Twist rate question

[Nik H]

Hi all,

I have read an earlier thread regarding a 7.5 twist or 8 twist choice on a short barrel chambered for 6.5 Creedmoor.

I have a very similar question. I am looking to buy a new barrel for my AI AT and want a 26" length. I DO NOT reload and have no plans to. All of my previous barrels are 24" 8 twist. I primarily shoot PRIME 130 grain and Hornady 140 grain. I also occasionally shoot 147 grain Hornady. I may also try the new 150grain Sierra offerings.

My question is should I stick with an 8 twist or should I try a 7.5 twist? Would the faster twist compromise the performance of the 130 grain ammo? I do plan to run numbers in Coldbore but I also would like to hear from some of the more experienced shooters to see what they think.

Thanks in advance

 

[Supersubes]

I think most here would err on the faster side with those longer bullets, and I’d do the same. I don’t believe it will hurt your 130 performance one bit.

 

[Friday]

I shoot 150s out of my 1/8 twist creedmoor

 

[Rob01]

Up to 147s you will be fine with the 8 twist but some have had issues with the 150s at that twist rate so maybe go faster if you plan to use them a lot.

 

[AIAW]

Looks like a 1-8" versus 1-7.5" will take your Miller stability up from 1.4 to 1.6, respectively on a 147g ELD-M.

To each his own, but personally I don't run 147's any longer for anything under 1K yards (even then I prefer the 140g). The native BC benefit from the caliber is not as pronounced with the velocity that is lost running a heavier bullet. I've been seeing way better results with 140g ELD's. Under 1K I run 123g Scenars mostly that are absolutely screaming down range. All of this with a 26" 1-8" twist Bartlein.

 

[Friday]

Looks like a 1-8" versus 1-7.5" will take your Miller stability up from 1.4 to 1.6, respectively on a 147g ELD-M.

To each his own, but personally I don't run 147's any longer for anything under 1K yards (even then I prefer the 140g). The native BC benefit from the caliber is not as pronounced with the velocity that is lost running a heavier bullet. I've been seeing way better results with 140g ELD's. Under 1K I run 123g Scenars that are absolutely screaming down range. All of this with a 26" 1-8" twist Bartlein.

I also didn’t like the 147 grain bullets mostly 140s here. But I don’t mind the 150 Sierras ether but 140s I get the best results with

 

[AIAW]

I also didn’t like the 147 grain bullets mostly 140s here. But I don’t mind the 150 Sierras ether but 140s I get the best results with

Sweet. I'm not alone! Everyone raves about the 147's like they are God's gift to the 6.5. If anything I've learned over the years is that heavier isn't always better.

I've yet to try the Sierra 150's.

 

[Friday]

Yeah there were 3 of us that tried the 147s two of us have creedmoor and one has a 260AI we tried like hell to make them shoot and they just won’t shoot like the 140 grainers or 142 grainers

 

[Rob01]

I get the 147s at 2820fps from my 27" barrel and it's a very good long range round. Flatter and better in wind than my 140 ELDs at 2850fps. Not sure why anyone would say they like the 150 and not the 147 as ththe BC is very close and you will get similar velocities. If you like 140s then that's great but if going to 150 then the 147 is also worth a look especially in that it is made to stabilize in an 8 twist so no need for faster.

That said I have used the 140 weight since I started shooting the Creedmoor in early 2008 and still do. It's a very good weight for the round.

 

[Friday]

Well the 147s shoot way different out of my rifle than the 150s do I use N160 behind the 150 and it shoots pretty damn good I’ve tried reloader 16-17-19 H4350, N160,N550 behind the 147 and no luck.

 

[Rob01]

I understand the choice if accuracy differences were involved but some say then 147 is too heavy and then use a 150. Makes no sense to me.

How far off the lands were you?

 

[Friday]

Started 10k off and worked my way to 90k with no prevail

 

[Supersubes]

Weird, I’ve found the 147 to shoot in every barrel and carrridge I’ve tried. I jump them .030, and they just flat out work. I’ve also managed to buy a few thousand of them over the last year or so on sale for around 28 cents each, which is pretty slick. Admittedly, unless you get them to go reasonably fast, they end up being a wash for drop and drift compared to the 140. I use rl26 in the creed.

 

[Rob01]

Started 10k off and worked my way to 90k with no prevail

Hmm odd. I shoot them handloaded at .030" off and in the factory ammo they are about .090" off and both shoot great. I have only used H4350 with them. What charger you use?

 

[Nik H]

Thanks for all of the inputs. To really be honest, I get better results with the PRIME 130s than the Hornady 140s when shooting at distance. I know that sounds odd but the PRIME drops less. It may not be as good in the wind but it requires less holdover due to the faster MV.

If I were to categorize what I shoot by % it would be

PRIME 130s - 45%
Hornady 140 ELDM - 40%
Hornady 147 ELDM - 15%

I doubt that I will alter that mix too much. Most of my shooting is 600 yards and I do a lot of shooting for group size to keep it challenging at the short distances so precision is more important to me than when I shoot steel at longer ranges. Based on this, I probably should stick to an 8 twist? I do like trying new things, especially since both of the 8 twist barrels I have still have a good life in them, but wanted to try something different.

Would that change any of your opinions?