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All you ar 15 builders and shooters ? What twist rate do you prefer for you 16" barrels . Or ...


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Old 02-18-2014, 10:29 PM   #1 (permalink)
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All you ar 15 builders and shooters ? What twist rate do you prefer for you 16" barrels . Or just prefer . My has a 1 to 9 twist and I shoot mostly military surplus.
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Old 02-18-2014, 10:39 PM   #2 (permalink)
 
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My DPMS is 1/9 twist as well. I think you'll find that's the most popular twist. But according to this the 1/7 is very popular. So I just disproved my previous comment. I hate it when I argue with myself and lose.

Originally Posted by AR15.com
Twist

The barrel�s twist rate refers to the distance a bullet travels in the barrel to complete a full revolution. For instance, a 1/9" twist means that the bullet will make a complete revolution for each 9 inches traveled in the barrel. Heavier bullets require a faster twist rate to stabilize them correctly, but too fast of a twist rate will potentially cause a bullet to spin apart. For this reason it is important to match a barrel to the bullets being fired. In selecting a single twist rate for the survival AR, either a 1/7" or a 1/9" will serve the purpose best. These barrels are designed for bullets from 55 to 62 grains, and these are the weights that will most likely be used in survival. The 1/9 is the better of the two, but the majority of Colts/military barrels are 1/7.
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Old 02-19-2014, 03:57 PM   #3 (permalink)
 
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1 In 9 is on my 16 inch barrel..........
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Old 02-19-2014, 04:00 PM   #4 (permalink)
 
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It depends on what you plan to shoot. The best accuracy potential is with the slowest twist that will stabilize the weight (actually length) of bullet you choose to shoot. Imo, most of the people touting the 1:7 don't know what they are talking about and would be better off with a slower twist. Look at it this way. Most bolt action 223 rifles are 1:12. Unless you plan to shoot heavy bullets for long range competition or tracers, I see no need to go faster than 1:9.
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Old 02-19-2014, 07:04 PM   #5 (permalink)
 
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I have a strong preference for 1 in 9.
recently the fad is to switch to 1/7 barrels because its "milspec" but thats not such a great idea, but more of a fad really.
I will explain:

The reason ppl mention 1in7 as good because it supposedly stabilizes the 62gr Army issue M855 round better.

There is a kernel of truth to that.. yes the 1/7 does a better job stabilizing the 62 gr than it does the 55gr M193 type and 223 Win type 55gr BUT 1/7 so such a fast twist it BARELY properly stabilizes the 62 gr.
And the 1/9 contrary to internet experts does just as good a job with the 62 gr as does the 1/7.

The reason the 1/7 was milspec barrel (and it almost was 1/9,.. the 1/7 was a last minute change) was the Armys intent to use even heavier bullets such as 75 and 77 gr so in a pinch the M16A2 could be used as a DRM rifle (designated marksman, which is not the same as sniper!)
But these are rare and expensive rounds and none of us will shoot them in quantity.

In reality the 1/9 stabilizes the most common sizes 55gr and 62 gr equally well.
But conversely 1/7 does NOT stabilize 55gr properly and barely does a decent job on 62 gr.

So there is no rational reason to go 1/7 other than wanting the cool milspec factor.
One reason Rock River and Ruger Ar's have such a great reputation for accuracy is (in addition to their great barrels) that they stuck with 1/9 all along.

The tacticool clowns snub them for this reason, but they dont know any better.

However in the end... 1/7 while not perfect in the real world.... does very little damage ot your accuracy.... everything else like quyality of barrel, and of course your skill will be more important.

Even so 1/9 in the proper twist for any AR that is to be fed with 55 (the most common) and 62 ( the 2nd most common) ammo. And anything in between.

1/9 even does a great job with the 69gr matchammo which many will claim "only" the 1/7 can do.

Having said all that since I prefer CHF barrels of machine gun steel (I know its overkill) and they all come in 1/7 (except the rugers) all but one of my ARs are 1/7.. but that is not by design it just worked out that way.

However 1/9 would be (slightly) better all other things being equal, but in practice it makes little if any difference.
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Last edited by Bluez; 02-19-2014 at 08:29 PM.
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