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trapper72_XD
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Posted: 9/18/2008 3:26:32 PM EST
Very new at this, I thought the twist I needed was 1:7, however most suppliers sell the 1:9 saying there is greater versatility??????????

This build for me will be my SHTF gun in .223, 16in barrel KISS, type of build.

Thank you.
ziarifleman
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Posted: 9/18/2008 3:41:01 PM EST

Get a 1-7, if you can find it, or a 1-8. Places like CMMG and RRA commonly carry those.

Exploding 40 gr SX bullets are less of a problem than cartwheeling 75 grainers.
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flopac55
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Posted: 9/18/2008 3:41:59 PM EST
1:9 is standard but the latest trends involve heavier/longer bullets that require a faster twist rate for (optimal) performance. 1:9 is good but if you have yet to purchase i recommend 1:7. i have a rock river entry tactical with a 1:9. wish i had a 1:7. much rather have the ability to accurately deliver heavier bullets. just my opinion
PUBBOY
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Posted: 9/18/2008 3:56:21 PM EST
1:9 will handle a wider variety of bullet weights than 1:7.

If you will be shooting lots of 55 gr. stuff from Wal-Mart, then 1:9 is fine. If you expect to shoot heavy stuff like 77 gr. then get the 1:7.
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Holmes
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Posted: 9/18/2008 8:53:34 PM EST
My FS2000 has a 1:7 twist, and it doesn't shoot 55gr worth a damn. The best groups I can get with Federal AE, Denel, S&B (all in 55gr) is 5 shots into 3-4 inches.

When I tried out S&B 62gr, it consistently shot 5 shots into <1 inch with an aimpoint and magnifier.

I figured 1:7 would shoot 55gr better than mine does. I don't really get the problem. Is it spinning the light bullets too fast that they destabilize?
war-wagon
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Posted: 9/19/2008 12:58:06 PM EST
[Last Edit: 9/19/2008 1:01:12 PM EST by war-wagon]
Most 1 in 9 barrels will stabalize 75 gr bullets but accuracy suffers to a degree.
The 1 in 9 barrels I've tested were between 2.25" to 2.50" at 100yrds. 69 gr out of
same barrels right around 1" at 100 yrds. At 300 yds all 75 gr bullets were on target,
but the group was a little larger than 69 gr bullets. From what I've read on this site the 69 gr mthp are
nearly as effective as the 75 gr mthp. For self defence 1 in 9 is fine. If your shooting
distance & want extreme accuracy go with a 1 in 8 & heavy bullets. 1 in 7 works good
with most bullet weights. It just depends on what bullet you want to shoot the most.
Dace
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Posted: 9/19/2008 1:18:29 PM EST
[Last Edit: 9/19/2008 1:20:13 PM EST by Dace]
SHTF:

Fact #1 (ceteris parabis): 1/7 will handle anything from 55 grain and up. Anything below 55 grain in the 5.56 platform is all but worthless as a self defense load. No I would not want to be shot with a 40 grain varmint load, but the wounding characterisitics are abismal nonetheless.

Fact #2 (ceteris parabis): 1/9 will handle anything below 69 grains.


Scenario: SHTF has not occured and you are still stocking up on ammunition. The heavier grain ammunition has far supperior wounding capabilities then the lighter stuff. The minimum you should be stocking up on is mil-spec 55 grain like XM-193 if you are at all concerned about self defence. With a 1/7 twist barrel you have significantly more options for self defense ammunition then you do with a 1/9 twist barrel. In this scenario the 1/7 twist barrel is kind because it gives you more self defense options.

Scenario: SHTF and you dont have any ammunition and must raid a store. What do most stores carry? Do they carry a lot of 55 grain and a lot of heavy stuff? Or do they carry mainly varmint loads? My Big 5 Sporting Goods, Dicks Sporting Goods, and Walmart carry lots of varmint ammunition, a lot of 55 grain ammunition, and some 62 grain ammunition. While I don't want to use varmint grain ammunition for self defense it my be my only choice. In this scenarion the 1/9 twist barrel is kind because you can use these types of ammunition.

