HuntingNut
HuntingNut
   Login or Register
HomeCommunity ForumsPhoto AlbumsRegister
     
 

User Info

Welcome Anonymous


Membership:
Latest: JoeQ
New Today: 0
New Yesterday: 0
Overall: 12729

People Online:
Members: 0
Visitors: 105
BOT: 1
Total: 106
Who Is Where:
 Visitors:
01: Forums
02: Home
03: Home
04: Photo Albums
05: Forums
06: Photo Albums
07: Photo Albums
08: Photo Albums
09: Your Account
10: Forums
11: Forums
12: Forums
13: Forums
14: Forums
15: Forums
16: Your Account
17: Forums
18: Photo Albums
19: Photo Albums
20: Home
21: Photo Albums
22: Photo Albums
23: Forums
24: Forums
25: Home
26: Forums
27: Photo Albums
28: Photo Albums
29: Photo Albums
30: Photo Albums
31: Photo Albums
32: Photo Albums
33: Forums
34: Photo Albums
35: Forums
36: Photo Albums
37: Photo Albums
38: Photo Albums
39: Forums
40: Forums
41: Photo Albums
42: Forums
43: Forums
44: Photo Albums
45: Photo Albums
46: Photo Albums
47: Your Account
48: Forums
49: Forums
50: Photo Albums
51: Forums
52: Forums
53: Photo Albums
54: Photo Albums
55: Forums
56: Home
57: Forums
58: Home
59: Your Account
60: Forums
61: Home
62: Photo Albums
63: Photo Albums
64: Photo Albums
65: Photo Albums
66: Photo Albums
67: Home
68: Forums
69: Forums
70: Photo Albums
71: Your Account
72: Forums
73: Photo Albums
74: Forums
75: Forums
76: Home
77: Forums
78: Home
79: Photo Albums
80: Forums
81: Home
82: Photo Albums
83: Photo Albums
84: Forums
85: Photo Albums
86: Photo Albums
87: Photo Albums
88: Your Account
89: Home
90: Forums
91: Forums
92: Forums
93: Photo Albums
94: Forums
95: Forums
96: Forums
97: Your Account
98: Forums
99: Forums
100: Home
101: Your Account
102: Home
103: Photo Albums
104: Forums
105: Forums
  BOT:
01: Forums

Staff Online:

No staff members are online!
 

Coppermine Stats
Photo Albums
 Albums: 305
 Pictures: 2378
  · Views: 560529
  · Votes: 1312
  · Comments: 86
 

Support our Advertisers

Twist and Spin
Discussion that doesnt fit other Topics
Go to page 1, 2  Next
Post new topic   Reply to topic   Printer Friendly Page    Forum Index » General

View previous topic :: View next topic  
Author Message
Ominivision1
Super Member
Super Member


Joined: Sep 20, 2010
Posts: 2984
Location: Iowa

PostPosted: Thu Oct 14, 2010 7:06 am    Post subject: Twist and Spin Reply with quote

Was reading a book called firearms and ballistics by brian heard and I knew that bullets spin very fast but never gave it much thought till I read the book. Here's an example:

Muzzle Velocity × 720 divided by twist = rpm

For example:
9 mm bullet at 1200 fps fired in a barrel with a 1 in 10 twist rate will have
a rotational speed of 1200 × 720/10 = 86,400 rpm

0.223′′ bullet at 3000 fps fired in a barrel with a 1 in 12 twist rate will have a
rotational speed of 3000 × 720/12 = 180,000 rpm

Amazing how these things don't fly apart when they exit the muzzle.

_________________
Regards

Limitations are but boundaries created inside our minds.
Back to top
View user's profile Photo Gallery
Vince
Super Member
Super Member


Joined: May 25, 2005
Posts: 14089
Location: Brisbane AUSTRALIA

PostPosted: Thu Oct 14, 2010 11:52 pm    Post subject: Re: Twist and Spin Reply with quote

Ominivision1 wrote:
Amazing how these things don't fly apart when they exit the muzzle.

Oh, but they do on occasion mate. Check out this Utube video. The first group of bullets don't make it any further than about 10 metres before disappearing in a cloud of lead dust.

Bullets disintegrating

Cheers, Vince

_________________
Cheers, Vince Cheers

Illegitimi non carborundum
(Never let the bastards grind you down)

Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God.

"Nulla Si Fa Senza Volonta."
(Without Commitment, Nothing Gets Done)
Back to top
View user's profile AIM Address MSN Messenger Yahoo Messenger Photo Gallery
Elvis
Super Member
Super Member


Joined: Jul 27, 2008
Posts: 7952
Location: south island New Zealand

PostPosted: Fri Oct 15, 2010 1:03 am    Post subject: Re: Twist and Spin Reply with quote

push a standard projectile too fast and it blows up or I reckon more like gets torn apart by centrifugal force.

