6.5 Creedmoor with 1:7.5 twist...

[boisepaw]

Has anyone seen/shot a 6.5 Creedmoor with a 1:7.5 twist barrel that would handle a heavier bullet?

Where would I find a barrel with this twist rate? Anything stock or would it need to be a custom barrel?

 

[Supersubes]

Which twist are concerned with, 1:9 as in the title, or the 1:7.5 in your question?

 

[boisepaw]

Sorry...I was thinking about a different rifle. I changed it to 1:7.5 twist. That's what I'm wondering about. Specifically thinking about the 150 grain SMK bullet...

Thanks for catching that...

 

[Supersubes]

I can’t speak to the 150 as I’ve never shot it, but 1:7.5 is a very populist twist for the heaviest of heavies. Sierra recommends 7.5 twist for that bullet per their website.

 

[Steel head]

I’d play with a ballistic computer to see if the juice (150 and greater in 6.5 CM) is worth the squeeze at the distances your primarily shoot.

BC doesn’t mean squat if you don’t have the speeds to utilize it.

 

[6brshooter]

What steelhead said. Not too many people run over 123gr in a grendel, even with higher bc bullets available. While some of that is due to mag length, it doesn't have the ass to push it.

If you do plan on 150smk, might look into a shorter freebore so rds fit in ai mags. If I'm remembering correctly, alot of that bullets length is from ogive to tip, very similar to 110smk 6mm. I run a 147eldm in a 20" 6.5creed, I get 2730 with h4350 and 2690 with rl16

 

[stello1001]

You'll be fine with that twist, order it and run it...

 

[hereinaz]

I’d play with a ballistic computer to see if the juice (150 and greater in 6.5 CM) is worth the squeeze at the distances your primarily shoot.

BC doesn’t mean squat if you don’t have the speeds to utilize it.

This is solid advice to consider. For that reason, you won't find many factory 6.5 creed in 7.5 twist. You will have to go custom, most likely. What is your rifle and expected distance to shoot? You really have to be shooting really far to get to where a 150 with higher BC takes over the higher velocity "low" BC bullets.

I play with the twist rate calculator, but more than that look at dope charts for the bullets. The less powder capacity, the smaller the bullet. I can't see myself using anything but a 130-140 in a 6.5 creedmoor. I would absolutely run the 150+ in a PRC.

 

[BadAccountant]

There are a number of prefits with a 1:7.5 twist, and barrel makers will make you a barrel with just about any twist rate you can want.

However, unless you're planning on feeding it a steady diet of 150 SMKs you likely don't need it and most guys don't like the reduced velocity anyway due to powder displacement. Now a 260 AI shooting a 150 SMK on the other hand...

 

[White Mamba]

I run 147 elds in a 16" 6.5 creed with 7.5 twist and they shoot great

 

[Kryan]

Anyone do any further update on this? Was just reading on some local hunting boards discussions if the 6.5CM is appropriate for Elk? The na sayers say, bullets aren’t heavy enough. Proponents say it’s the velocity and shot placement. I’m not arguing who is right or wrong. But became curious what would happen if there was a 6.5 heavy bullet like a 180 or something.
heck maybe I should have started a new thread?

 

[Frank Green]

The 6.5CM would work just fine on Elk. Using like the 143ELDX would be a good pick or even the 140 Sierra SBT would be my first two choices.

You need a 7.5 twist min to handle the 150SMK. My twist rate calc comes in at a min. of 1-7.52 for twist.

Later, Frank
Bartlein Barrels

 

[Cascade Hemi]

The 6.5CM would work just fine on Elk. Using like the 143ELDX would be a good pick or even the 140 Sierra SBT would be my first two choices.

You need a 7.5 twist min to handle the 150SMK. My twist rate calc comes in at a min. of 1-7.52 for twist.

Later, Frank
Bartlein Barrels

At what velocity?

 

[Kryan]

For anyone else that wants to geek out a little, I found this.

https://apps.dtic.mil/sti/pdfs/ADA570469.pdf

From what I can tell both physical size and weight contribute to the best twist rate.
i still think it would be interesting to try, say a 168 or 175 out of a 1/8 std barrel

 

[Frank Green]

At what velocity?

I'm running 147, 150 and 153gr bullets at an honest 2700fps out of a 23" barrel.

135 and 140gr bullets at an honest 2800fps.

 

[jtackmann]

I have a hawk hill 26" 6.5cm 1:7.5 on my AXMC and it loves 144g and 156g berger. Either would easily take an elk out to 1000y imo.

 

[Baron23]

Has anyone seen/shot a 6.5 Creedmoor with a 1:7.5 twist barrel that would handle a heavier bullet?

Where would I find a barrel with this twist rate? Anything stock or would it need to be a custom barrel?

My 6.5 CM has a 7.5 twist Proof Research SS barrel. But I think any top shelf barrel manf would do any twist you spec'd, no?

 

[Ledzep]

47-48 Grains of RL-26 (if you can find it) works well in the 6.5 Creedmoor with 147-153gr bullets. Start at 45 and work your way up. I was getting an honest 2820-2850fps from a 24" barrel with 147's. 2780-2800 from a 22" barrel.