HuntingNut
HuntingNut
   Login or Register
HomeCommunity ForumsPhoto AlbumsRegister
     
 

User Info

Welcome Anonymous


Membership:
Latest: MeatMaster71
New Today: 0
New Yesterday: 1
Overall: 12722

People Online:
Members: 1
Visitors: 108
BOT: 3
Total: 112
Who Is Where:
 Members:
01: Loke > Forums
 Visitors:
01: Forums
02: Forums
03: Forums
04: Forums
05: Forums
06: Forums
07: Forums
08: Tell a Friend
09: Home
10: Forums
11: Forums
12: Home
13: Home
14: Forums
15: Forums
16: Forums
17: Forums
18: Forums
19: Forums
20: Forums
21: Photo Albums
22: Forums
23: Forums
24: Forums
25: Forums
26: Forums
27: Forums
28: Forums
29: Forums
30: Forums
31: Forums
32: Forums
33: Forums
34: Forums
35: Forums
36: Forums
37: Forums
38: Forums
39: Forums
40: Forums
41: Forums
42: Forums
43: Forums
44: Forums
45: Home
46: Forums
47: Forums
48: Forums
49: Forums
50: Forums
51: Forums
52: Forums
53: Forums
54: Forums
55: Home
56: Forums
57: Forums
58: Forums
59: Forums
60: Forums
61: Forums
62: Forums
63: Home
64: Forums
65: Forums
66: Forums
67: Forums
68: Home
69: Forums
70: Forums
71: Home
72: Forums
73: Your Account
74: Forums
75: Forums
76: Forums
77: Forums
78: Forums
79: Forums
80: Your Account
81: Forums
82: Photo Albums
83: Forums
84: Forums
85: Photo Albums
86: Forums
87: Forums
88: Home
89: Forums
90: Forums
91: Your Account
92: Forums
93: Forums
94: Forums
95: Forums
96: Forums
97: Photo Albums
98: Forums
99: Home
100: Forums
101: Your Account
102: Forums
103: Forums
104: Forums
105: Forums
106: Forums
107: News
108: Forums
  BOT:
01: Home
02: Forums
03: Forums

Staff Online:

No staff members are online!
 

Coppermine Stats
Photo Albums
 Albums: 305
 Pictures: 2373
  · Views: 554217
  · Votes: 1312
  · Comments: 86
 

Support our Advertisers

bullet lenght and key holes
Discussion regarding the reloading of ammunition and tuning of loads for accuracy
Post new topic   Reply to topic   Printer Friendly Page    Forum Index » Reloading Ammunition

View previous topic :: View next topic  
Author Message
thres
Rookie Member
Rookie Member


Joined: Apr 16, 2008
Posts: 1
Location: new zealand

PostPosted: Wed Apr 16, 2008 4:13 am    Post subject: bullet lenght and key holes Reply with quote

hey does any one know what length sierra 65 gr bullets are. my bro tryed loading some of them and got some key holes. guessing he got the wrong twist rate. going to work out via the greenlaw formula what weight his gun would prefer.
Back to top
View user's profile
SingleShotLover
Super Member
Super Member


Joined: Dec 26, 2007
Posts: 985
Location: Illinois

PostPosted: Wed Apr 16, 2008 4:54 am    Post subject: Re: bullet lenght and key holes Reply with quote

What caliber is the rifle in question? If it is a .224 caliber (.223, 22/250 etc.) the twist is probably too slow to stabilize the bullet. .223s generally have a 1/12" twist while 22/250s traditionally have a 1/14" twist rate. While either will stabilize bullets up to around 60 grains, anything longer can easily become unstable and key-hole. Many newer rifles are coming out with faster twist rates (notably Savage) that allow heavier (read "longer") bullets to be used in certain rifles.

_________________
If you can't hit it with one, you probably can't with two either!

The biggest problem with a closed mind is that it never seems to come with a closed mouth.

SSL
Back to top
View user's profile Photo Gallery
Pumpkinslinger
Super Member
Super Member


Joined: Sep 22, 2007
Posts: 4564
Location: NC foothills

PostPosted: Wed Apr 16, 2008 8:37 am    Post subject: Re: bullet lenght and key holes Reply with quote

If he loaded some why can't you just measure the length...

If you have Excel I can send you a file to calculate Greenhill twist or length. It's just the basic formula and doesn't factor in velocity over 2000 ft/sec. Over 2,000 ft/sec you can get by with a slightly slower twist than the Greenhill formula calculates.

_________________
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
SwampFox
Super Member
Super Member


Joined: Jul 15, 2005
Posts: 1040
Location: Destin, Florida

PostPosted: Wed Apr 16, 2008 11:00 am    Post subject: Re: bullet lenght and key holes Reply with quote

Thres,
In looking at the Sierra bullet data base, the only bullet close to 65 grains is the 63 grain Sierra .244 Varmiter. It is .76 inches in length with a .231 BC over 2,800 fps and .235 over 2,000 fps.
The data could be out dated but should be close if Sierra has in fact introduced a 65. The Sierra .243 bullets are 60 and 70 gr.
Best,
Ed

_________________
The inherent vice of capitalism is the unequal sharing of the blessings. The inherent blessing of socialism is the equal sharing of misery.
-Winston Churchill
Back to top
View user's profile Photo Gallery
SingleShotLover
Super Member
Super Member


Joined: Dec 26, 2007
Posts: 985
Location: Illinois

PostPosted: Thu Apr 17, 2008 4:50 am    Post subject: Re: bullet lenght and key holes Reply with quote

An interesting formula for determining optimum twist rate is as follows:

180 divided by the length of the bullet in calibers multiplied by the bullet diameter.

Example: If a Hornady 55 grain 22-caliber SP (.224 caliber) bullet is .701" long

.701 (length) / .224 (diameter) = 3.129 (length of bullet in calibers)
180 / 3.129 = 57.53
57.53 X .224 = 12.89" (1 turn in 12.9 inches)

For anticipated velocities under 3,000 fps, the factor of 150 is usually more accurate than the factor of 180.

_________________
If you can't hit it with one, you probably can't with two either!

The biggest problem with a closed mind is that it never seems to come with a closed mouth.

SSL
Back to top
View user's profile Photo Gallery
Display posts from previous:   
Post new topic   Reply to topic   Printer Friendly Page    Forum Index » Reloading Ammunition
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 :.