_________________
You shot it You pluck it !
Them who eats the most duck eats the most feathers!
Back to top
View user's profile
Ominivision1
Super Member
Super Member


Joined: Sep 20, 2010
Posts: 2984
Location: Iowa

PostPosted: Fri Oct 15, 2010 2:04 am    Post subject: Re: Twist and Spin Reply with quote

Vince:

Watched the video, it boggles the mind sometimes as to how fast these things spin, and yet I have recovered cast bullets that were shot through a handgun and found traces of lube on them!!!

_________________
Regards

Limitations are but boundaries created inside our minds.
Back to top
View user's profile Photo Gallery
Vince
Super Member
Super Member


Joined: May 25, 2005
Posts: 14089
Location: Brisbane AUSTRALIA

PostPosted: Fri Oct 15, 2010 2:53 am    Post subject: Re: Twist and Spin Reply with quote

Ominivision1 wrote:
Vince:

Watched the video, it boggles the mind sometimes as to how fast these things spin, and yet I have recovered cast bullets that were shot through a handgun and found traces of lube on them!!!

Yep...when I was into pistol shooting, I regularly found lube on the target face and on projectiles picked up down range. But let's not forget that we don't drive cast boolits anywhere near the velocities that most rifle bullets exit the barrel. To be honest, I never checked the twist of my 586 S&W .357 MAG revolver, but even so, I would be extremely surprised if anything I fired from it exceeded 1600 fps...even my earschplittenloudenboomer loads.

Cheers, Vince

_________________
Cheers, Vince Cheers

Illegitimi non carborundum
(Never let the bastards grind you down)

Live simply. Love generously. Care deeply. Speak kindly. Leave the rest to God.

"Nulla Si Fa Senza Volonta."
(Without Commitment, Nothing Gets Done)
Back to top
View user's profile AIM Address MSN Messenger Yahoo Messenger Photo Gallery
TheBigJonson
Rookie Member
Rookie Member


Joined: Mar 23, 2009
Posts: 16
Location: Mountains of the Moon

PostPosted: Fri Oct 15, 2010 6:26 am    Post subject: Re: Twist and Spin Reply with quote

Ominivision1 wrote:
9 mm bullet at 1200 fps fired in a barrel with a 1 in 10 twist rate will have a rotational speed of 1200 × 720/10 = 86,400 rpm

interesting...and it sounds huge but since the time to target is only a little more than one-tenth of a second, the bullet will only rotate 150 times or so before it hits the target.

_________________
"Nobody remembers who climbed Everest the second time." Nanook
Back to top
View user's profile Photo Gallery
Pumpkinslinger
Super Member
Super Member


Joined: Sep 22, 2007
Posts: 4575
Location: NC foothills

PostPosted: Fri Oct 15, 2010 8:09 am    Post subject: Re: Twist and Spin Reply with quote

Remember that old BS about Black Talon bullets "cutting Like a buzz saw" as they spun? If you do the math you see that they'd probably make one turn or less in the target. If the bullet makes one turn in 10" and penetrates 10" its not exactly spinning like a buzz saw.

_________________
Mike

"I ain't no better than anyone else, and there ain't no one better than me!" Ma Kettle

Back to top
View user's profile AIM Address Yahoo Messenger Photo Gallery
slimjim
Super Member
Super Member


Joined: May 16, 2009
Posts: 7916
Location: Fort Worth TX

PostPosted: Fri Oct 15, 2010 9:24 am    Post subject: Re: Twist and Spin Reply with quote

Thus, the benefits of monolithic bullets when achieving high velocities in high-twist barrels.

_________________
"To anger a conservative, lie to him. To anger a liberal, tell him the truth." - Theodore Roosevelt

"The world is a dangerous place to live; not because of the people who are evil, but because of the people who don't do anything about it." - Albert Einstein
Back to top
View user's profile
Suzanne
Super Member
Super Member


Joined: Jun 27, 2009
Posts: 3311
Location: Eugene, Oregon

PostPosted: Fri Oct 15, 2010 8:00 pm    Post subject: Re: Twist and Spin Reply with quote

That was educational, I thought someone had seen me on the stripper pole spinnin and twistin......least they don't have the video on here....

Suz

_________________
May the moon keep you centered,
May the sun keep you dancing,
And the stars shed light on your dreams.
Back to top
View user's profile
PaulS
Super Member
Super Member


Joined: Feb 18, 2006
Posts: 3764
Location: South-Eastern Washington - the State

PostPosted: Fri Oct 15, 2010 8:51 pm    Post subject: Re: Twist and Spin Reply with quote

Now THAT is something!
Not Suz on a pole - though that might be fun to watch but I was talking about disintegrating bullets. A range aquaintance of mine used to do that with his swedish mauser. I think he was using a modified case with more capacity but it was a long time ago.

