Twist rate question, 1/7 or 1/9

[tonyfac]

I am almost done with a new AR i am putting together, got everything except the barrel and handguard. So i started looking into barrels and i am going with a 16" m4. I can get the exact same barrel (5.56) in either 1/7 or 1/9 twist. Is there a big difference between the two? My 20" is a 1/9, so that 's what i was thinking of staying with but now it got me wondering.

On another note: I am also looking at midwest ind. aluminum quad rail guards. woulld these get too hot in rapid fire situations?
thanks

[Bravo Whiskey]

I am not an expert. I have a 1/7 in my AR and it is fine w/ 55gr.
The 1/7 allows you to take advantage of all the heavier bullets that are coming out. I just read another good study regarding the effectiveness of these rounds ("---Duty Ammo --- from another froum). In the future I plan on buying 90% 62gr. or better. I also believe that all the new Carbines Sped'd for the services are to be 1/7's so you know where the ammo world will be migrating towards.

[Rundownfid]

For varmint hunting one might want a light 30-50 gr bullet as the speed will let it shoot flatter at moderate distance 200-400yds?). If you have an AR it probably doesn't much matter as the typical 50-69 gr bullets generally shot in ARs work very well with both 1-9 & 1-7.
If you have a tactical rifle that you want to go really long range with then by all means get the 1-7 as you will be using bullets in the 69-80 gr range.

[orionz06]

I am almost done with a new AR i am putting together, got everything except the barrel and handguard. So i started looking into barrels and i am going with a 16" m4. I can get the exact same barrel (5.56) in either 1/7 or 1/9 twist. Is there a big difference between the two? My 20" is a 1/9, so that 's what i was thinking of staying with but now it got me wondering.

On another note: I am also looking at midwest ind. aluminum quad rail guards. woulld these get too hot in rapid fire situations?
thanks

The purpose of the gun should define the twist rate. MI rails will not get any hotter than any other rail, and generally they help cool the gun. I would suggest looking into a smaller rail as MI rails tend to be on the large (heavy) side. Troy TRX Extremes are great and cheap.

[mojo]

As others have said, it really depends on the application.

1/7 is great for longer/heavier bullets
1/9 is better for short/lighter bullets

I would say that the 1/9 is a better "all purpose" twist rate as most people shoot 55gr bullets.

[orionz06]

As others have said, it really depends on the application.

1/7 is great for longer/heavier bullets
1/9 is better for short/lighter bullets

I would say that the 1/9 is a better "all purpose" twist rate as most people shoot 55gr bullets.

1/7 will effectively shoot 55gr and allow the use of heavier defensive rounds. I don't know many people who side towards the lighter rounds. One thing to note though, each 1/7 barrel will perform differently with 55-62gr bullets.

[mojo]

1/7 will effectively shoot 55gr and allow the use of heavier defensive rounds. I don't know many people who side towards the lighter rounds. One thing to note though, each 1/7 barrel will perform differently with 55-62gr bullets.

Will 1/7 effectively shoot 55gr? Yes. Will it be as accurate as 1/9, not likely. A lot of people are just buying wolf so they are getting 55gr or 62gr.

[orionz06]

Will 1/7 effectively shoot 55gr? Yes. Will it be as accurate as 1/9, not likely. A lot of people are just buying wolf so they are getting 55gr or 62gr.

Thats where the nature of its use comes into play. If you are using an Aimpoint, even with a 3x magnifier (which is a legit HD gun), you wont be able to notice the fall off in accuracy, especially with a 4 moa dot.

There are also more variables in play than twist rate alone. See this thread.

My experiences are with bargain bin guns and some friends and there were no differences between an old colt with 1/7 and a newer RRA with 1/9 when we were using a rest at a SGL range. But again, reading that he is getting a 16" "m4 type" barrel indicates that minute of bad guy is sufficient, both twist rates will accomplish this.


ETA: Some more links on the subject

http://www.m4carbine.net/showthread....ght=twist+rate
http://www.m4carbine.net/showthread....ght=twist+rate

[mojo]

Thats where the nature of its use comes into play. If you are using an Aimpoint, even with a 3x magnifier (which is a legit HD gun), you wont be able to notice the fall off in accuracy, especially with a 4 moa dot.

There are also more variables in play than twist rate alone. See this thread.

My experiences are with bargain bin guns and some friends and there were no differences between an old colt with 1/7 and a newer RRA with 1/9 when we were using a rest at a SGL range. But again, reading that he is getting a 16" "m4 type" barrel indicates that minute of bad guy is sufficient, both twist rates will accomplish this.


ETA: Some more links on the subject

http://www.m4carbine.net/showthread....ght=twist+rate
http://www.m4carbine.net/showthread....ght=twist+rate

Yep I agree, which is why I still stand by this my first post.

As others have said, it really depends on the application.

1/7 is great for longer/heavier bullets
1/9 is better for short/lighter bullets

I would say that the 1/9 is a better "all purpose" twist rate as most people shoot 55gr bullets.

I haven't read the m4c threads, but yes there always a number of variables that effect this stuff. I just think that the above is a good generalization.

[orionz06]

Yep I agree, which is why I still stand by this my first post.

I haven't read the m4c threads, but yes there always a number of variables that effect this stuff. I just think that the above is a good generalization.

It isn't absolutely terrible, but how many people shoot 44gr Hornaday varmint rounds through an AR? Especially a 16" gun?