Twist rate for new build

[cowboybart]

I am new here and new to Grendels. I am seasoned on the 6.5 bore.
I am looking for info on the twist rate of the 6.5 Grendel. I read in several posts that a 1:9" is the way to go, but others stated a 7.75 twist works for them. I can't decide on a 20" or a 16" so I thought an 18" would be the answer. I haven't bought factory ammo (except 7.62x39) in 20+ years. I doubt I will buy it for this project. I have a slug of 139 and 140gr bullets on hand. Will these fit in the magazine when seated to the cannelure?? Will they stabilize in the 9" twist barrel?? These are hunting bullets - not VLD's, bullet length is 1.25", the cannelure is .425" from the base.
JT distributing seems to be highly recomended, but don't offer an 18" with a 8" twist. Are there any others that are recomended that may offer it?

[RangerRick]

Hi CB, welcome to the horde! I'll take these one at a time:

--I am looking for info on the twist rate of the 6.5 Grendel. I read in several posts that a 1:9" is the way to go, but others stated a 7.75 twist works for them.
--I have a slug of 139 and 140gr bullets on hand. Will these fit in the magazine when seated to the cannelure?? Will they stabilize in the 9" twist barrel??

I put these together because they are related. In general the Grendel gets best energies out of bullets in the 120-123 grain class. Recently some of us have had good luck with 129-130 grain bullets with CFE 223 powder (search for the threads if you are interested).

You can shoot 139-140 grain bullets but you won't get great velocities out of them. I've only loaded a few bullets with cannelures (or bands in the case of the Barnes solids), but there wasn't room in the case to load them to the cannelure or cover all the bands. You don't really need to crimp anyway with good neck tension.

Other guys can tell you more about the twist needed, but the heavier, longer bullets require more twist. I shoot the 130 grains out of a 20 inch 1:8.5 barrel with no problem. Range is an issue here too. If you want to go for 1000 yards you might need more twist with the heavier bullets.

Usually the bullets over 123 grains have to be seated so deep to fit in the mag that it restricts powder space in the case.

-- I can't decide on a 20" or a 16" so I thought an 18" would be the answer.

You generally lose about 25-30 feet per second, per inch of shorter barrel. The loads on the Alexander Arms web site (http://alexanderarms.com/images/pdfs..._reloading.pdf) are from 24 inch barrels, so you can extrapolate from there to get the velocities you need.

--I haven't bought factory ammo (except 7.62x39) in 20+ years. I doubt I will buy it for this project.

No need with good dies. Although cheap steel case ammo is coming "real soon now". That's a running joke here because we've been hearing it for 3 or 4 years. It looks like it might actually be true this time though, probably late 2012 or early 2013.

--JT distributing seems to be highly recomended, but don't offer an 18" with a 8" twist. Are there any others that are recomended that may offer it?

I don't know of any out of the box, but lots of gun smiths can cut one down for you. To save $$$ though I'd go for the 16 or 20. The 16 will be more compact/lighter for hunting and a lot of guys here hunt with them out to 300 yards. You'll get about 50-60 fps less than the 18, if that works for you.


RR

[bwaites]

Welcome!

Twist rates have been discussed at length, and Bill Alexander has even answered this question, so some searching will turn up some good information for you!

[VASCAR2]

Midway USA has an 18" AR Stoner 6.5 G/264LBC 1 in 8 twist SS barrel in stock with bolt for $299. These barrels get good reviews and are basically rack grade button rifled barrels. These are good barrels if your hunting and not a serious long range shooter. Most avid long range shooters prefer cut rifle barrels longer than 18". I already have a 16" 6.5 Grendel and don't need an 18" barrel but these are some of the few barrels in stock and keep tempting me.

[mongoosesnipe]

I decided to fallow the advice of the techs at satern and go with a 1in8.75 I will let you know how it works out in a few months

[cowboybart]

I will be using this for hunting so button rifle barrel will work. I usually don't hesitate on a 400 yd shot at an antelope, if conditions are right.
I did read on here about subsonic 160gr loads - now we are talkin'!!!
Being able to hunt antelope/deer with 130gr and shooting subsonic with the same rifle - that's the direction I will go.