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Posted: 1/17/2005 5:36:03 AM EST
Hi. What is twist rate. DO I want 1:7 or 1:9 for comp. shooting. (i.e. 4 position, etc.)
Link Posted: 1/17/2005 5:37:50 AM EST
For NRA HP competitions IMO you'd be better off with the 1/7 twist, although most CMP/DCM rifles in stainless steel barrels are 1/8.......

Mike
Link Posted: 1/17/2005 5:44:25 AM EST
[Last Edit: 1/17/2005 5:45:13 AM EST by marcoh]
Consult The Ammo Oracle. When you get there, you may need to use your browser's "find" function today.
Link Posted: 1/17/2005 6:32:30 AM EST
if you are gonna shoot 75-80 grainers go with the 1/7
Link Posted: 1/17/2005 6:42:32 AM EST
I keep a rifle in 1/9 and one in 1/7 to have most ammo covered.
Link Posted: 1/17/2005 8:05:49 AM EST
Either 1/7 or 1/8, you will still need to find what ammo works best out of your particular barrel.

Are you going to be buying the ammo, or reloading it?

Any idea which grain/ how heavy of a bullet you are looking at?
Link Posted: 1/17/2005 8:06:30 AM EST
I have both my DCM gun and my M-4 with 1 in 7 twists. Simplifies the ammo situation. (I can use 77 gr match ammo in either without worrying about stabilization issues)
Link Posted: 1/17/2005 9:06:49 AM EST

Originally Posted By marcoh:
Consult The Ammo Oracle. When you get there, you may need to use your browser's "find" function today.




I get "page can not be displayed errors" for every single topic. That sucks.
Link Posted: 1/17/2005 10:26:24 AM EST
[Last Edit: 1/17/2005 10:28:33 AM EST by marcoh]

Originally Posted By dave223:
I get "page can not be displayed errors" for every single topic. That sucks.



If this page comes up in your browser, use the browser's "find in this page" function with the word "twist". All of the hot links at the top of the page appear to point to the file right on Troy's E: drive today, but all of The Ammo Oracle text is available if you scroll down and/or use the "find in this page" function.
Link Posted: 1/18/2005 4:30:24 AM EST
Can I still shoot low grain bullets with a 1:7?
Link Posted: 1/18/2005 4:44:54 AM EST
Varmint cartridges (40gr) will be overstabilized causing them to spin themselves apart. That's also there in the Ammo Oracle.
Link Posted: 1/18/2005 5:00:15 AM EST
Can I still shoot a "normal" AR-15 bulletwith 1:7?
Link Posted: 1/18/2005 5:03:55 AM EST

Originally Posted By DanielL:
Varmint cartridges (40gr) will be overstabilized causing them to spin themselves apart. That's also there in the Ammo Oracle.



While true, this is mentioned there in the Ammo Faq, IRL I have shot the value-box Winchester 45grn. HP extensively in my 1/7 twist M4s and brouhaha has shot the 40 grn. rounds outta his 1/7 twist rifle and NEITHER has shown a propensity to sling themselves apart......

IMO and based on testing in my first 1/7 twist M4, this twist rate is compatible with bullet weights from 40grn. through 77grn. bullets with NO problems whatsoever and was the main contributing factor in causing me to switch to the 1/7 twist for all my M4s and SHTF ARs, (the one exception being my long range CR6724, which shoots the 77grn. SMKs from it's 24" barrel)

Mike
Link Posted: 1/18/2005 5:39:05 AM EST

Originally Posted By mr_wilson:While true, this is mentioned there in the Ammo Faq, IRL I have shot the value-box Winchester 45grn. HP extensively in my 1/7 twist M4s and brouhaha has shot the 40 grn. rounds outta his 1/7 twist rifle and NEITHER has shown a propensity to sling themselves apart......

IMO and based on testing in my first 1/7 twist M4, this twist rate is compatible with bullet weights from 40grn. through 77grn. bullets with NO problems whatsoever and was the main contributing factor in causing me to switch to the 1/7 twist for all my M4s and SHTF ARs, (the one exception being my long range CR6724, which shoots the 77grn. SMKs from it's 24" barrel)

Mike



There's a real life test for you there.. 1/7 seems to work for most weights. It'll also work with normal (55grain) ammo.

Personally, I wish RRA offered a 1/7 twist in their barrels. I'd prefer it over 1/9.
Link Posted: 1/18/2005 3:43:21 PM EST
thank you.
Link Posted: 3/17/2005 5:09:05 AM EST
tag

almost posted the same topic, then remembered search fuction.
Link Posted: 3/17/2005 5:12:07 AM EST
If you don't plan on shooting above 69 grains the 1/9 will work just fine. 1/7 will handle the 70-80 gr rounds much better.
Link Posted: 3/17/2005 5:16:40 AM EST

Originally Posted By j-fonz:
If you don't plan on shooting above 69 grains the 1/9 will work just fine. 1/7 will handle the 70-80 gr rounds much better.



That's my take on the 1:9 twist as well. I also think that the 1:7, in my experience, runs great for grains between 62 and up. People will of course chime in to say they shoot 45 grain bullets from their 1:7 barrels and 77 grain bullets from their 1:9's....so take it all with a grain of salt and make your final decision from your acquired knowledge after reading the ammo oracle.

Generally...

55-69 grains 1:9

62-77 grains 1:7

If you're a varmint, target, and zombie shooter, get a 1:9

If you're a competition, target, and zombie shooter, get a 1:7
Link Posted: 3/17/2005 5:56:12 AM EST

another vote for 1:7
Link Posted: 3/17/2005 6:37:09 AM EST
I'm a 1/7" guy myself. It does everything the 1/9" can do, and more.
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