So ask yourself, which scenario is more likely? For me its #1 I would rather have the plethora of self defense options for my A/R ammunition while buying some for a just in case scenario. #2 won't be an issue if I take care of #1. If I take care of #1 and run out and move into #2, then I probably have more problems then shooting varmint weight ammunition through a 1/7 twist barrel.

kevinb120
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Posted: 9/19/2008 1:58:23 PM EST
1/9 also takes well to .22lr conversions
trapper72_XD
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Posted: 9/20/2008 3:36:18 AM EST
Thanks guys.

How about posting some links with barrels in 1:7, there does not seem to be a lot out there
TheUD
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Posted: 9/20/2008 2:01:23 PM EST
1/9 is the standard if all you pay attention to are the wares sold by companies who will never sell to the US Gov. Show me a Colt (besides that rediculous 6721 which isn't sold to gov't) or FN in 1/9. 1/7 is the standard. It will stabilize anything you put into it. I've shot rounds as light as 40-45gr. 1/9 will have a harder time stabilizing 80gr Sierras than a 1/7 will have with 40-45grs; at least that's been my experience.

I have no idea why 1/9 even exists. 1/7 will easily stabilize the ever so common 55gr rounds that almost everyone shoots.
JM1911
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Posted: 9/20/2008 2:29:11 PM EST
1/8 is the perfect rate of twist. My 1/9s shoot 75 gr.Hornadys fine. My1/7 do fine with 55gr. ammo too. If you are shooting 55gr. stuff 90% of the time 1/9n will be fine. To be honest I could care less what gets sold to the govt. The heart of an AR is the bolt system. Get the best you can.I have 1/7 and 1/9 guns. If 1/8s were available in chrome I'd have those instead of either 1/9 or 1/7.
shamayim
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Posted: 9/21/2008 6:46:06 AM EST
[Last Edit: 9/21/2008 6:48:47 AM EST by shamayim]
You'll see a lot of posts advocating 1 in 7 barrels, supposedly because "they handle the heavier bullets" to which I say BS. My own take is that most of these people just want to have a barrel "just like the Army uses".

There's a reason why the majority of commercial manufacturers use the 1 in 9 as standard twist. It'll handle any weight of bullet up to and including 69 grains. If there was a practical use for 1 in 7 in a civilian rifle, other than target pieces where the heavier bullets are useful, the manufacturers wouldn't hesitate a minute in making 1 in 7 standard for civie pieces as well. At that, most target barrels are rifled 1 in 8, not 1 in 7.

1 in 7 was adopted for issue rifles for one reason only; to stabilize GI tracer ammunition. You buy a 1 in 7 barrel and:

1)55 grain stuff shoots only fair.

2) Anything lighter won't shoot worth a damn.

3: Forget abiout a .22 conversion unit.

You want 1 in 7? Be my guest. But you're giving up more than you're gaining. Better expansion in live targets w/the heavy bullets? From a slug w/muzzle velocity in the 2400 -2500 fps range out of a 14.5-16 inch barrel that most of the wannabes insist on? What a joke.


Dont-Tread-On-Me
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Posted: 9/21/2008 7:43:49 AM EST
I'm a big fan of the 1/7 because it is a "shoot all" at "all ranges" ...lets me shoot the 75's at 300. I won't ever need to do it, but it's fun at the range. I reload 75's.


That doesn't mean the 1/9 is inadequate. In fact, the 1/9 typically shoots the 50-65gr rounds more accurately than a 1/7. Then again, the accuracy difference is insignificant from a self-defense perspective. 1.5" difference in groups won't save your ass.


