Barrel Twists

[Il Duce]

While looking for a upper I come across different twists. would someone mind explaining to me what they mean and why one may be better than another. im not looking to build a rifle thats dead on at 1000yd but out to 400 if possible.

[Smith]

The numbers stand for twist per inch. In other words a 1:9 means one twist every one inch. The more twist the faster the bullet will spin. In AR's the current trend is higher twist rates to stabilize heavier bullets. A slow twist rate works better on lighter bullets. If you use a 55g in a 1:11 barrel the bullet will spin so fast that it will wobble and the bullet will actually spin apart (depending on construction. If you use a really heavy bullet say 77g in a 1:7 barrel it won't spin fast enough and will wobble and have terrible accuracy.

A 1:9 or 1:8 with stabilize most common bullets and work pretty good for most all purposes.

[Il Duce]

ok.... so if I am using this for mainly target practice and possibly deer and coyote hunting what twist is best?

[PaiMei]

If you have a 1:9 twist...it simply means the rifling has made one full revolution or "twist" in 9 inches. If you have a 1:7 twist then you have a full revolution in 7 inches. 1:9 has been the most common. Guys that are running heavier loads (due to the fact that they are longer bullets) tend to go for the 1:7. Some offer a compromise 1:8 these days too. Unless your running heavy loads consistently I really wouldn't worry about having the faster twist. I wouldn't call one superior to the other...it just depends on what your doing with the rifle.

[PaiMei]

ok.... so if I am using this for mainly target practice and possibly deer and coyote hunting what twist is best?

If its mainly target and your going to be using cheap 55gr loads 1:9 is fine. Really under a couple hundred yards it isn't going to matter all that much.

[Il Duce]

so something like this will be fine?

Pre-Ban 16" M4 Flattop Upper Chrome Lined M4 A4 Pre ban Chrome Lined M&A Parts, Inc.

[Smith]

Yep.

[Alleycat72]

When you say Target, do you mean a human silhouette at 200 yds or do you mean a 1" dot at 200 yds? If it's the later you need to look into a free floated barrel.

1 in 9 = up to 69 gr

1 in 8 = up to 77 gr

1 in 7 = up to 80 gr

There are some 1 in 6.5s out there for the 90 gr bullets. Velocity plays a roll as well. Higher velocity rounds need a little less twist to stabilize the same bullet. For instance a 24 inch 1 in 8 barrel will stabilize a 77 gr bullet all day long, but cut the barrel back to 10 inches and you will need to go to 1 in 7 or faster. Or drop bullet weight. Most all the heavy bullets are for guns used for out to 600 yds or extra energy to reliably knock a BG on his ass.

[Il Duce]

Deer sized kill zone area at 200-300

[Guest 1shot]

You will not be able to use the 80 gr bullets and load through the magazine. The bullets are too long. You have to shoot them single shot. The 77 grs will work in the magazine. I personally would choose a 1 in 8 twist. It will shoot great with 50 through 77 gr bullets.

[Guest Todd@CIS]

Just me, but really, I don't worry about it much.

16" rifle, 1x9

Scoped heavy barrel, 1x7

I do wish 1x8 was more popular / mainstream...seems to be the best of both worlds.

[redstategunnut]

The numbers stand for twist per inch. In other words a 1:9 means one twist every one inch. The more twist the faster the bullet will spin. In AR's the current trend is higher twist rates to stabilize heavier bullets. A slow twist rate works better on lighter bullets. If you use a 55g in a 1:11 barrel the bullet will spin so fast that it will wobble and the bullet will actually spin apart (depending on construction. If you use a really heavy bullet say 77g in a 1:7 barrel it won't spin fast enough and will wobble and have terrible accuracy.

A 1:9 or 1:8 with stabilize most common bullets and work pretty good for most all purposes.

I'm no expert but I think you have this backwards. I thought the 1:7 twist rate will properly stabilize the heavier rounds that the 1:11 won't.

For what it is worth, I have a Daniel Defense M4 with a 1:7 twist that overstabilizes most 55 grain rounds, causing a wide pattern. It puts 62 grain rounds in a nice tight pattern.

[Smith]

I'm no expert but I think you have this backwards. I thought the 1:7 twist rate will properly stabilize the heavier rounds that the 1:11 won't.

For what it is worth, I have a Daniel Defense M4 with a 1:7 twist that overstabilizes most 55 grain rounds, causing a wide pattern. It puts 62 grain rounds in a nice tight pattern.

I did. I also said 1 twist per "one" inch as opposed to 1 twist per 9 in. (given 1:9). I work nights so that was early "morning" for my brain.

[Capbyrd]

I think the 1:9 is the best bet for most people as well since it will stabilize a heavier bullet like a 69 grain but won't overspin a 55. Since most people punch paper with 55, the 1:9 seems ideal and it is what I use.

[Guest ls2tiger]

I have a Colt LE6920 1:7 that I just got for the heavier target rounds and I have a M&P15 1:9 for the fun blast what you can find rounds. (55gr-62gr) The AR is no sniper rifle so if it hits the target anywhere within the KZ I'm happy. If I shoot 1moa I'm buying drinks that evening and bragging the rest of my life.