rate of twist in 223 heavy bullets
looking to broaden my knowledge here. please educate me.
rate of twist is the number of complete turns the the bullet will rotate. 1 in 9 once in 9 inches. 1 in 14 once in 14 inches. smaller ROT bullet spins faster.
how does this affect bullet weight? ok so a lighter buller will spin faster.
i was at gun shop yesterday and they had 64 grain 223 ammo. i am going to buy a savage 12 with 1:9 twist and i plan to shoot varmints/predators with it. in my mind its too light for deer, but winchester has the deer logo on the box. i want to use the 55 gr ball ammo to shoot at the range to improve marksmanship (thats why im buying 223) and i think that ill try a variety of other stuff in it to see what it likes. im not hunting for pelts, just quick clean human kills on coyote and bobcats.
if you have a 223 and you have used heavier bullets in it please post your pos/neg results. i know every gun is different but if i see a trend i may be able to save 25.00 on a box of ammo.
kyle
rate of twist is the number of complete turns the the bullet will rotate. 1 in 9 once in 9 inches. 1 in 14 once in 14 inches. smaller ROT bullet spins faster.
how does this affect bullet weight? ok so a lighter buller will spin faster.
i was at gun shop yesterday and they had 64 grain 223 ammo. i am going to buy a savage 12 with 1:9 twist and i plan to shoot varmints/predators with it. in my mind its too light for deer, but winchester has the deer logo on the box. i want to use the 55 gr ball ammo to shoot at the range to improve marksmanship (thats why im buying 223) and i think that ill try a variety of other stuff in it to see what it likes. im not hunting for pelts, just quick clean human kills on coyote and bobcats.
if you have a 223 and you have used heavier bullets in it please post your pos/neg results. i know every gun is different but if i see a trend i may be able to save 25.00 on a box of ammo.
kyle
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The 64 grain Winchester will make a good light deer bullet, and you don't need any particular twist rate to make them work well. If your gun will shoot them accurately they should be grest for big varmints.
If you move up to a 75 grain bullet such as the excellent 75gr Hornady A-max
you will need at least a 9 twist for it to work as planned, this is also a very good light deer bullet.
The 80 grainers will need at least a 8 twist to work.
The fast twist will spin them a lot faster than a slower twist will.
Light for caliber bullets don't work very well with fast twist barrels.
Gun control is hitting what your aiming at.0 -
Our military has been increasing the bullet weight in an effort to get better longer range effectiveness on human size targets. They have also changed the twist rate to go along with these changes. But not all barrel makers barrels are equal. Some are much more forgiving on the bullet weight and accuracy issues. It rapidly becomes a case of just what does your rifle in particular shoot well. Yes you can design for your intended purpose, I just don't think that you can expect to have 55g bullets and 75g bullets shoot with anything like the same accuracy or even a close point of impact. You probably need to pick one or the other and then hope that the other will be useable. For reasonable range cyotes and such the 55g will do most of what the heavier slugs will do. The AR15 style platform's barrels are readily removed. With an AR15 you can have multipul barrels, it is just a hassel to have to reset the scope with each change ove.
Many of my friends who call cyotes have stopped using .223 caliber rifles on the song dogs as they regularly have had dogs spinning, and biting and crying till they run off or drop. Either way it isn't always quick and clean, so we have mostly moved up to 6mm and 25cal for larger varmints. I'm shooting a 250savage these days for that kind of varmint and still have my 25-06 for when we get into real open spaces.0 -
My bushmaster xm15 has a 1 in 9 twist, according to pushmaster that is sufficient for 55gr-69gr bullets. Anything under 55gr look at the 1-12 for anything heavier than 69gr look at a 1-7twist. Atleast thats what my AR is rated for, not sure if that carries over to 223 in general(as my barrel is designed for 5.56mm and .223) 0 -
[8D]--Yo hawaii-INFO-- Remington 700 BDL, (Bull BBL),.223cal, 1-10 twist, match cases, 55gr fmjbt (Winchester) bullets, 24.2 gr AA2230c powder, 100yds 5-shot-.209" group. The bullets were weighed and seperated by .10 grains(groups),CCI small rifle primers.The bullets for this best group were 55.2 gr's--I don't shoot bench rest quality, but this Rem is once accurate sob--JIMBO
I'm only wearing Black untill they make something darker0 -
Kyle,
"how does this affect bullet weight? ok so a lighter buller will spin faster."