1/9 will stabilize the 75 and 77gr rounds out to real-world self-defense ranges. People are way too fixated with the idea that they are going to have to shoot at some thug at 150 yards with their ACOG. Just not realistic. Carbine self defense is going to happen at 25 yards and less. At that distance, twist doesn't matter.


One important thing to remember is -- virtually all, if not all cheap bulk blasting ammo is either 55gr or 62gr. I don't know of any 68, 69, 75 or 77gr cheap blasting ammo. I think the cheapest was 75gr PRVI, but that wasn't cheap either. It just wasn't high priced like Hornady TAP.


99% of the shooting you'll do will be with good old 55 or 62gr ammo. Unless you're doing very well financially and can afford to buy and practice with cases of Hornady TAP. Most folks are going to buy smaller quantities to test their firearm with the more expensive self-defense rounds and then an amount they feel they need as magazine stuffers for the SHTF. Reloaders can get the price down to where it's more feasible to practice in quantity.


This removes a lot of the negativity surrounding the 1/9 lately. If you think from a purely practical standpoint, both practice AND self-defense, the 1/9 works. Like I said, you're not going to be shooting anyone at 100 yards in self-defense. Not happening. Maybe law-enforcement will in a stand off situation. Us regular people who are not paid to seek out and engage violent criminals are going to be defending our homes with our AR-15's. The badguy has the element of surprise, and at best you will be defending the interior of your home, or at the very most, just outside it. There won't be any 250 meter down the street shots to fend of wild enraged violent hordes of gang bangers.


Also, too much emphasis on twist and super-bullets. Nothing wrong with getting a faster twist and shooting the most effective bullets you can get. Just consider it icing on the cake. Emphasis should be on skills, not gear. Hits count, not 75gr vs 55gr. Get the best you can by all means, but don't think of it as a make or break deal.


For those guys with 1/9, be happy with what you have. It works. You've already made a quantum leap in effectiveness from using a handgun. Not only in terminal performance, but in the ability to accurately deliver lead. Badguy doesn't care. Shoot them center of mass or in the head with a 55gr from a 1/12, and I assure you their attitude will change in a hurry. Behavioral adjustment will occur.


Even if in some extremely rare case you need to shoot at someone 100 yards away, that 55gr round is going to ruin someone's day. Good old iron sights will work just fine too. I don't think there are many thugs who will have the determination to advance on you or continue the fight after the first blast from your AR. Hit or miss, I'd wager on them RUNNING in the opposite direction. And if not, that's why we have 30rd magazines.

rippersde50
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Posted: 9/21/2008 7:59:22 AM EST

Originally Posted By shamayim:
You'll see a lot of posts advocating 1 in 7 barrels, supposedly because "they handle the heavier bullets" to which I say BS. My own take is that most of these people just want to have a barrel "just like the Army uses".

There's a reason why the majority of commercial manufacturers use the 1 in 9 as standard twist. It'll handle any weight of bullet up to and including 69 grains. If there was a practical use for 1 in 7 in a civilian rifle, other than target pieces where the heavier bullets are useful, the manufacturers wouldn't hesitate a minute in making 1 in 7 standard for civie pieces as well. At that, most target barrels are rifled 1 in 8, not 1 in 7.

1 in 7 was adopted for issue rifles for one reason only; to stabilize GI tracer ammunition. You buy a 1 in 7 barrel and:

1)55 grain stuff shoots only fair.

2) Anything lighter won't shoot worth a damn.

3: Forget abiout a .22 conversion unit.

You want 1 in 7? Be my guest. But you're giving up more than you're gaining. Better expansion in live targets w/the heavy bullets? From a slug w/muzzle velocity in the 2400 -2500 fps range out of a 14.5-16 inch barrel that most of the wannabes insist on? What a joke.[>://




A lot of people have/use XM855 which handles much better in a 1/7 twist barrel. Also long range shooting (300 yards+) requires a 1/7 or 1/8 to keep a longer, heavier round stabilized. From reading Molon's tests, accuracy of 75gr ammo shot out of a 1/9 twist may drop off significantly out past 300 yards. It may still be good enough. I don't know. I have limited experiences with long rang shooting. Either way I would test it before I relied on it.

