Can someone explain the diff between the 1 in 12, 1 in 9 and the 1 in 7, with the savage 22-250. been wanting to buy one for target and varmint. Can someone shed any light on the subject? Thanks

1:12" is a good twist for varminting. Ought to be good up to and including 60 grain bullets.

1:7" is more a specialty twist for the really heavy target bullets. It's not needed for anything less than the 75/77 grain and bigger stuff. If you're going to shoot the 80 and 90 grain bullets you'll have to have it. The Sierra and Nosler 77s need at least 1:8" or faster. The Hornady 75s supposedly will stabilize in a 1:9" twist. It will be too fast for lighter or more frangible varmint bullets but should be fine for the VMax, BT, Blitzking bullets. It will almost certainly vaporize the SX, Blitz type bullets.

1:9" is kinda a 'tweener twist: faster than you need for varmint bullets but will stabilize the 69 grain target bullets.

LWD

twist is the figure given that gives the bullet one complete rotation in so much length. i.e. 1 in 10 would mean that the bullet would rotate completely in 10"

Go here for the Greenhill charts on twist AND bullet lengths.

twist rates

I have had two .22-250's both with slower twist barrels and both have shot well with lite bullets. The 45 to 50gr seem about as good as it gets.

I have a mini-14 with a 1:10 that shoots 52gr well but haven't tried the 69's and up yet. My AR's are 1:8 I think.

The flat based lead bullets will be shorter and stabilize better in slower twists.

My T/C Pro Hunter in 22-250 has a 1 in 12 twist, so I'm told. From expierance I know that it will shoot 55grain v-max, but it is not nearly so accurate with those as 40grain v-max. 50grain v-max accuracy is somewhere in between.
My question here is two fold. First, why such a big difference in accuracy?
Secondly, what are some things I might do to increase accuracy?

There are some new factors to the twist debate. The major factor involves new lead free bullets, either jacketed compressed powdered metal core or monolithic copper expanding bullets. These bullets are longer for their weight than lead core bullets and require a faster twist to stabilize. In my experience with the lead free offerings, I have discovered two things: These bullets are generally extremely accurate, often surpassing similar lead core bullets when driven at the correct twist rate, but are usually more sensitive to seating depth. They are also extremely destructive to varmints, with the added feature of reduced penetration and ricochet (in the powdered metal core varmint bullet).

I have found that many of these bullets, especially the 6mm (.243) lead free Varmint Grenade will not stabilize in anything less than a 1:10" twist, with optimum performance in a 1:8' twist. This is due to their average length of .974". Fired in a 1:14" twist they would not hit the target backers at 100 yards, and when one finally did it printed sideways. In a 1:8" twist they shot consistently in the .2's and .3's for 10 shots. For certain cartridges, such as the 6XC, a twist of 1:7.5" to 1:8" is used to stabilize the 117 grain TDAC bullet for 1000 yard competition.

In the .22-250 Remington, I tested bullets in Remington 700 based custom barreled rifles and found the compromise twist for all bullets to be 1:9" which would stabilize anything from the 26 grain Varmint Grenade to the 50 grain V.G. and all the lead core bullets such as the 50 and 55 grain. The new Speer 50 grain TNT green lead free did remarkably well. This may also be due to the Speer being an open tip design where the powdered copper alloy core extends to the tip, aligning the static and dynamic (rotational) centers of gravity more closely. Other LF bullets have recessed cores or polymer tips that complicate things.

In other calibers and cartridges, I found that a faster twist also works over a wider range of bullet weight, composition and styles. In the .204 Ruger a standard 1:12" twist works for most bullets from 26 to 39 grains, but some barrels will not stabilize the 39 grain and heavier offerings. A 1:8.5" twist stabilized all weights from the 26 grain varmint grenade to the 50 and 55 grain Berger HPBT with remarkable accuracy. The 26 grain V.G. shot 10 shot .250' groups, while the 50 and 55 grain Berger's went under .5". No bullets displayed any failures from excessive rotation.

The .223 Remington also showed a preference for a 1:9' twist with both lead core and LF bullets. with the 40 grain Nosler BT lead free producing a .206" group. This barrel is a Pac-Nor polygonal 1:9" twist 24" Savage Varmint Contour on a Savage Precision Target Action.

Generally, I choose a faster twist than has been past practice, a twist that will stabilize the longest (or heaviest) bullet contemplated to be used. I have not found any problems related to "over spin" with most of today's bullets, either lead core or lead free. The exception to this would be lead core bullets designed with extremely thin jackets such as the old Sierra Blitz which would self-destruct at higher velocities even in a 1:14" twist (at one time Sierra marketed various .224" bullets as Medium Velocity and High Velocity for that reason). Lead cores can become plastic at high velocity, with lead tipped designs more prone to failing in flight.

I recommend using the bullet twist calculator at: http://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi to determine the minimum twist rate needed.

quote:

jlb021983

if you are going to purchase I'd go 1:9. It will make the .22-250 way more versitile.

quote:

Originally posted by jaybald1:
My T/C Pro Hunter in 22-250 has a 1 in 12 twist, so I'm told. From expierance I know that it will shoot 55grain v-max, but it is not nearly so accurate with those as 40grain v-max. 50grain v-max accuracy is somewhere in between.
My question here is two fold. First, why such a big difference in accuracy?
Secondly, what are some things I might do to increase accuracy?

T/C gets all their barrels in as rifled blanks and chambers them as needed... all of their 22cal blanks are in a 1-12" twist...

I'm surprised you're not getting good results from a 55gr VMax and not much better in the 50gr... both of those bullets shoot extremely well in my 26" heavy barrel... I've also found the WW 64gr sp's shoot well, makes a great deer round... slip it in between a rib and it'll lay'em down quick... I haven't tried any of the other 65gr bullets available, but am planning to in the near future...

I also have a 26" 22K Hornet barrel for the Encore... it won't even think about shooting the 35gr Hornady bullets but a 40gr V-Max is the only bullet I load for it anymore... 12 1/2gr of lilgun, federal sp primer and it'll shoot to one hole all day long...