Is 1 in 9 enough to stabilize 6.5C 140gr A-Max??

[CUSTOM1911FAN]

Howdy All,

Well, after much hemmin and hawin and reading some excellent threads, I have chosen 6.5 Creedmoor for my next long range build. Primarily, I want it in a bolt gun, but I would also like to buy a 6.5C barrel for my slick sided LMT MWS that should arrive next month. Hence the question, will the 1 in 9 twist on the 20" stainless LMT barrel be fast enough to stabilize 140 grain A-max ammo? Everything I've read says that I need a 1 in 8 twist barrel to stabilize the 6.5C. Thoughts?

Is anybody running this LMT 6.5 setup, already? Results?

Thanks

 

[Rob01]

Re: Is 1 in 9 enough to stabilize 6.5C 140gr A-Max??

Most go 8 or 8.5. I think 9 would be pushing it in a 20" gas gun. You can always run the 120/123grn bullets if the 140s don't work for you.

 

[CUSTOM1911FAN]

Re: Is 1 in 9 enough to stabilize 6.5C 140gr A-Max??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rob01</div><div class="ubbcode-body">Most go 8 or 8.5. I think 9 would be pushing it in a 20" gas gun. You can always run the 120/123grn bullets if the 140s don't work for you.</div></div>

Roger that, Rob.

Huh, why the frack would LMT choose the 1 in 9, over the 1 in 8? (rhetorical question)

Maybe the 140grain loading wasn't around at the time the barrel was developed????

 

[Rob01]

Re: Is 1 in 9 enough to stabilize 6.5C 140gr A-Max??

140s were there from the start. Maybe they figured more people would use the lighter bullets.

Ask them if they are using 9 twist. Could be a misprint or old info not updated. They could be getting 140s to stabilize with the 9 but I would be concerned.

 

[tylerw02]

Re: Is 1 in 9 enough to stabilize 6.5C 140gr A-Max??

I had a 20" .260 Rem 1:9" bolt gun. It would stabilize 140s as in they didn't keyhole at 100 yards, but accuracy was much, much better with 100-123 gr projectiles. Meanwhile, I've had 1:8 and 1:8.5" that do great with 140/142s. I'd think a large part will have to do with the velocity when you're on the fringe. I'd probably try one box and see if it works, but wouldn't hold my breath.

 

[Rob01]

Re: Is 1 in 9 enough to stabilize 6.5C 140gr A-Max??

Exactly. With a 20" bolt gun you could push them faster but with a gas gun you can't run the pressure up to get the 140s running fast.

 

[fcsurvivor]

Re: Is 1 in 9 enough to stabilize 6.5C 140gr A-Max??

I have a .260 bolt guin with a 1:8 and it shoots the 140 VLD's at 2850 like no other. I tried some Federal factory .260's loaded with the 120gr BT and they were all over the place. I don't care much though because all I shoot are the 139 Lapuas and the 140 VLD's and A-Max. I would think you would want a 1:8 twist though for the 140's.

 

[m1ajunkie]

Re: Is 1 in 9 enough to stabilize 6.5C 140gr A-Max??

Another member here on the hide pointed me in the direction of a 1/8" 6.5CM barrel from LMT.

Link:
King optic usa

Like you I was looking for a 1/8" 6.5 caliber barrel and after months of waiting I bought one from king optic usa. Hope to have it here tomorrow and maybe I'll get a chance to run it before Thanksgiving to let you know how it goes.

 

[CUSTOM1911FAN]

Re: Is 1 in 9 enough to stabilize 6.5C 140gr A-Max??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: m1ajunkie</div><div class="ubbcode-body">Another member here on the hide pointed me in the direction of a 1/8" 6.5CM barrel from LMT.

Link:
King optic usa

Like you I was looking for a 1/8" 6.5 caliber barrel and after months of waiting I bought one from king optic usa. Hope to have it here tomorrow and maybe I'll get a chance to run it before Thanksgiving to let you know how it goes. </div></div>

Cool, thanks M1a. I looked it up, but of course they're out of stock. I put my name on the list to be notified when the barrel is back in stock.

But, still, I am confused by this whole situation. If that is, indeed, an LMT 1-8 barrel, then why is it not listed in the catalog? Why just list the 1-9? Did you ever get an answer on that? I emailed LMT asking that, but who knows if and when they'll reply. I was hoping someone on this forum would have a line into LMT to ask for us.

Oh well, I'll cross my fingers and hope I get that 1-8 before Christmas.

 

[CUSTOM1911FAN]

Re: Is 1 in 9 enough to stabilize 6.5C 140gr A-Max??

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: CUSTOM1911FAN</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: m1ajunkie</div><div class="ubbcode-body">Another member here on the hide pointed me in the direction of a 1/8" 6.5CM barrel from LMT.

Link:
King optic usa

Like you I was looking for a 1/8" 6.5 caliber barrel and after months of waiting I bought one from king optic usa. Hope to have it here tomorrow and maybe I'll get a chance to run it before Thanksgiving to let you know how it goes. </div></div>

Cool, thanks M1a. I looked it up, but of course they're out of stock. I put my name on the list to be notified when the barrel is back in stock.

But, still, I am confused by this whole situation. If that is, indeed, an LMT 1-8 barrel, then why is it not listed in the catalog? Why just list the 1-9? Did you ever get an answer on that? I emailed LMT asking that, but who knows if and when they'll reply. I was hoping someone on this forum would have a line into LMT to ask for us.

Oh well, I'll cross my fingers and hope I get that 1-8 before Christmas. </div></div>

epaultmbt solved the mystery in the next thread over:

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: epaultmbt</div><div class="ubbcode-body">I spoke to LMT today and confirmed that all current barrels have a 1-9 twist and there is no plan to do a future 1-8. I was then told that the early run of the 6.5 barrels were 1-8 and some may still be found instock with distributors.

Does anyone know where I can find one of these barrels? </div></div>

FML. Why did they choose a 1-9??? Oh well, good thing my best friend is a machinist/gunsmith. Let's see if we can reverse engineer the 308 barrel and figure out how to make one to work in the MWS. He's built precision AR barrels and rifles from scratch, hopefully he can figure it out.

Any takers, if he does figure it out??

Thanks for all your input and knowledge, btw. In 5 years of following boards, I think the SH community is the most professional and helpful of all of 'em.

 

[VKC]

Re: Is 1 in 9 enough to stabilize 6.5C 140gr A-Max??

1 in 8 for 140grs would be preferred.

 

[MontanaHick]

Re: Is 1 in 9 enough to stabilize 6.5C 140gr A-Max??

My stability calculator program tells me that no, it won't be stable at 1:9 unless you can exceed 3400 FPS (no clue about Creedmore velocities), and then it's only marginally stable. I'd say skip it and do something else with that barrel. The bottom line is you need a 1:8 for the 140s.