Fast twist 270 Wby?

[javman]

Been contemplating a fast twist 270 Wby with the 165gr LRAB bullet throated enough to make use of full case capacity ever since they announced the new 6.8 Western. My question is how much more velocity will one gain with this approach? Thanks in advance.

 

[FEENIX]

Been contemplating a fast twist 270 Wby with the 165gr LRAB bullet throated enough to make use of full case capacity ever since they announced the new 6.8 Western. My question is how much more velocity will one gain with this approach? Thanks in advance.

The barrel twist rate is for bullet stabilization, not velocity.

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

 

[scope-eye]

I have both a 270 WBY and a 270 WSM, and on the heavier bullets there is at least a 200fps advantage for the WBY. I can get 80gr of powder in the WBY and 70gr in a WSM and the 6.8 will be 4gr less than the WSM so 14gr difference I would say an easy 300fps drop for the 6.8 over the WBY with the 165gr bullets. Not to mention you can load the WBY a lot Hotter than a WSM style case.

Dean

 

[FEENIX]

I have both a 270 WBY and a 270 WSM, and on the heavier bullets there is at least a 200fps advantage for the WBY. I can get 80gr of powder in the WBY and 70gr in a WSM and the 6.8 will be 4gr less than the WSM so 14gr difference I would say an easy 300fps drop for the 6.8 over the WBY with the 165gr bullets. Not to mention you can load the WBY a lot Hotter than a WSM style case.

Dean

Unless I misconstrued the OP, he is asking if a faster barrel twist rate increases velocity. An increase in barrel length is another story.

 

[scope-eye]

I miss read it, no Velocity or FPS gain it just allow you to run the heavier bullets and stabilize them.
But what I wrote priour still applise.

Dean

 

[javman]

Yes wanting to see how the Wby with the 165s would perform. Which will probably take a faster twist to stabilize. Of course a bit more velocity would be a plus. Sorry for any confusion.

 

[cape cove]

I don't believe you would have to concern yourself with throating in the 270 Wea as the free bore in all Weatherby's are long enough to allow for all the case capacity to be used. The problem may be in your magazine length . This may restrict your OAL depending on rifle make. You would also need a faster twist than the standard 1/10 to stabalize the 165's. JMO

 

[FEENIX]

Yes wanting to see how the Wby with the 165s would perform. Which will probably take a faster twist to stabilize. Of course a bit more velocity would be a plus. Sorry for any confusion.

165 LRAB requires a minimum of 1:8.5" twist. As I noted in #2, the twist rate is for stabilization, not velocity. For instance, if your current rifle has a 1:10" 24" barrel and you re-barreled it with 1:8.5" and 24", you will more than likely not gain velocity but will be able to stabilize the 165 LRAB. However, if your barrel length is longer, you will gain velocity ~25 FPS +/- per inch but YMMV.

I have a .270 AI with a 30" 1:8" barrel propelling the 175 Matrix VLD at 2993 FPS with H4831SC. Others are claiming ~100 FPS more with RL-26.

 

[B-LOT Banga]

With my personal tests I've got a 170 FPS difference between my 270 wby mag and 270 wsm. Both are moderate loads and do 1/2 MOA at 300 yds. I've got a 27 Nosler that is hot and can push a littler over 200 FPS over the wby although I've gotten wide groups as the 165 ABLR is finicky with the 27 Nosler, I might try some 170 EOL. All 3 have 1-8" twist barrels.

 

[MagnumManiac]

I have just re-barreled my Win Model 70 from the standard 1:10" twist to a 1:9" twist 270 Weatherby.
Haven't punched any holes with it yet, just ran the barrel in with 130gr BT's in my normal Norma brand brass. It still gets 3500fps with them so no increase in velocity and my old barrel liked the 150g ABLR or 150g Partition for hunting.

Cheers.

 

[fmuguira]

My first rifle was a 270 Win, still have it, great caliber. But I do think it's worth mentioning that a 270 Weatherby is .007" difference than a 7mm Weatherby and the 7mm s have so much more in bullet selection. At least worth some pondering?

If your a .277 diameter guy I get it but just mentioning the bullet selection gap. Good Luck

 

[FEENIX]

My first rifle was a 270 Win, still have it, great caliber. But I do think it's worth mentioning that a 270 Weatherby is .007" difference than a 7mm Weatherby and the 7mm s have so much more in bullet selection. At least worth some pondering?

If your a .277 diameter guy I get it but just mentioning the bullet selection gap. Good Luck

Perhaps, but that is NOT what the OP is asking.

 

[Lenny Foffa]

I also own a .270 Weatherby Mag, its a 10 twist, 26 inch #2 barrel. Mine shoot the 150 Grn Nosler Accubond LR bullets pretty well. I have not even tried shooting my .277 ,170 Grn Berger's out of it. I think it would be just wasting good bullets. I love the way it shoots 130 Grn and 150 Grn , so I have no plans on changing the barrel any time soon. To me its a long range White tail , Mule Deer and Antelope rifle. I took one small elk with this in 1980 in Colorado using the Speer Grand slams . A popular Bullet at that time. Worked pretty well, Needed two shots. One bullet hit the heart, the second was placed in the neck. Until I took the second shot, that animal gave no sign of being hit. On the meat poles back at the lodge , I could see exactly where my bullets went. In my personal opinion, if they made the 270 Weath. mag rifle with a 9 twist , that would allow for the use of longer ,heavier bullets, with greater accuracy of the heavier longer bullets' than its capable of right now with a 10 twist. That would /could make it a great all around caliber. I took a different path ,and in 1982 picked up a used Weatherby Mark V in .300 Weatherby Mag , also 26 inch #2 Barrel, had it Mag -Na Ported and had sights and barrel band added to it. That rifle allowed me shoot at elk with 180 Grn, and 200 Grn bullets. Necessary??? Who Knows!!! Having another Weatherby in the safe??? Nice.

 

[fmuguira]

Perhaps, but that is NOT what the OP is asking.

I realize that thus my mention of if you re a 270 diameter guy "I get it", just thought mentioning bullet selection was a valid point.

As you mentioned Feenix twist is only for bullet stabilization.... some would argue that more twist with the same length barrel will actually lose some velocity due to friction/pressure. Almost theoretical as hard to prove due to other variances such as barrel to barrel differences, etc.

Regardless OP will have a fine cartridge no matter which way he goes! Happy Easter to all !