Twist for a 6.5 Barrel

[35 Whelen]

If a guy was going to buy a new PacNor barrel to build a 6.5x06 up and wanted to explicitly shoot Noslers new 142gr LR bullets thru it , what twist in the barrel is going to be optimum for that bullet weight to make sure it stabilizes it correctly ???? 8)

 

[IdahoCTD]

I would shoot a minimum of a 8.5" twist and a 8 twist wouldn't hurt you. I have 6.5mm's from 6.5x47's to 6.5-300wm's with 8 and 8.5 twist and they all shoot well with 140's. I have a 6.5-300wm that has a 9 twist and won't shoot 140's to save it's life. 123's going in 3/8" but 140's are 1+".

 

[jimbires]

Brian Litz shows you want an 8 twist to get the full BC from the 129 gr ABLR bullets . I'd say for the heavier bullet you would want at least 8 twist, or maybe even go to a 7.5 twist .

http://www.longrangehunting.com/forums/ ... ts-137554/

 

[35 Whelen]

Sounds like an 8 may be the sweet spot................. thanks for that info! Toying with the idea of building one up, god knows I need another rifle! lol... ah well its cheaper than drinking!

CUSTOM ORDER DEPOSIT
Pac-Nor Custom Barrel
Base Price $305
Caliber:6.5mm (.264")
Chamber:6.5-06
Stainless Steel
Grade: Standard-Match
Twist: 5 groove/8" twist
Contour: undefined
Finished Length: 26
Crown: No Crown
Finish: Polished
Fluting: no fluting
Type: Prefit Barrel
Action: Remington
Total Cost: $430.00
Deposit Due with Order: $215

 

[gerry]

1 in 8 is what I would do. My old 264 WM, my wife's 6.5x55 and my 260 Remington are all 1 in 8's and shoot well. I have had a couple of 1 in 9 twist 260's and they didn't always shoot even the standard 140's very well, something like the 142 gr ABLR would have definitely not shot well.

Berger's twist calculator may be of some help to you.

http://www.bergerbullets.com/twist-rate-calculator/

 

[35 Whelen]

Thanks Gerry,
That sounds good enough for me! What do you think of a 6.5/06??? Be interesting to hear your thoughts?? Have you shot the new 142LR ???? The BC on that bullet flat out amazes me! Maybe Mike will chime in as well ???
Earle


Stability Analysis from the Berger calculator;
Your bullet is STABLE.
Your bullet is flying with full stability. You can expect good groups and your BC is optimized.
SG = 1.60Bullet BC (G1): 0.720Your bullet is achieving its max BC.Your twist rate is optimized for this bullet.

 

[gerry]

While we love our 260 and 6.5x55 the 6.5-06 will do anything they will and more. The 6.5-06 really isn't much slower than a 264 WM. I can't imagine you would ever be disappointed in the cartridge, if that's the way you want to go it is an excellent cartridge. I haven't yet shot the 142 gr ABLR but have worked with the 129's and found them accurate. Over time I have come to prefer bullets around 130 gr in the 260 Rem since you can move them a fair bit faster than 140's but a 6.5-05 will easily more the heavy 140's at an excellent speed.

 

[35 Whelen]

That all sounds like rock solid advice Gerry , thanks for sharing that. Was speaking to a friend today that is an old 25/06 guy that screwed a 6.5 barrel on a few years ago after he burned out his barrel , he was quoting figures around 3K with 139gr bullets and wants to shoot the new Nosler but is afraid his 9 twist wont stabilize them .......................
e
My Dad hunted with a 6.5x55 for years and we always thought it was a real sleeper cartridge way back in the 60s , killed big deer like they were struck with a bolt of lightning. I took it to New Zealand and found it worked just as good on Red Stags!

 

[gerry]

Punching the 142 gr ABLR into Breger's calculator says it will be marginally stable in a 1 in 9 and fully stable in a 1 in 8. They show the 129's also being marginally stable in a 1 in 9 but fully stable in a 1 in 8.5. Your friend might do well with the 129's and would be worth a try.

