Barrel twist rate

[Dt219]

What barrel twist is most guys running on here that is shooting THE LIGHTER BULLETS ? I figure most is 1:9 or 1:8. Post below pretty please

[Red*Lion]

I believe that you are correct.

[VASCAR2]

[A5BLASTER]

Only 8twist I have is the barrel on my cz 527, when it's done it will be replaced by a 7.5 twist.

All my short barrels are 7.5 twist. I have to agree with Bill's design work. 7.5 twist just flat out works.

[lazyengineer]

Pretty much what the above say. If short, go 1/8 or even faster. If 20", my own experience was that 1/8 is too fast for optimal accuracy. Bill Alexander said the same as well, and suggested running 1/9, which eventually I did, and just like that, I'm now shooting 1 MOA.

So... Donno, I guess if you're going
pistol length (which I don't really advise that road in 2021), then 1/7.5 or such.
If 16-18", 1/8.
If 18-20"+ 1/9. At least, that's what I've seen and read.

If 14.5 pin and weld... I guess 1/8 is what I'd do personally based on the several barrels I've gone through, and just avoid the 129+ weight loads.

[Harpoon1]

https://youtu.be/VA7H9tDfm_c

[Dt219]

[VASCAR2]

https://bergerbullets.com/twist-rate-calculator/

Here is a post from Bill Alexander on different twist with the 6.5 Grendel.

https://www.65grendel.com/forum/showthread.php?1854-Best-twist-rate&p=20344&viewfull=1#post20344

[VASCAR2]

[kmon]

I have no problem running 130gr Bergers from a 22 inch 1:8.4 Obermeyer barrel on a CZ527. Easily shoots half MOA to 300 yards and a bit under MOA at 600 is I am sure me, I just do not shoot past 300 very often. Velocity 2250 to 2550 in load workup no issues with stability.

[tdbru]

Dt219,
for what it's worth, i tend to agree a bit with VASCAR2. a QUALITY barrel will group well. 1-8 or 1-9 probably very little difference. with a bargain basement barrel, roll the dice. they may group well, but more often than not they disappoint. So.. before you go chasing barrel twist rate, consider a higher quality barrel too. i have a 260 Rem match rifle with a heavy SS 1-8 Krieger and it will outshoot my ability with any 6.5 bullet i've stuck in it so far. So if you want to go 1-9 and have a 20" or longer tube, it looks like Bill A. thinks that's a perfect match. if you're really chasing that 5 shot bug hole group, you would likely be closer to that goal using a quality match barrel first (brux, bartlein, shilen, krieger, etc.) and worry about the twist rate as a secondary issue. just my opinion so treat my response as just that. my opinion.
-tdbru

[Dt219]

[LR1955]

Dt:

I would go with the standard 1/8 twist. It will work well with all weights and lengths of bullets while a 1/9 will work well with the lighter and shorter bullets but probably not as well with heavier bullets. Not sure the cut off weight and length but in the 120 to 130 grain arena. There is a reason shooters went from a 1/9 to a 1/8 twist. It was to shoot the 130 and 140's but it is always better to over stabilize a bullet than under stabilize so the 8 turn twist became the standard. I also recall Alexander saying that with the short barrel carbines a 7 1/2 twist seemed to be better for function but don't quote me.

LR55

[ricsmall]

What barrel length are you planning to run?

[VASCAR2]