Twist Recommendations

[Beluebow]

For 110-115 class bullets and factory ammo all you need is a 10 twist IMO.

See for yourself.....

Twist Rate Stability Calculator

Our newly updated Twist Rate Stability Calculator not only tells you what your SG is, but it also lets you know if you are reaching your optimized BC.

bergerbullets.com

 

[Window]

Roys original intent eh, do tell.

Roys original intent eh, do tell.

With Roy, it was always about speed and in the 40's and 50's optics were simple and range finders were not even a dream at the time. Speed and flat trajectories allowed for, at the time, extending effective hunting ranges. Light for cartridge with excessive speed was his intent. 400 plus yard shots in the field were not considered due to having no way to range. My point with light Hammers or other monos being over spun ie 1:7 would have great terminal performance due to the fact the bullet would have better straight line penetration and less deflection on impact.

 

[Pelicanpoint]

Another question…would a 7.5 twist 26" spin too much for a 120 nosler partition @ 3300fps or would it hold together just fine? According to the Berger twist calculator, it should stabilize with no problem. The reason I ask is that there is a 7.5 26" Proof for sale in the classified section and I have a lead on a bunch of factory 120 partitions. Thanks for all the advice thus far!

 

[FEENIX]

Another question…would a 7.5 twist 26" spin too much for a 120 nosler partition @ 3300fps or would it hold together just fine? According to the Berger twist calculator, it should stabilize with no problem. The reason I ask is that there is a 7.5 26" Proof for sale in the classified section and I have a lead on a bunch of factory 120 partitions. Thanks for all the advice thus far!

All I know is I shot a couple of boxes of ...

... out my .257 WBY with 1:7" without any issues.

 

[Mike D Texas]

Another question…would a 7.5 twist 26" spin too much for a 120 nosler partition @ 3300fps or would it hold together just fine? According to the Berger twist calculator, it should stabilize with no problem. The reason I ask is that there is a 7.5 26" Proof for sale in the classified section and I have a lead on a bunch of factory 120 partitions. Thanks for all the advice thus far!

IMO yes. It would have the bullet rotating at almost 317,000 rpm. Most cup/core bullets are recommended to be kept under 300,000 rpm.

 

[FEENIX]

For 110-115 class bullets and factory ammo all you need is a 10 twist IMO.

See for yourself.....

Twist Rate Stability Calculator

Our newly updated Twist Rate Stability Calculator not only tells you what your SG is, but it also lets you know if you are reaching your optimized BC.

bergerbullets.com

Brother, "IMHO," the 1:10" is too close for comfort when it comes to the SG, and it depends on altitude. For instance, Choice Ammunition from Montana load 115 Berger VLDs (https://choiceammunition.com/produc...-115-grain-berger-vld-hunting100-hand-loaded/) with an MV of 3240 FPS.

SG at sea level with 1:10 is 1.36 (marginal)
SG at my range altitude (3300') with 1:10" is 1.53 (barely stable)
SG at my range altitude (3300') with 1:7.5" is 2.72
SG at my range altitude (3300') with 1:7" is 3.12

I have a 1:7" specifically built for the heavy and long high BC bullets.

Cheers!

 

[sable tireur]

Brother, "IMHO," the 1:10" is too close for comfort when it comes to the SG, and it depends on altitude. For instance, Choice Ammunition from Montana load 115 Berger VLDs (https://choiceammunition.com/produc...-115-grain-berger-vld-hunting100-hand-loaded/) with an MV of 3240 FPS.

SG at sea level with 1:10 is 1.36 (marginal)
SG at my range altitude (3300') with 1:10" is 1.53 (barely stable)
SG at my range altitude (3300') with 1:7.5" is 2.72
SG at my range altitude (3300') with 1:7" is 3.12

I have a 1:7" specifically built for the heavy and long high BC bullets.

Cheers!

With respect, please note the following explanation from the Berger Calculator:

The term 'stability' can be a misnomer here when the explanation isn't stated. As above, Berger represents that 'stability' should be interpreted as the optimization of the BC, not that it is flying true, creating a round hole or grouping poorly in the target. Far too many of us grew up defining stability as how the bullet landed in the paper. Unstable being a keyhole.

Here, Berger states that down to 1.0 SG the bullet will be stable flight-wise but that the BC will suffer. If you're wanting to maximize the BC when using high BC bullets then you need to pay attention to this SG number more closely.