 

[Dwh7271]

You received good advice. An 8 twist is the way to go.
I run the 140 AB and 140 BT in mine a hair under 3000. I'm working a load with a new powder that takes it a little over 3000. I'll post it up if it tightens up a touch.
The 26 is also a good length.
Don't overlook the 130s though. Some pretty slick bullets out there and 3100 is fairly easy with a 130. Unless you're going out past 600 or so I doubt you'll notice the difference. Way out there the 140 or 142 does have an edge.
I also run one in the Ackleyed version, I like the 6.5-06 cartridge :grin:

 

[Wyo7200]

Posted this for the creedmoor, but it's essentially the same for .260's

Got tired of bouncing from site to site plugging in bullet data so I made my own calculator based off the equations found on accurate shooter and the such.

 

[gerry]

You received good advice. An 8 twist is the way to go.
I run the 140 AB and 140 BT in mine a hair under 3000. I'm working a load with a new powder that takes it a little over 3000. I'll post it up if it tightens up a touch.
The 26 is also a good length.
Don't overlook the 130s though. Some pretty slick bullets out there and 3100 is fairly easy with a 130. Unless you're going out past 600 or so I doubt you'll notice the difference. Way out there the 140 or 142 does have an edge.
I also run one in the Ackleyed version, I like the 6.5-06 cartridge :grin:

Out of curiosity what do you think a 24" barreled 6.5-06 would do with 140's? 2900 or maybe 2950 fps? I know Earle is thinking 26" but I always have wondered what a 24 would do.

 

[muleman]

1 in 8 will work just fine. I run a 1 in 8 on my Creedmoor and it stabilizes the 140s just fine. Look at Benchmark barrels; you can get the same or better barrel for about $295 from their distributor.

Scott

 

[35 Whelen]

Thanks Scott,
That's interesting they have SS barrels in the Sendero profile,with 8 twist /26" for $295! Nice
Great info........

 

[RiverRider]

35, have you considered going with an AI chamber?

 

[Dwh7271]

Out of curiosity what do you think a 24" barreled 6.5-06 would do with 140's? 2900 or maybe 2950 fps? I know Earle is thinking 26" but I always have wondered what a 24 would do.

I would think in the range of 2875-2925. Depends on powder and barrel. Still playing with some of the newer powders in mine and one seems so far to give a bit more speed. I'll stick up the results once I finish.

 

[35 Whelen]

RR.
No have not , but I do realize the benefits of the AI reamer! However I am just crunching numbers right now to see if any of this makes sense.........
My problem is I am toooo practical, and have to analyze things tooo much. LOL
I am thinking of selling my little .243 Ultralight Ruger and replacing it with a 6.5 of some flavor, looked at the Ruger Americans in 6.5 Creedmore and they are a cute little gun, but not sure I am happy with the powder capacity of that case??? I read all the hype but don't see how that is anything the old Swede isn't????
I was just gawking at a Tikka T3 Stainless, Black Matt; on a close out from a distributor we buy from, that has the 8 twist barrel already on it,[to shoot these long bullets, Bergers and ABLRs] and being a dealer I can buy a T3 Stainless in 6.5x55; for about a 100 bucks more than a rebarrel of an existing gun ????. So now need to reassess my thinking as to how much better a 6.5x06 is with the bigger case and IF I really need that advantage, to do what I am wanting to do?????????
So my common sense is telling me to just buy the x55 with the 8 twist and have fun with it ................... but of course the wildcard side still says but a 6.5x06 would be waaaaaay
cool. :mrgreen:

 

[Dwh7271]

There's a lot to like about the 6.5-55. I think scotty's working up loads for one. Should be interesting to see what he gets out of it.
I don't own a Tikka but keep hearing good things about them.

Back to the 6.5-06, an earlier post mentioned the Ackley version. Obviously you bring in fireforming with that but the difference in my two is about 120 fps if that helps? I'm also not really hotrodding the AI at that.

 

[35 Whelen]

Dwh,
What do you think top vel with some of these new powders is going to be out of a Tikka in 6.5x55 ???[22.5" barrel]
Or better way of saying that would be how much extra vel would you say realistically from the 6.5x06??[24" barrel]
Say 129gr or 139grs????
e

 

[Dwh7271]

I'd think the regular 6.5-06 is going to be right at 3000 w the heavies and 3050-3100 or so w the 120-130s.my 6.5-06 is running 130s at 3060, the AI about the same with 140s.
The Swede probably 100 fps or so slower.