Calguns.net  

Home My iTrader Join the NRA Donate to CGSSA Sponsors CGN Google Search
CA Semiauto Ban(AW)ID Flowchart CA Handgun Ban ID Flowchart CA Shotgun Ban ID Flowchart
Go Back   Calguns.net > INTERESTS AND ACTIVITIES > Ammo and Reloading
Register FAQ Members List Calendar Mark Forums Read

Ammo and Reloading Factory Ammunition, Reloading, Components, Load Data and more.

Reply
 
Thread Tools Display Modes
  #1  
Old 01-09-2011, 4:33 PM
alex45auto's Avatar
alex45auto alex45auto is offline
Senior Member
 
Join Date: Dec 2008
Location: Riverside, CA
Posts: 997
iTrader: 99 / 100%
Default Best Bullet weight for AR 1/7 and 1/9 twist?

What bullet weight would be best to use for AR .223 or 5.56 1/7 and 1/9 twist? What effect would using 55 gr and 62 gr bullet have on either twist rate?
Reply With Quote
  #2  
Old 01-09-2011, 4:44 PM
1lostinspace's Avatar
1lostinspace 1lostinspace is offline
Calguns Addict
 
Join Date: Oct 2006
Posts: 7,864
iTrader: 28 / 100%
Default

For 1:7 77SMK for 1:9 69SMK

Both will stabilize 55-62gr
__________________
There are sniper everywhere and nowhere.....who knows what is out there.

PUREMMA
MIXED MARTIAL ARTS ACADEMY
Reply With Quote
  #3  
Old 01-09-2011, 5:52 PM
killshot44's Avatar
killshot44 killshot44 is offline
Veteran Member
 
Join Date: Nov 2009
Location: Nor Cal
Posts: 4,019
iTrader: 29 / 97%
Default

Oh, man, here we go again.......
Seriously, do a simple search for "twist rate" over in Centerfire Rifles and you'll read all the opinions; some substantiated, some not.

The 1/9 works great to 69gr and, in a true .223 chamber, it may even shoot 75s.
The 1/7 NATO-twist was intended for shooting very long tracer projectiles and to stabilize bullets in extremely cold weather.

The best? It depends on what you'll shoot. The most versatile?, definitely 1/8. But that's uncommon is 16"ers.

Last edited by killshot44; 01-09-2011 at 5:55 PM..
Reply With Quote
  #4  
Old 01-09-2011, 6:41 PM
BigBronco's Avatar
BigBronco BigBronco is online now
CGSSA Specialist
CGN Contributor
 
Join Date: Jul 2009
Location: 221 B. Baker St.
Posts: 5,314
iTrader: 154 / 100%
Blog Entries: 2
Default

So I feed my 1 in 9 mostly 55's. If I wanted to load some match grade target rounds. What bullet is recommended?
Reply With Quote
  #5  
Old 01-09-2011, 6:54 PM
Rock6.3's Avatar
Rock6.3 Rock6.3 is offline
Senior Member
 
Join Date: Nov 2010
Location: Shasta County California
Posts: 2,444
iTrader: 2 / 100%
Default

Quote:
Originally Posted by BigBronco View Post
So I feed my 1 in 9 mostly 55's. If I wanted to load some match grade target rounds. What bullet is recommended?
At short distances 55gr will be sufficient.
Wind + 300 yards? A heavier projectile with a better ballistic coefficient will yield better results. Technically a 1:9 twist should be able to stabilize up to 69 grains.
__________________
Reply With Quote
  #6  
Old 01-09-2011, 6:57 PM
stphnman20's Avatar
stphnman20 stphnman20 is offline
Calguns Addict
 
Join Date: Feb 2005
Location: SCV
Posts: 6,625
iTrader: 26 / 100%
Default

My 1:8 will eat anything from 55gr up to 77gr.. It's love 69gr smk.
Reply With Quote
  #7  
Old 01-09-2011, 8:12 PM
GeoffLinder's Avatar
GeoffLinder GeoffLinder is offline
Senior Member
 
Join Date: Jul 2009
Location: Pacifica, CA
Posts: 2,425
iTrader: 0 / 0%
Default

1:7 and 1:9 (1:8 also) are all pretty much guaranteed to do well with 55gr through 69-70gr bullets. Many 1:9 barrels will stabilize 77gr, but not always, just have to test and see. heavier than 77gr need 1:8 or 1:7 twist barrel to stabilize properly.

The fact to remember here is that you do not need to specifically shoot 77's in a 1:7 and 55 in a 1:9. The real truth here is you just need to find a bullet type and bullet weight that your barrel likes.

The Hornady bulk 55gr FMJBT (Full Metal Jacket Boat Tail) that are available here have shot well in every AR I have (1:7, 1:8 and 1:9 twists).

http://www.midwayusa.com/viewProduct...ber=1165165907


If you want a bullet that will almost certainly perform well in 1:7 and in 1:9 then don't look any further than the Sierra SMK69 or the Hornady 68 grain HPBT. Both are pricey but both are good bullets.

Try the Hornady 55gr FMJBT first and if they shoot well in both barrels you can just stop there. I would not hesitate to shoot these in wind out to 300+ meters if need be. I won a practical rifle stage at a regional 3gun match with the Hornady 55gr FMJBT shooting falling steel at 250-300 yards in a 15-20 MPH wind a few years back. They are very good match grade bullets if you aren't trying to print benchrest style bughole groups and can get by with basic MOA performance. Being a boat tail they handle wind very well if you push them 3100fps or better.

The most important thing to do is not just try a specific bullet, but to also test that bullet through each rifle at a range of velocities and look for a velocity that provides the smallest group size in THAT rifle if you are looking at best accuracy.

IME, the Hornady will hold near or at MOA over most any charge weight of any good .223 power in most any AR IF that rifle is capable of holding MOA in the first place.

Last edited by GeoffLinder; 01-09-2011 at 8:18 PM..
Reply With Quote
  #8  
Old 01-09-2011, 9:22 PM
MTG Firearms's Avatar
MTG Firearms MTG Firearms is offline
Vendor/Retailer
 
Join Date: Dec 2008
Location: Near Sacramento
Posts: 1,544
iTrader: 67 / 100%
Default

I agree with Geoff. I have four rifles with twist rates being 1 @ 1:9, 2 @ 1:7 and one in 1:8 and they all shoot the 55 gr hornady fmjbt reloads really well. My long range load is a SMK 77 grain and the best results are achieved with 1:7 and 1:8 twist rate.
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump



All times are GMT -8. The time now is 6:45 AM.




Powered by vBulletin® Version 3.8.9
Copyright ©2000 - 2016, vBulletin Solutions, Inc.
Proudly hosted by GeoVario the Premier 2A host.
Calguns.net, the 'Calguns' name and all associated variants and logos are ® Trademark and © Copyright 2002-2016, Calguns.net an Incorporated Company All Rights Reserved.