Home Forums Hunting & Shooting Long Range Hunting Barrel twist for 270 Weatherby

Hi I'm about to send my vintage Mark V in 270 Weatherby to Hart barrels. I plan to keep the same barrel length (26") and contour. I was thinking about a 1 in 8" twist but am thinking maybe I should go 1 in 7". I plan to shoot heavy for caliber bullets 165g, 175g and maybe the Woodleigh 180g. What do you think?

Thanks,

I’d do the 1-7 myself.

That should be a fun rifle when it’s done!

Thanks!

1:7, projectile R&D is unlikely to go the way of requiring less twist any time soon.

1-7 and might as well step up to a 28 inch barrel while you're at it. Cheap and easy to cut it down later if you really find yourself fighting the length.

Thanks but this is a hunting rifle, sometimes I hunt the black timber for elk. 26" is as long as I'm comfortable. Will definitely go with the 1 in 7" twist though

I don't think Hart does a 7 twist in .270. 8 twist is becoming the new standard in .270 and that is what I'd go, but 7 would cover possible developments in bullet b.c. if you can get a 7 twist from a barrel maker that you like. In your situation for woods hunting, I'd consider a 25 inch barrel.

Keep in mind the std 270 Wby has .378” of freebore in their chamber design. All Wby ammo is designed for that far of a jump operating at 62,500 psi. When loading fast twist, long and heavy you will need to deviate from that freebore distance and need to be aware of 270 Wby loads that maintain 62,500 psi but now possibly leave the freebore at 0.050” or less, which may increase pressure considerably if not accounted for.

You need to look at what your hunting needs are and discuss with Hart as to std 270 Weatherby chamber or possibly 270 Wby without design of .378” of freebore to specifically shoot fast twist/heavy bullet design having a change in COAL outside the 270 Wby specs. Obviously if not cut to std Wby chamber, no Wby ammo should be used due to higher pressures in Wby ammo and chamber being out of spec.

If desire to shoot 130,140,150 Wby loads and std load data then a 1-10 or 1-9 would be fine with a std 270 Wby chamber. If shooting 160-180 gr on a 1-8 there are better platforms than a 270 Wby chamber that do not use excessive freebore in chamber design such as a 7mm PRC. For general hunting at 500 yards I’d keep the barrel you have unless it’s shot out.

You just need to be aware of some of the COAL work arounds and pressure when running various COAL in a std Wby chamber with that much freebore in the design, which allows another 1.5K-2.5K psi in std loadings over other chambers like the 7mm Rem Mag and some of the other belted magnum designs.

Remember the 270 Wby is Roy’s first cartridge out of the gate in 1944 or so. Not exactly new or cutting edge. However the original design intent offers quite a bit of horsepower without worrying about 170 and 180 grain loads out at 700-800 yards. Only one man’s opinion.

I think it’ll be wicked. Keep the throat tight and it should be a blaster.

I recently rebarreled my Wby MK V with an original contour 26" in a 8 1/2" twist and it seems to work fine with bullets up to 160 grs and still yields excellent accuracy on the lighter 130 gr loads. I think I would be happy with the 8" twist.

7T makes a lot of sense.