_________________
Paul
__________________
Speer, Lyman, Hodgdon, Sierra, and Hornady = reliable loading data
So and So's pages on the internet = NOT reliable loading data
Always check data against manuals
NEVER exceed maximum listed loads
Back to top
View user's profile Send e-mail
Suzanne
Super Member
Super Member


Joined: Jun 27, 2009
Posts: 3311
Location: Eugene, Oregon

PostPosted: Sat Oct 16, 2010 8:04 am    Post subject: Re: Twist and Spin Reply with quote

Would probably not be fun to watch!

I didn't know bullets could do that, my desktop dental handpiece rotates up to 400,000 rpm, but the typical use is around 30,000 rpm. Safety glasses!!

Suz

_________________
May the moon keep you centered,
May the sun keep you dancing,
And the stars shed light on your dreams.
Back to top
View user's profile
Ominivision1
Super Member
Super Member


Joined: Sep 20, 2010
Posts: 2984
Location: Iowa

PostPosted: Sat Oct 16, 2010 8:53 am    Post subject: Re: Twist and Spin Reply with quote

Was finishing up the article and came across something else, I always thought heavier bullets required more twist to stabilize, but apparently bullet weight has nothing to do with twist requirements!! Bullet length is the major factor, it gave me a website to go to with I did and entered the figures for couple of bullets I reload and it came up with proper twist every time. Check it out for your self.

kwk.us/twist.html

_________________
Regards

Limitations are but boundaries created inside our minds.
Back to top
View user's profile Photo Gallery
Ominivision1
Super Member
Super Member


Joined: Sep 20, 2010
Posts: 2984
Location: Iowa

PostPosted: Sat Oct 16, 2010 9:19 am    Post subject: Re: Twist and Spin Reply with quote

To add more fun to this, I was looking at Winchesters model 70 extreme rifle in their catalog and am stumped as to why the .308 takes a takes a 1 in 12 twist and 30/06 takes a 1 in 10. These are the same boollits. Granted there's a 2" barrel length difference, but why the longer twist for the shorter .308 barrel?

_________________
Regards

Limitations are but boundaries created inside our minds.


Last edited by Ominivision1 on Sat Oct 16, 2010 10:15 am; edited 1 time in total
Back to top
View user's profile Photo Gallery
Aloysius
Super Member
Super Member


Joined: Nov 03, 2009
Posts: 2194
Location: B., Belgium

PostPosted: Sat Oct 16, 2010 10:09 am    Post subject: Re: Twist and Spin Reply with quote

10" is shorter than 12", so 1 turn in... means here the .308 Win has a longer twist, maybe because he's meant for lighter (or shorter) bullets + the 30.06 normally can give more fps.
Look at the .300 WM, most of them also in 1 in 10" and the 30-30 Win with most barrels 1 in 12" and some (Marlin) 1 in 10".

One might conclude that for jacketed bullets till 150 grs a twist of 1 in 12" is OK and for heavier bullets the 1 in 10" is recommended.

Just to check: my Winchesters in 30/30 like the 125 and the 150 grs bullets, who is using the Marlin in 30/30 and does he prefer the 170 grs?
Back to top
View user's profile
Ominivision1
Super Member
Super Member


Joined: Sep 20, 2010
Posts: 2984
Location: Iowa

PostPosted: Sat Oct 16, 2010 10:20 am    Post subject: Re: Twist and Spin Reply with quote

Aloysius wrote:
10" is shorter than 12", so 1 turn in... means here the .308 Win has a longer twist, maybe because he's meant for lighter (or shorter) bullets + the 30.06 normally can give more fps.
Look at the .300 WM, most of them also in 1 in 10" and the 30-30 Win with most barrels 1 in 12" and some (Marlin) 1 in 10".

One might conclude that for jacketed bullets till 150 grs a twist of 1 in 12" is OK and for heavier bullets the 1 in 10" is recommended.

Just to check: my Winchesters in 30/30 like the 125 and the 150 grs bullets, who is using the Marlin in 30/30 and does he prefer the 170 grs?

Aloysius:
I corrected my statement, I meant to say longer twist. I have a Marlin 30/30 and it like heavier bullets like 170gr than 150gr as my Marlin has a 1 in 10".

_________________
Regards

Limitations are but boundaries created inside our minds.
Back to top
View user's profile Photo Gallery
Display posts from previous:   
Post new topic   Reply to topic   Printer Friendly Page    Forum Index » General
Page 1 of 2
All times are GMT - 7 Hours
Go to page 1, 2  Next



Jump to:  


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Advertisements
 


Valid CSS! Valid HTML 4.01!
Click to check if this page is realy HTML 4.01 compliant for speed :)

All logos and trademarks in this site are property of HuntingNut.com.
The comments are property of their posters, all the rest © 2011 by HuntingNut.com
Interactive software released under GNU GPL, Code Credits, Privacy Policy

.: Upgraded to DragonFly 9.2 by Dizfunkshunal :.