I'm going to have a 700 SPS .300 WM rebarreled to .270 Weatherby Mag. I'm intending to shoot the longer bullets (150g LRAB, 145g ELD-X, etc.) the shortest bullet I would opt for is the 140g NAB. Standard twist is 1:10. I've read where the ELD-X recommends 1:10 or faster. Should I spin the barrel a little faster say 1:9.5 or 1:9?

If it were mine I'd be doing a 9 twist. I'd probably go 8 just to make sure I got all I could out of the 150 ABLR, but honestly it is shooting fine in my 10 twist 270 Winchester and 10 twist 270 WSM. I think you'll have a firebreather when you are done...

I have come to the conclusion 1/8 twist is the answer for everything from .22 to .284. no downside and bullets are getting longer.

Mine has a 1 in 9. I shoot the 140 Accubonds, I haven’t tried any heavier bullets. It shoots the 140’s so well, it’s hard to change.

No downsides in going with a faster twist, I would look at a 1 in 9 minimum but probably would go with a 1 in 8. My 270 Win is a 1 in 9 and does well, had I had the option at the time to go 8 or 8.5 I would have done it. Still want to do a fast twist 270 Wby one day...........

Whenever I re-barrel my 270 WSM I will go with a 1 in 7 or 1-8 because of more new longer bullets. Not sure if the Weatherbys speed will make up for a slower twist or not with the 170s and other VLDs. Hill Country Rifles thought the 1-8 was on the fast side for the 6.5x300 Weatherby and build theirs with 1 in 9 twists. At least for them it has proved more accurate. The only light weights I will shoot are the mono metals so the higher RPM could increase the leathality or so some believe.

Which barrel makers twist 270 cal faster than 1-9? Most are 1-10 only.

McGowen gives you a choice for their custom barrels. I'm thinking 26" Remington Magnum contour (to minimize stock inletting issues), 1:9 twist, with maybe some flutes, still undecided about that yet.

Krieger will twist them however you like.

Me too Gerry!

Benchmark does a 1 in 8.5. My 1 in 9 barrel is a Benchmark, at the time I bought it they didn't offer the faster twist. I would buy that 8.5 in a heart beat if a new barrel is needed. I believe Pac Nor offers a 1 in 8.

Been wanting one for years and even have dies already, might as well make it a fast twist.

Looking forward to seeing how yours turns out magshooter1

^^^ This. ^^^

There is just all upside to 8” twist. No cons at all. And with those long bullets, the upside is magnified.

No doubt in my mind that if I built another .270 Roy that it’d have an 8” twist.

BTW, EXCELLENT cartridge choice. As far as I’m m concerned, it is the absolute top of the food chain when range/killing power/recoil are all given equal weight.

I had a 270 WBY built with 1-10 Krieger 4 grove Sendero profile on a 700 SS action, HS Precision stock. It likes the 140 Accubonds and the Barnes 130 TTSX. I went this route instead of a 26 Nosler do to the fact Brass was easier to come by and the Performance was close enough for me. If I wanted to shoot heavier bullets I would have went with a 7mm WBY or STW.

TEXMAG

You might want to have an M-16 extractor installed in your bolt while your doing the build. The extractor on mine didn't last 20 rounds on a new SS 700 action. I am having a PT&G bolt fitted in the action now with a M-16 extractor. Was going to do it when I had the rifle built, but the original bolt I purchased from PT&G had an issue so I had to wait awhile get the right bolt from them. The customer service was great, but I had to ship the original bolt back and wait for them to send another. The second bolt wasn't exactly what I ordered either. I wanted the bolt with small firing pin hole in the bolt face, but the one I received had the standard firing pin hole. Wasn't worth the trouble to send it back again. Anyway good luck on your build.

TEXMAG

have a 270-300 win mag that was built 15 years ago.it has a 10 twist broughton barrel 3 contour.the only bullets I shoot out of it are 130 gr barnes and 140 noslers.i got lucky with this barrel.i believe it is that one time hummer as it is beyond belief accuracy wise.when it starts opening up I will be doing a 1-9 or 1-8 for todays excellent longer bullets.hopefully with a mullerworks if he makes that twist.good hunting