Twist Rate

[Big Dog]

As I continue my research on what to buy, I’m faced with a question. What’s the best (right?) twist rate? I see mostly 1:8 or 1:9 but AA has a 1:7.5 on an 18 inch barrel.

My 5.56 experience tells me a tighter twist throws heavier bullets more accurately. So, I presume the same holds true for 6.5 Grendel.

Most of my use will be hunting Eastern whitetails and putting holes in paper/ringing steel out to 500-600 meters. For that, it seems a 1:9 twist, firing with 100-123 grain bullets should be more than adequate. However, I may take it out west for Mulies and elk. Are 123gr rounds enough for that? If so, I likely don’t need to worry about it. But if I’ll need 160gr rounds, I reckon I’d probably need a tighter twist. Am I crazy? Or am I over thinking the whole thing?

[A5BLASTER]

8 twist will cover everything from 85 to 130 grain.

I have the 16 inch AA barrel with the 7.5 twist and shooting the same ammo I can't tell the different in groups between it and my 8 twist 20 inch group buy barrel.

8 twist is the standard twist for almost all barrel suppliers.

Although I wouldn't turn down a 20 to 24 inch barrel if it had 7.5 twist.

8 twist with 120 to 130 grain bullets preferably all copper bullet and 300 are less yards should do for elk.

Mark Larue killed a big bull at 400 yards with a complete pass through If o remover correctly and he used a 120 tsx bullet from I think a 18 or 20 inch barrel.

Google search ar15.com for the post it's still on there somewhere's.

If I was going after elk I would run the 127 lrx, 129 ablr or 130 Berger hunting or 130 game changer bullet from my 20 inch grendel and set my max range at 300 yards.

For deer and hogs 400 or less the 123 eld-m, old amax, sst will do just fine.

Or choose one of the higher weight pills and develop a good elk load and use it on everything from 400 yards and closer.

Hope this helps sir.

[centerfire]

7.5 to 8. Personally I think bullets that would need 7.5 or faster aren't well suited to the Grendel cartridge.

[Big Dog]

That’s exactly what I wanted to know A5BLASTER. In case I wasn’t clear, my max range for game would not exceed 400 yards. I can’t see that far no matter how good the optic is. 😂

So I guess it’s 1:8 - unless I get the 18” AA with the 1:7.5 just to make you jealous... 😉

[A5BLASTER]

That’s exactly what I wanted to know A5BLASTER. In case I wasn’t clear, my max range for game would not exceed 400 yards. I can’t see that far no matter how good the optic is. ��

So I guess it’s 1:8 - unless I get the 18” AA with the 1:7.5 just to make you jealous... ��

Sounds good lol.

But my rebarrel for my custom bolt action will have a 26 inch 7.5 twist one day.

[Sticks]

This is what is nice about the Grendel and a couple other recent 6.5 caliber sammi spec cartridges - the first and only ones to have a 1:8 twist rate, others are much slower. Thus we can utilize the heavier and high BC bullets. The most recent addition to the 6.5 lineup is the PRC, which is also speced for the 1:8 twist running up to 147gr pills.

[Bobke]

Not to confuse the conversation, but have both 20-24” Satern cut rifled barrels with 1:8.75 twist and they both shoot 129 ABLR’s into very small holes. Short throated with blunter ogives, but shoot, nonetheless. Just as good as 8 twist Bartlein, JP and Lilja barrels. Which might suggest quality of chamber and barrel have more to do with results than twist alone.

[kmon]

When in doubt about twist rates for a bullet check out the Twist rate calculator on Bergers site. My 2 Grendels have 1:8 for a 24 inch barrel AR and 8.4 for the Bolt action with an Obermeyer barrel. Both do well with up to 103gr Berger Hybrids and 129gr ABLR bullets.

For other bullets than Berger you can put in the length weight and velocity to use their calculator

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

[Big Dog]

That’s a great calculator, kmon. Thanks.

I’m now convinced a 1:8 twist in a 18”-20” barrel will most likely be the best option for my purposes initially.

Next payday will almost certainly see an order - presuming the upper is in stock at PSA. If I like it as much as I think I will (and as much as the rest of the horde does), my next step will probably be to save up and assemble one from scratch.