[Angky]

Looking at improving accuracy on the gun I don't yet have in my hands! http://rugerforum.net/images/icons/icon7.gif
Looking into barrels and I notice most barrels are 1 in 16, but a few are 1 in 9. The faster twist is for 60-grain Aguila bullets, if I read right.

From my experience with my .223 and .22 Hornet, the faster twist is better at stabilizing any bullet, as long as it doesn't spin it so fast that the bullet flies apart. With the .22 lr, the fps are never up to 2000 fps, so would we expect the bullets to come apart? Or are these non-jacketed bullets likely to disintegrate at the low .22 lr speeds?

Or is there another reason why the 1 in 16 barrels are better for the lighter, faster bullets--like stingers?

 

[Iowegan]

Angky, Shooting lead bullets is a whole different thing than shooting jacketed bullets. To compound the issue, 22 LR bullets are very soft lead. The answer is yes, lead bullets may fly apart when fired in a fast twist rate barrel. There's a huge difference in bullet spin rates. Let's assume a 1250 fps 40 gr bullet, which is a standard high velocity load. The formula for bullet spin in RPM is: 12 divided by twist rate times velocity times 60. For a standard 1:16 twist rate 12/16=.75x1250=937.5x60=56,250 RPM. For a 1:9, 12/9=1.33x1250=1666.66x60=100,000 RPM If you shoot hollow points, the velocity and spin rate are much higher.

AR-15 owners with 22 LR conversion kit have learned this the hard way. Most 40 gr solid bullets will stay together but any bullet lighter or faster will fly apart. Additionally, hollow point bullet construction lends itself to weak tinsel strength.

 

[303lithgow]

Angky, Shooting lead bullets is a whole different thing than shooting jacketed bullets. To compound the issue, 22 LR bullets are very soft lead. The answer is yes, lead bullets may fly apart when fired in a fast twist rate barrel. There's a huge difference in bullet spin rates. Let's assume a 1250 fps 40 gr bullet, which is a standard high velocity load. The formula for bullet spin in RPM is: 12 divided by twist rate times velocity times 60. For a standard 1:16 twist rate 12/16=.75x1250=937.5x60=56,250 RPM. For a 1:9, 12/9=1.33x1250=1666.66x60=100,000 RPM If you shoot hollow points, the velocity and spin rate are much higher.

AR-15 owners with 22 LR conversion kit have learned this the hard way. Most 40 gr solid bullets will stay together but any bullet lighter or faster will fly apart. Additionally, hollow point bullet construction lends itself to weak tinsel strength.

I never gave that a thought in my AR conversion but I've never had a problem. Does give one something to thing about.

 

[Angky]

Iowegan,
Very, very interesting, to say the least!!!!
Sure glad I asked the question.
And I'm sure glad for the answer, full of good info.
Sure gives a guy something to think about (as already stated), and also something to help make plans as to what kind of barrel to put on.
Thanks!
Angky.

 

[LunaticFringeInc]

Lowegan makes some very good points, ones that many often over look when choosing barrel twist rates. Just as bullet weight is important since a heavier bullet is generally a longer bullet, you need to consider bullet material design and velocity. They are major factors that need to be balanced too!

 

[jlh820]

Angky, Shooting lead bullets is a whole different thing than shooting jacketed bullets. To compound the issue, 22 LR bullets are very soft lead. The answer is yes, lead bullets may fly apart when fired in a fast twist rate barrel. There's a huge difference in bullet spin rates. Let's assume a 1250 fps 40 gr bullet, which is a standard high velocity load. The formula for bullet spin in RPM is: 12 divided by twist rate times velocity times 60. For a standard 1:16 twist rate 12/16=.75x1250=937.5x60=56,250 RPM. For a 1:9, 12/9=1.33x1250=1666.66x60=100,000 RPM If you shoot hollow points, the velocity and spin rate are much higher.

AR-15 owners with 22 LR conversion kit have learned this the hard way. Most 40 gr solid bullets will stay together but any bullet lighter or faster will fly apart. Additionally, hollow point bullet construction lends itself to weak tinsel strength.

I posted a msg in Off Topic with a link to a little Excel app that will perform this formula for you. Heres the link to it: http://rugerforum.net/tavern/58419-off-topic-179.html#post788130

 

[Angky]

I posted a msg in Off Topic with a link to a little Excel app that will perform this formula for you. Heres the link to it: http://rugerforum.net/tavern/58419-off-topic-179.html#post788130

I think you did a good thing for all of us.
But something went wrong with the link--for me anyway. I see that it is a secure site -- meaning is starts with https. I think that might be the reason I didn't get in. Maybe it has to be in a non-secure site? (I don't know too much about this computer stuff!)

 

[IFFV]

The AR-15 barrels are either,
1/7--what the Military uses
1/8--Civilian, need some help here.
1/9-the most common.

1/7-- 62grn or higher.
1/8-- I believe 55gr.n to 62grn.
1/9--55grn.
If this is incorrect please help out.
I have a 1/7 & a 1/9.

 

[jlh820]

I think you did a good thing for all of us.
But something went wrong with the link--for me anyway. I see that it is a secure site -- meaning is starts with https. I think that might be the reason I didn't get in. Maybe it has to be in a non-secure site? (I don't know too much about this computer stuff!)

https does mean it's a secure site, but all Google sites use https. What that means is that there is a certificate on the site that guarantees it's actually who and what it says it is.