 

[FEENIX]

With respect, please note the following explanation from the Berger Calculator:

View attachment 363575

The term 'stability' can be a misnomer here when the explanation isn't stated. As above, Berger represents that 'stability' should be interpreted as the optimization of the BC, not that it is flying true, creating a round hole or grouping poorly in the target. Far too many of us grew up defining stability as how the bullet landed in the paper. Unstable being a keyhole.

Here, Berger states that down to 1.0 SG the bullet will be stable flight-wise but that the BC will suffer. If you're wanting to maximize the BC when using high BC bullets then you need to pay attention to this SG number more closely.

Yep, that's why "I" noted as too close for comfort. "I" like to keep my SG close to 2 and up. All my fast twist barrels are based on bullets I am going to use.

 

[cantfixstupid]

I have 257BEE 7.5 twist Bartlein 26" built specifically for the 131 Gr BlackJack Ace. I have shot some 100 Gr factory ammo out of it and does very good, shoots about .75 group at 100. I have some 87 grain factories I am going to try before breaking them down for the brass, I think both 100 Gr and 87 Gr are Nosler bullets. I would go with a 7.5 or an 8 Twist because, if you ever reload for it and want to shoot the heavy Hammer or Berger .257's it will make it possible. I have about 250 rounds down mine now and it just keeps getting better. Went from .325 group at load development to an amazing .210 group and an additional 75 FPS +/- gain and I bet it gets better.

 

[sable tireur]

Yep, that's why "I" noted as too close for comfort. "I" like to keep my SG close to 2 and up. All my fast twist barrels are based on bullets I am going to use.

Nice overuse of the quotes.

I point this out on several occasions when the subject comes up because there are a few who have not read the complete explanation for the details. That's why I stated respectfully in my answer. Far too many don't read completely and get some definitions wrong. My point was to clarify not hurt your feelings.

Best.

 

[FEENIX]

Nice overuse of the quotes.

I point this out on several occasions when the subject comes up because there are a few who have not read the complete explanation for the details. That's why I stated respectfully in my answer. Far too many don't read completely and get some definitions wrong. My point was to clarify not hurt your feelings.

Best.

I did not view it as such; no feelings hurt here. It's all good. I know you meant well.

The quotes are for emphasis.

 

[FEENIX]

Another question…would a 7.5 twist 26" spin too much for a 120 nosler partition @ 3300fps or would it hold together just fine? According to the Berger twist calculator, it should stabilize with no problem. The reason I ask is that there is a 7.5 26" Proof for sale in the classified section and I have a lead on a bunch of factory 120 partitions. Thanks for all the advice thus far!

Congrats! I am glad you went with the 1:7.5">https://www.longrangehunting.com/threads/proof-carbon-257-1-7-5-26”.301939/#post-2524506

 

[sable tireur]

Yes, I know this is a few months old but I thought of a little relevant information which might prove useful in whatever small way.

I mentioned in the opening responses about using the .257 Weatherby Extended Range ammunition which was loaded with a Spitzer Boat Tail bullet:

The bullet in the .257 Weatherby was the 122 gr. SP Extended Range bullet. I had a couple of these rifles to test so as usual I bought some factory ammunition to use as a baseline.

The twist rate in both cut rifled barrels was a measured 1:10" which should have been adequate. One was 22" the other 26 inches.

Shooting the 22" first resulted in an anomaly which I thought the spotting scope was creating so I walked to the 100 yard target to observe close up that the impact on paper was showing a light elongation. I walked back and proceeded to shoot the 26" barrel. Same elongated hole in the paper. Thinking all manner of things may have occurred, I moved the target to 300 yards. This resulted in the same elongated holes and not even close to a decent group. Well poop!

I called Remington, had a very nice albeit short discussion and wound up faxing them targets. (Yes, before smartphones...) End thinking was that these should need a 1:9" twist and not 1:10" as suggested on the box. This was all long before the 131 Ace and the 133/135 Berger bullets.

Now I use 1:7.5" for everything .25 caliber and do not see failures with the cup and core bullets as has been suggested. Maybe I'm just special?

Nah.

 

[762n40]

I ran a 25-06AI for a few years, Lilja barrel 1-10 twist and 26" barrel, I was quite happy with the whole package. The quarter bore has become very popular lately and I am seeing some new heavy projectiles coming out. All that said, The 257 weatherby has amazing velocity and I feel the 7 twist is un-needed. The 9 twist is what I'd favor if i were to do another quarter bore. I'd look at getting into reloading though for the weatherby, factory ammo I'd think would be quite pricey.