Twist for .22-250 and .220 Swift

Sig220_Ruger77

What seems to be the ideal twist rate for the .22-250 and .220 Swift for handling 60-70 grain pills? 1:10 or so? Was just curious because I have a .22-250(1:14) that sends fliers everywhere with 60 gr. pills. I knew it probably wouldn't shoot them very well when I bought it(for nothing bigger then coyotes anyway), but figured I would try them out of curiosity. Thanks in advance.

Jon

nononsense

Jon0322,

The 1:9" twist would probably be the most generically correct but each barrel and the longer VLD bullets can prove to be exceptions. You still have to test the loads and the bullets for stability.

It is important to remember that twist rate is only approximate when discussing weight. Twist rate is based on the length of the bullet so here is a fairly simple calculator:

http://kwk.us/twist.html

This is from Shilen's website for reference to bullet weight:

.224 CF

8" For bullets heavier than 70 gr.
9" For bullets up to 70 gr.
12" For bullets up to 63 gr.
14" For bullets up to 55 gr.
15"* For bullets up to 55 gr. driven 4,100 fps or more
16"* For bullets up to 55 gr. driven 4,300 fps or more

Best.

5mmgunguy

I am shooting 60 gr bullets with a 1-12 twist and they shoot great!

Sig220_Ruger77

Thanks for the responses fellas.

quote:Posted - 10/30/2007 : 12:22:17 AM

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Jon0322022,

One hardis. Ogese Side///. jeueu somen tomy comepind is raging yuu tTY.

Huh?

Jon

sandwarrior

Jon0322,

Sorry about that guys. I was about 1/2 asleep already when I saw the post. I probably went to sleep when I started to type it. Long day yesterday.

I was going to say a friend of mine out in NV uses 60 gr. partitions in his .220 Swift. And he pushes them out of I believe a 1-14" twist. But he pushes them really hard. Along that line something I just found recently with my .257 WBY is that when pushing light bullets really hard, the lighter jacketed Sierra's came apart. I was probably right on the edge of them staying together because they made a 14" group at 100 yds. The Nosler BT's which stayed together made a very nice little 1/2" group. I finally figured out they were coming apart as one of the 100 yd holes had a big wide tear on the side. At 200 we couldn't even see where they were hitting.

My point in all this is you may need to go to the thicker jacket of the partition to get to the speed you need to stabilize that bullet and have it stay together. If shooting Hornady V-max's they might not hold together at super high velocity. That may be rotation too. As the case in my .257 WBY is a 1-10" twist.

In my .223 a 1-9" twist will stabilize 69 gr. SMK's. I have to push the Berger 70 gr. VLD's really hard to get them to stabilize in that twist. With the added speed of both the 22-250 and the .220 Swift I would venture to say a 1-12" will stabilize up to a 75 gr. bullet. Just remember at the upper end you need something that is going to hang together.

Sig220_Ruger77

Thanks Sandwarrior. What you guys are saying is starting to make a lot more sense to me(in a couple of ways[:D]). I have never really payed a lot of attention to twists, etc. until recently so I still have a lot to learn about how that and velocity combines to affect accuracy. The 60 gr. pill that I test fired was a Nosler Partition, but it was Federal factory ammo(claims to be pushed at 3500 fps out of a 24" tube, atlhough those numbers are usually a little inflated). I will work my own load a little hotter and see if I can get them to stabilize at the higher velocities. BTW, my rifle is a Remington SPS Varmint with a 26" heavy bbl. I am really looking into getting a Ruger M77 Target in .220 Swift, but I see they stopped making them and by the time I get the money for one it may be to late(for a new one at least).

Jon