Here's the way I see it. 1/7 and 1/9 twists should stabilize 55gr to 75gr(the weight range of ammo most likely going to be used against a live target)enough within 100 yards to still hit center mass.

I have both 1/7 and 1/9 twist barrels but shoot 55 gr almost exclusively. Either one shoots good enough(I'm sure BETTER than I can do) for my needs and expectations. I for one do not plan on engaging anything other than paper targets out past 100 yards anyways.

They are both universal twists rates IMO, it just depends on your universal needs


Lumpy196
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Posted: 9/21/2008 8:22:30 AM EST

Originally Posted By shamayim:
You'll see a lot of posts advocating 1 in 7 barrels, supposedly because "they handle the heavier bullets" to which I say BS. My own take is that most of these people just want to have a barrel "just like the Army uses".

There's a reason why the majority of commercial manufacturers use the 1 in 9 as standard twist. It'll handle any weight of bullet up to and including 69 grains. If there was a practical use for 1 in 7 in a civilian rifle, other than target pieces where the heavier bullets are useful, the manufacturers wouldn't hesitate a minute in making 1 in 7 standard for civie pieces as well. At that, most target barrels are rifled 1 in 8, not 1 in 7.

1 in 7 was adopted for issue rifles for one reason only; to stabilize GI tracer ammunition. You buy a 1 in 7 barrel and:

1)55 grain stuff shoots only fair.

2) Anything lighter won't shoot worth a damn.

3: Forget abiout a .22 conversion unit.

You want 1 in 7? Be my guest. But you're giving up more than you're gaining. Better expansion in live targets w/the heavy bullets? From a slug w/muzzle velocity in the 2400 -2500 fps range out of a 14.5-16 inch barrel that most of the wannabes insist on? What a joke.





That post is a joke.
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Posted: 9/21/2008 8:37:53 AM EST
[Last Edit: 9/21/2008 8:40:12 AM EST by Aimless]

Originally Posted By TheUD:


I have no idea why 1/9 even exists.


The military originally was going to adopt 1/9. 1/7 was adopted to stabilize tracers. I would assume since most people shoot no, or very few, tracers that's why the commercial barrels went with 1/9 instead.

I'd bet that less than 10% (probably more like 5%) of civilian ar15s ever have anything heavier than 62 gr fired out of them.
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JM1911
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Posted: 9/21/2008 9:39:03 AM EST
What is technically wrong with it ?

Originally Posted By Lumpy196:

Originally Posted By shamayim:
You'll see a lot of posts advocating 1 in 7 barrels, supposedly because "they handle the heavier bullets" to which I say BS. My own take is that most of these people just want to have a barrel "just like the Army uses".

There's a reason why the majority of commercial manufacturers use the 1 in 9 as standard twist. It'll handle any weight of bullet up to and including 69 grains. If there was a practical use for 1 in 7 in a civilian rifle, other than target pieces where the heavier bullets are useful, the manufacturers wouldn't hesitate a minute in making 1 in 7 standard for civie pieces as well. At that, most target barrels are rifled 1 in 8, not 1 in 7.

1 in 7 was adopted for issue rifles for one reason only; to stabilize GI tracer ammunition. You buy a 1 in 7 barrel and:

1)55 grain stuff shoots only fair.

2) Anything lighter won't shoot worth a damn.

3: Forget abiout a .22 conversion unit.

You want 1 in 7? Be my guest. But you're giving up more than you're gaining. Better expansion in live targets w/the heavy bullets? From a slug w/muzzle velocity in the 2400 -2500 fps range out of a 14.5-16 inch barrel that most of the wannabes insist on? What a joke.





That post is a joke.