Home Forums Hunting & Shooting Custom Rifles & Wildcats ROT for 22-250?

For bullets 55-65 grains, how would you twist it a 22-250... 1-12", 1-10" or tighter?

Tighter....1 in 8 simply to give you the versatility down the road should you change your mind, or as recently happened to me, change the elevation you are hunting at.


The 1 in 8 will stabilize them all, in all conditions.


The tight twist boys have finally got to me.

1-8. Listen to ingwe.....

Why hamstring it right out of the gate? I'd run a 7...

If you really plan to run a 55 grainer on the low end, I'd twist it 7.

If you plan to sometime use 40 grainers, then 8 twist.

How long are these "55-65" grain bullets? You need a certain amount of RPM to stabilize certain bullets for the utmost accuracy. Since Bullet RPM = MV X 720/Twist Rate (in inches), you can calculate the twist rate required to attain the best accuracy of the pill you are interested in. As an example, I know my 9 twist 22 cal loves around 240,000 RPM's and knowing that, it really depends on how fast you want to push those 22 cal pills Brad. Give me a velocity you are looking at running them and you can easily select the best ROT for the barrel you want to run. Let me give you an example based on the 240,000 RPM threshold I'd like to maintain. Yours may be different, however, it is still easy enough to calculate:

55gr. pill at 3800 fps would require a 1 in 11.5" twist rate barrel to reach the desired RPM of 240,000 to say 260,000. A 1 in 12" twist barrel would require a velocity of around 4,000 fps to properly twist a 55 grain pill. If you increase the twist rate to say a 1 in 10", you will have to drop your velocity down to 3,300 fps to spin that 55 gr. pill to your desired 240,000 RPM.

The question is, how fast are you going to push the 65gr. bullet? Logically, you'd think 3,300-3,400 fps MAX. So a 1 in 10" twist barrel may be you huckleberry in this instance. Hope this helps/makes sense Brad....I wouldn't go 8 or 9 twist unless I was trying to spin 75 or 80gr. pills, but you didn't ask about those heavies. I'm thinking best spin on the bullets you had in mind, as an accuracy standpoint. Keeping in mind that bench rest shooters have learned that using a slightly slower twist rate will increase their accuracy by spinning them at just the right RPM's...

What caused you to decide 240,000 is where it's at? (Besides your particular barrel at 9" twist.)

I'd do 8 Brad. Versatility is a great thing. 40's through 80's safely.

Stuff really dies out of an 8" with 40's. Holy RPM explosion.

I built a 12 twist 22-250 once. I was under the delusion that it would be more accurate with light bullets, and I wanted pelts. I've since proven to myself that fast twists shoot light bullets accurately too...

A 22-250 with 80-90gr bullets would be fun.

It could be anywhere around that figure. 240,000-270,000 etc, just throwing a good round number out there. That may not be where it's at for every bullet, just some of the bullets I've ran in my 9 twist 22 cal. I'm glad you commented, as you see the mathematical aspect of things. I'm sure You know the formula and you may know exactly how fast you like spinning your pills, before they blow to chit or blow your accuracy. This has been discussed quite a bit by bench rest shooters. Those guys have this chit worked down to an exact science. They use big words like Gyroscopic Stability and calculate ROT with the aide of certain other mathematical equations such as the Don Miller formula... Pretty interesting stuff, just throwing it out there....

I took the leap in 1986 and went with a 1 in 12 Shilen #3 @ 25".
Really great accuracy from 45 grain Hornet bullets to the 69 grain Sierra.

This sounds like muzzle loader technology now days, but a 12' or tighter twist will do what you asked .....

I just had a Rem Sporter Contour Lilja in 1:8 twist put on my 700 and it shoots 55-75 grain very well. Have not tried anything else but so far, I really like it.

I have one from Pac Nor that is twisted to one in 7.. also put it on what was formerly a 243., so the magazine is longer than a regular 22.250... the 75 to 80 grain bullets can be seated out longer... and the chamber was throated for that...

I have the formula written down around here somewhere... but it can really turn the RPMs on a lighter bullet, with the velocity and the twist...

as long as it is not a super fragile bullet, like an SPSX or Blitz, they will do just fine...an SPSX, even on a hot summer day... if you watch it come out of the barrel.. it looks like your breathe does during cold weather.... just a puff of foggy air, that's the bullet disintegrating in flight, like 10 to 12 inches out of the barrel...

The most accurate bullets out of my 24 inched barrel on a Ruger SA ( Model 77 Mk2) are the 53 V Max, the 75BTHP and the 80 grain A Max...

The fastest velocity and best accuracy with the 75 and 80 grain bullets mentioned above turned out to be not what I originally thought... I was thinking 4350 or the like.. turned out to be 4064....the 80 AMax is clocking 3350 fps..

Here's what some 80 grain A Max look like, loaded to fit what use to be a 243 sized magazine...



pretty wicked looking, and shoot just as well....

I've only had the 22-250 in 1-14 and 1-12. Have to say 1-8 is hard to argue with given the amount of positive experience here... makes a lot of sense, and I really can't see any downside.

Thanks Gents.

I will disagree with most here. Factory twists have been 1-14 for that past 60 years. All of a sudden we need 1-8 twist?? I don't think so. As a rule, a rifle is most accurate with the minimum twist that will stabilize the given bullet. You said 55-65 grain bullets. They don't need 1-8 twist to stabilize them. There is a downside to overtwisting. You give up velocity, you give up accuracy and you run the risk of prematurely rupturing bullet jackets. If you are going to run 80 grain VLDs- go for the 8 twist. If you are really going to stick with 55-65 use a twist that will get you there but not beyond. If I were building that rifle, I would know that a 1-12 twist will absolutely stabilize 55-65 grain bullets. If available, I might err to 1-11" twist but certainly no need to go faster.

Folks will try to razzle-dazzle you with their anecdotal evidence to the contrary. I think they would have had better results with less twist and there is no way to know unless you have done it. I certainly don't see the point in building a 22-250 to shoot 80 and 90 grain bullets when a 6mm shooting 105 will be MUCH more wind resistant and have much better downrange performance. Unless you are shooting matches in some discipline that requires you to use a 22 it is a waste to twist it so fast.

Twisting a 22-250 to 1-8 to shoot 55-65 grain bullets is like buying an F350 diesel for you daily driver to the office 'just in case you have to pull a trailer some time'.

Dennis, thanks for jumping in as the dissenting voice. You make a good case.

Given 55-65 grain window, the too simple solution is snag a 1 in 10" RAR and run it until you are bored with the accuracy. If you need to scratch an itch with a bullet it wont stabilize, you're into it for about the cost of a rebarrel job and can get the bulk of your investment back with a quick posting in the classifieds.

Got my dad a compact 22-250 RAR as a truck gun for Father's Day a couple years ago. It makes reasonably small clusters on paper and he's so bored it's been poking out the window of his suburban as needed ever since he got it.

GE

8

Mine's an 8.

No regrets.




Dave