Rechamber 6.5 Creedmore to .260 AI

[A A Ron]

According to the chamber prints the 6.5 Creedmore is .4709" at the widest point on the case body. The .260 AI is .4714" at the widest point on the case body.

Question, is .005" enough material to keep a reamer centered when rechambering a mass production 6.5 barrel to a .260 AI?

Would setting it back a few threads increase the margin if the factory tolerances are too sloppy?

 

[fseaman]

Would a long pilot shaft on the reamer help hold it?

 

[lancetkenyon]

Might as well do the .260AI. Go for more gain since you are thinking about it.

 

[buckbrush]

I have both 6.5 Creedmoor and 260 AI. Juice isn't worth the squeeze in my opinion.

 

[FEENIX]

According to the chamber prints the 6.5 Creedmore is .4709" at the widest point on the case body. The .260 AI is .4714" at the widest point on the case body.

Question, is .005" enough material to keep a reamer centered when rechambering a mass production 6.5 barrel to a .260 AI?

Would setting it back a few threads increase the margin if the factory tolerances are too sloppy?

What do you hope to gain from your investment of time and money? I agree with @buckbrush

 

[fseaman]

What pills are you throwing with the 6.5CM and how fast?

What do you want to throw and how fast?

 

[A A Ron]

It's actually more of an investment to go 6.5 Creedmore. I have hundreds of pieces of Remington and Lapua brass that feed my .260 and my .260 AI. I have dies for .260 AI.

I have nothing for Creedmore. I also have no desire to add another caliber to the stable.

Back to the point. Is .005" enough material to properly center the chamber reamer without slop or excessive runout?

 

[bluedog69]

I would make it a 6.5 Beanmore!

 

[Mike D Texas]

My 260AI significantly outperforms my buddy's CM, at least in terms of velocity. He runs 2780'ish in a 24" barrel and I run 2980'ish in a 24" barrel. He is using H4350/143ELDX and I'm running H4350/144 LRHT. If I use RL26, I widen the gap another 50+ fps.

I get noticeably less drop and drift at distance over him, both shooting out to 1500 yards.

 

[CGohn]

It's actually more of an investment to go 6.5 Creedmore. I have hundreds of pieces of Remington and Lapua brass that feed my .260 and my .260 AI. I have dies for .260 AI.

I have nothing for Creedmore. I also have no desire to add another caliber to the stable.

Back to the point. Is .005" enough material to properly center the chamber reamer without slop or excessive runout?

I doubt that it will work without setting the barrel back. You are comparing the body diameter at the base and that makes it appear to possibly be an acceptable change. BUT, the body diameter of the 260AI shoulder junction compared to the body diameter of the 6.5cm at the shoulder junction is your problem area. The CM is .004" larger than the AI and at a point ~.170" back from the AI body/shoulder junction.

Hope this helps...

(Edited to correct the body/shoulder junction difference)

 

[FEENIX]

According to the chamber prints the 6.5 Creedmore is .4709" at the widest point on the case body. The .260 AI is .4714" at the widest point on the case body.

Question, is .005" enough material to keep a reamer centered when rechambering a mass production 6.5 barrel to a .260 AI?

Would setting it back a few threads increase the margin if the factory tolerances are too sloppy?

Back to the point. Is .005" enough material to properly center the chamber reamer without slop or excessive runout?

You are inducing an error, making it out of tolerance, so yes, it "can" have a negative effect. Most of us keep our runout at .002" and better. However, I say go for it if you think it is worth your time, money, and effort. We are saying to do it right from the start and go with .260 AI. Good luck!

 

[can1010]

your .200 line dia. isn't your problem the shoulder dia. is. creed .463, 260ai .460 you will have to remove a good portion of the Creedmoor chamber to clean up the shoulder with the smaller 260ai reamer. if you have enough shank left on the barrel to remove the threads and start over and the barrel is a quality barrel with low round count it might be worth it, high round count or factory barrel don't waste your time just save for a new barrel