This gets run through here with fair frequency so you can do a search and probably find quite a bit of information.
All bullets spin with the same rotation in given a barrel with a given twist rate. They do not spin faster or slower due to their individual weight.
The easy way to attempt this is to say that it is the length of a bullet that determines the twist rate. Longer bullets require a faster twist to achieve stability. The problem is that most manufacturers only list the weight on the box and this can get confusing because of the shape of the various bullets. Bullets with longer ogives need more twist, solids generally require a little more twist but the shorter, same weight full of lead spitzers can use a slightly slower twist. Some of the manufacturers do list a suggested twist either on the box or in the advertising literature. Check their websites or get their literature. I think that you can call them and request the one page, large illustration of their complete bullet line.
The Winchester ammunition should be fine but if you want to reload then take a look at the 60 gr. Hornady VMAX. It will spin just fine in the 9" twist in the Savage and be terrific for varmints. Just do me a favor, shoot all the coyotes that you want but if you're not going to harvest the fur, leave the Bobcats alone.
Best.
Here is reference chart for the .224 bullet. Note I said reference because none of these are hard and fast rules.
.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
Here is the link for the complete reference:
http://sst.benchrest.com/shilentwist.html
And another at Lilja. Scroll down, middle of page:
http://www.riflebarrels.com/products/caliber_twist_rates.htm
ADDED:
Kyle - I sent you an e-mail with some information regarding twist rate.
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Hawaii,
What Nononsense says is true. Length has more to do rotational need than does weight. However, most bullets being constructed relatively close(Barnes being the exception) the increased weight will increase the length proportionately (usually).
I use the velocity formula to determine what speed I need to put which bullet weight out to get optimal rotation. It is:
.06 x Velocity x Diameter of bullet(squared)/length of bullet.
It is a derivative of the Greenhill formula, which is:
150 x D(squared)/L for under 2800 fps and 180 in place of 150 for over 2800 fps.
This not only tells you what range of bullets work in which speed of rotation, it will help you when you reload to acheive optimal rotation for a given bullet from a given rifle. Example: I have two 7mm Mausers. one with 1-10 and one with 1-12. Only at max velocity will the 1-10 stabilize 175's. The 1-12 won't. Because if you work the math and measure the bullet it requires a 1-8.5 twist. Same as the '93 Mauser that the Spanish used to very good effect effect against us 107 years ago. Conversely, the 1-12 shoots 120's very accurately at max vel. and the 1-10 shoots them better slightly downloaded. Most 6PPC's are 1-14's so that they rotate a lighter(55-68 match) bullet correctly as fast it will push them out. Again, conversely, most .243's and 6mm Rem's are 1-10 to handle up to 100 gr. plus bullets. -hope that helps, good luck
EDIT:
I noted that I should have added my reverse mathology that I mentioned above. I did this using standard algebra.
The original formula of .06 x V x D(sq)/L = T is changed thus: to isolate V I divided both sides by .06 and D(sq), I then multiplied both sides by L. The new formula to get velocity in in known twist is: V=TL/d(sq) then that is divided by .06.
Example; you have a 1-12 twist .308 and Nosler J4 match bullets of 1.189",
12 x 1.189=14.268/ .308(sq)or(.094864 = 150.405 /.06= 2506.75 for velocity.
This is slightly slower than what you would find standard match ammo loaded to of between 2550 or 2650. I hope that clarifies what I meant. Since velocity is the only thing I can change. The bullets have a given dia. and length and the rifle's twist isn't going to change.
We have the second amendment so that all the rest are secure....UNK>0 -
One question I have,..is what is your purpose and range you wish to have your rifle perform at? If you want long range with target accuracy, then a fast twist and heavy pill is necessary. If you want varmints to say 300yds and push it to 400yds,..a 1:12 will get you by with 55gr and even some of the 60-63gr pills. My 1:14's just don't like much over 52gr pills. Now,..if the 40-50gr pill is what you want to use,..the 1:14 and faster will all do a great job. keep in mind though,..a 1:8 or 1:7 may overstabilize the lighter pills as high speeds and cause flyers as range gets pushed out some.
With your 1:9,..I would be loading 55gr pills as a staring point and moving up to the low 60's. A good pill in that range will run hard and tight from a good savage tube. You can probably stabilze up to the 69 and 70gr pills with that tube.
why chase the game when the bullet can get em from here?....
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