I just checked it and it seems to be fine. Actually, if failed for me the first time, but then I tried it again and I got the open/save as screen.

Click save if you want to save it or click open if you want it to open in Excel on your computer.

 

[Angky]

The AR-15 barrels are either,
1/7--what the Military uses
1/8--Civilian, need some help here.
1/9-the most common.

1/7-- 62grn or higher.
1/8-- I believe 55gr.n to 62grn.
1/9--55grn.
If this is incorrect please help out.
I have a 1/7 & a 1/9.

IFFV,
This might be better in another thread, but I don't know how to move stuff--or if I'm even supposed to--so I'll answer here with what little I know about the matter.

My .223 has a 1/9 barrel. 35-45grn totally disappears; most bullets never hit the target. 55grn hit all over the place. It shoots 75grn right down the line. 68grn does pretty good too. But that's shooting .223 Remington ammo. I don't know about anything else--except a .22 Hornet (CZ) with a 1/16 twist. Won't put anything in the middle of the target over 40grn. Does pretty good with weights under that.

Now I'm learning about the .22LR in a 10/22 with a 1/16 twist. Got it yesterday, but can't get out to shoot it yet.

Not sure if this means anything of value, but thought I'd throw my experiences with twist rates in as a response to your post.

 

[Angky]

https does mean it's a secure site, but all Google sites use https. What that means is that there is a certificate on the site that guarantees it's actually who and what it says it is.

I just checked it and it seems to be fine. Actually, if failed for me the first time, but then I tried it again and I got the open/save as screen.

Click save if you want to save it or click open if you want it to open in Excel on your computer.

JLH820,
Thanks for the update. Proly works for most folks. I tried with various techniques, and different browsers. But maybe Google doesn't like me (I've cussed their Gmail too much, maybe). Or maybe it just doesn't like my Mac.
Anyhow, I can handle Excel pretty well, so I'll do what you did and just put Iowegan's formula on my computer.
Good idea you had.
Angky.

 

[gunsmoke]

The basic question restarted with dealt with .22 rimfire bullet weights and barrel twists. My question relates primarily to the 60-grain Aguila subsonic load. Will it stabilize OK in the 1:16 rate barrels?

 

[RNGreenHat]

1:9 will work better for that load, but only for that size/weight bullet. You end up with a single-purpose rifle.

 

[laidlerj]

The AR-15 barrels are either,
1/7--what the Military uses
1/8--Civilian, need some help here.
1/9-the most common.

1/7-- 62grn or higher.
1/8-- I believe 55gr.n to 62grn.
1/9--55grn.
If this is incorrect please help out.
I have a 1/7 & a 1/9.

The 1/9 twist rate will usually (dependent on bullet design) stabilize up to 65 gr bullets.

Also, the original M16 (AR15) came with a 1/14 twist, rapidly upgraded to a 1/12. I don't think it was until the M16A2 that they upped it to a 1/7 twist.


Jim

 

[grizz12]

My .223 has a 1/9 barrel. 35-45grn totally disappears; most bullets never hit the target. 55grn hit all over the place. It shoots 75grn right down the line. 68grn does pretty good too. But that's shooting .223 Remington ammo.

The AR-15 barrels are either,
1/7--what the Military uses
1/8--Civilian, need some help here.
1/9-the most common.

1/7-- 62grn or higher.
1/8-- I believe 55gr.n to 62grn.
1/9--55grn.
If this is incorrect please help out.
I have a 1/7 & a 1/9.

I have the SR556 w/1:9 twist rate and will be bullet shopping pretty soon, which of these two statement are correct? Which weight is better suited for an AR style rifle with 1:9 twist?

EDIT - will hand loading change the accuracy? What I mean is this, since I reload, will I be able to play around and get any weight bullet to 1MOA by changing powders and velocity? My end goal is to have the heaviest bullet possible for hunting and plinking. But I dont have the time or money to experiment with all the powder/primer/bullet weight combinations to figure out what really does work best with a 1:9 twist

 

[Iowegan]

I see the topic has drifted to AR-15s and 223 Rem ammo .... let's get back to 22 LRs and 10/22s in this 3 year old thread.

 

[frankP2]

The basic question restarted with dealt with .22 rimfire bullet weights and barrel twists. My question relates primarily to the 60-grain Aguila subsonic load. Will it stabilize OK in the 1:16 rate barrels?

Nope got a box and it keyholes

 

[agksimon]

Looking at improving accuracy on the gun I don't yet have in my hands! http://rugerforum.net/images/icons/icon7.gif
Looking into barrels and I notice most barrels are 1 in 16, but a few are 1 in 9. The faster twist is for 60-grain Aguila bullets, if I read right.

From my experience with my .223 and .22 Hornet, the faster twist is better at stabilizing any bullet, as long as it doesn't spin it so fast that the bullet flies apart. With the .22 lr, the fps are never up to 2000 fps, so would we expect the bullets to come apart? Or are these non-jacketed bullets likely to disintegrate at the low .22 lr speeds?

Or is there another reason why the 1 in 16 barrels are better for the lighter, faster bullets--like stingers?

I read an article that too fast of a twist rate for a given weight can cause the bullet to fly with the nose pointed upward.

 

[Iowegan]

agksimon, I don't know where you read that but it's not true. There's a lot of information in this forum about bullet spin rates. You can do an advanced search for "twist rate" using my screen name and you should get several threads that discuss the effects.