if you have shot factory ammo through it then there is no rifle issue. Just a tight neck modified case. I am sure you will get it working fine.

 

[Reformedcitykid]

Gents, glad to report back with some good news! As suspected, it was an issue with the modified case neck. I sanded it down until the bullet slid freely, and took 10 measurements:
2.3230"
2.3270"
2.3260"
2.3275"
2.3270"
2.3260"
2.3250"
2.3230"
2.3245"
2.3260"
For an average of 2.3256" aka 2.3255"

Any recommendations how far off the lands to start loading? I've read from .01" to .04", if anyone has a compelling argument one way or another please let me know!

Once again, thanks for everyone's input!

 

[Rob01]

Gents, glad to report back with some good news! As suspected, it was an issue with the modified case neck. I sanded it down until the bullet slid freely, and took 10 measurements:
2.3230"
2.3270"
2.3260"
2.3275"
2.3270"
2.3260"
2.3250"
2.3230"
2.3245"
2.3260"
For an average of 2.3256" aka 2.3255"

Any recommendations how far off the lands to start loading? I've read from .01" to .04", if anyone has a compelling argument one way or another please let me know!

Once again, thanks for everyone's input!

Good to hear.

Disregard. Went back and saw a 140 SMK. I’d go .020” off lands but SMK don’t mind jump.

Some advice though? I would get a better bullet with a better BC. That 140 SMK is a turd for bc in a 140 6.5 realm. Lots of better choices.

 

[Bill Norris]

Gents, glad to report back with some good news! As suspected, it was an issue with the modified case neck. I sanded it down until the bullet slid freely, and took 10 measurements:
2.3230"
2.3270"
2.3260"
2.3275"
2.3270"
2.3260"
2.3250"
2.3230"
2.3245"
2.3260"
For an average of 2.3256" aka 2.3255"

Any recommendations how far off the lands to start loading? I've read from .01" to .04", if anyone has a compelling argument one way or another please let me know!

Once again, thanks for everyone's input!

Recently worked up a couple of loads for a friend of mines 6.5CM and started load development @ .010 off the lands. Checked it at .007 and .013 off the lands and .010 was what it wanted to shoot.

 

[Straightshooter1]

Good to hear.

Disregard. Went back and saw a 140 SMK. I’d go .020” off lands but SMK don’t mind jump.

Some advice though? I would get a better bullet with a better BC. That 140 SMK is a turd for bc in a 140 6.5 realm. Lots of better choices.

I have some 140 SMK's and couldn't easily get them to perform very well. I went to the 142 SMK's and they're grrrreat! Unlike the 140's, the 142's are factory tipped, which may be one of the reasons they've done so well for me.

 

[Reformedcitykid]

Good to hear.

Disregard. Went back and saw a 140 SMK. I’d go .020” off lands but SMK don’t mind jump.

Some advice though? I would get a better bullet with a better BC. That 140 SMK is a turd for bc in a 140 6.5 realm. Lots of better choices.

What would you recommend?

 

[Rob01]

What would you recommend?

The 142 SMK mentioned and the 140 ELD-M would be two good choices.