HuntingNut
HuntingNut
   Login or Register
HomeCommunity ForumsPhoto AlbumsRegister
     
 

User Info

Welcome Anonymous


Membership:
Latest: barcoo59
New Today: 0
New Yesterday: 1
Overall: 12598

People Online:
Members: 0
Visitors: 76
BOT: 1
Total: 77
Who Is Where:
 Visitors:
01: Forums
02: Forums
03: Forums
04: Forums
05: Forums
06: Photo Albums
07: Forums
08: Forums
09: Photo Albums
10: Forums
11: Forums
12: Forums
13: Forums
14: Forums
15: Forums
16: Forums
17: Forums
18: Forums
19: Forums
20: Forums
21: Photo Albums
22: Forums
23: Forums
24: Forums
25: Home
26: Home
27: Forums
28: Forums
29: Forums
30: Forums
31: Forums
32: Forums
33: Photo Albums
34: Forums
35: Forums
36: Forums
37: Forums
38: Forums
39: Forums
40: Forums
41: Forums
42: Forums
43: Forums
44: Photo Albums
45: Forums
46: Forums
47: Forums
48: Photo Albums
49: Forums
50: Photo Albums
51: Forums
52: Forums
53: Forums
54: News
55: Forums
56: Forums
57: Forums
58: Forums
59: Forums
60: Forums
61: Photo Albums
62: Forums
63: Forums
64: Your Account
65: Forums
66: Photo Albums
67: Forums
68: Forums
69: Forums
70: Your Account
71: News
72: Photo Albums
73: Forums
74: Forums
75: Forums
76: Forums
  BOT:
01: Forums

Staff Online:

No staff members are online!
 

Coppermine Stats
Photo Albums
 Albums: 305
 Pictures: 2360
  · Views: 393589
  · Votes: 1309
  · Comments: 86
 

Support our Advertisers

Muzzleloader bullet spin rate
Discussions related to Guns and Firearms

View previous topic :: View next topic  
Author Message
iowafarmboy
Member
Member


Joined: Mar 11, 2009
Posts: 109

PostPosted: Fri Jan 08, 2010 4:04 pm    Post subject: Muzzleloader bullet spin rate Reply with quote

Has anyone ever figured out if the bullet spin rate has anything to do with accuracy? Especially if using a sabot where the centrifugal force opens up the petals the instant it leaves the barrel. I have a 1 in 28 inch twist and a muzzle velocity of 2066 fps. Am I correct in saying that at the muzzle the bullet is spinning at 885 rpm. As the bullet slows does the spin rate drop with it? I had a 25/06 and I calculated that bullet spin rpm at 4,067 with a 1 in 9 twist.

I have noticed that the Barnes TMZ sabots (4 petals) open up uniformly and drop off quickly. The Shock Wave E-Z sabots (2 petals) almost always just drops one petal that breaks off and the other remains intact in it's original position. On virgin snow you can see where the E-Z sabots hit the ground at very high speed and much farther out from the muzzle.

At least in my rifle, the TMZ's are more expensive but they are the most accurate. I have never seen any distortion in a Barnes sabot base but often (especially in warmer weather) i see it with the E-Z sabots. Instead of an "O" shape they are an "0" shape. These are summer pictures. The winter E-Z sabots don't seem so distorted and the Barnes sabots are opened up a full 90 degrees.



sabot_shock-wave.jpg
 Description:
summer sabots
 Filesize:  47.22 KB
 Viewed:  1863 Time(s)

sabot_shock-wave.jpg


sabot_barnes.jpg
 Description:
summer sabots
 Filesize:  39.05 KB
 Viewed:  1863 Time(s)

sabot_barnes.jpg

Back to top
View user's profile
chambered221
Super Member
Super Member


Joined: Aug 17, 2007
Posts: 3455
Location: Lost for good !!!

PostPosted: Fri Jan 08, 2010 6:54 pm    Post subject: Re: Muzzleloader bullet spin rate Reply with quote

Your correct with 885 but it is RPS (revolutions per second) multiply that by 60 to get RPM’s, in your case that’s 53,100 RPM.
Your 25-06 looks about right but you didn’t give the velocity and that’s also RPS not RPM.

Spin rate has everything to do with accuracy !!!
The twist of the barrel and velocity determine the spin rate, if to slow of a twist is used then you will not have enough spin rate to stabilize the bullet.
Think in terms of a spinning top.

When it comes to sabots I was always told broken petals and distorted bases meant you were getting blow by (not sealing) or you running more pressure than what it was designed for. (back down on the powder)
About 5 or so years ago I ran into this when I switched to Triple 7.

The higher temperatures of summer is most likely the cause for more damage to the sabot. (your creating more pressure) I’m assuming your using the same amount of powder in both summer and winter.

_________________
Ask as many people needed, sooner or later your question will be answered the way you want it answered !!!

A free people ought not only to be armed and disciplined, but they should have sufficient arms and ammunition to maintain a status of independence from any who might attempt to abuse them, which would include their own government.
~George Washington
Back to top
View user's profile Photo Gallery
chambered221
Super Member
Super Member


Joined: Aug 17, 2007
Posts: 3455
Location: Lost for good !!!

PostPosted: Fri Jan 08, 2010 7:18 pm    Post subject: Re: Muzzleloader bullet spin rate Reply with quote

iowafarmboy wrote:
As the bullet slows does the spin rate drop with it?
Forgot this part !!! oops !!!

Yes it does but at a slower decent and usually not enough to affect stability.
Somewhere in the neighborhood of 600-1,000 yards seems to be where long range shooters start being concerned with adding a little extra twist but this is of great debate without any definitive answers.

_________________
Ask as many people needed, sooner or later your question will be answered the way you want it answered !!!

A free people ought not only to be armed and disciplined, but they should have sufficient arms and ammunition to maintain a status of independence from any who might attempt to abuse them, which would include their own government.
~George Washington
Back to top
View user's profile Photo Gallery
iowafarmboy
Member
Member


Joined: Mar 11, 2009
Posts: 109

PostPosted: Fri Jan 08, 2010 9:18 pm    Post subject: Re: Muzzleloader bullet spin rate Reply with quote

That's AMAZING! No wonder the sabots open so nice. I forgot one thing. The summer sabots were fired in the old barrel. It was about .004 undersize from the breech to about 8 or 10 inches out. That's why I got a new barrel. The breech plug leaked so bad I'd hate to guess how much pressure was lost. So I'm starting over. I'm trying some different sabots with different bullets and powder loads to find a good combination. In the old barrel I had the best luck with 300 grain bullets. I think it's that the bullets are just a little longer. I'm hopeing to get good results from 250 grain bullets with the new barrel. The numbers look slightly better with 250 grain bullets plus they shoot just a little flatter. Thanks for the info.
Back to top
View user's profile
Display posts from previous:   
Post new topic   Reply to topic   Printer Friendly Page    Forum Index » Gun & Firearm Discussions
Page 1 of 1
All times are GMT - 7 Hours



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 :.