Barrell length and rate of twist

[jtech]

Got the itch to buy a bllack gun for long distance shooting. Was wondering what everyones opinions are, 16 in. barrell 1-7 twist or 20 in. 1-9 and why? Was in the Army years ago and realy liked the way the m16a1 shot. They had a 20 in. barrell but slower 1-12 twist. I know with the heavier bullets 1-12 is to slow.
How heavy a bullet will the 20 in. 1-9 barrell stabalize?
thanks in advance for any input.

[Arier Blut]

.224 CF
- 7" for bullets heavier than 80gr.
- 8" for bullets up to 80gr.
- 9" for bullets up to 70gr.
- 12" for bullets up to 63gr.
- 14" for bullets up to 55gr.
- 15" for bullets up to 55gr. driven 4,100 fps or more
- 16" for bullets up to 55gr. driven 4,300 fps or more

The above is a copy and paste from Douglas Premium Barrels.
Bear in mind if you want to shoot lighter bullets the 1-7 and 1-8 will both shoot 55gr. Below that the 1-7 does not do well and may even over rotate 40 gr varmints and cause them to come apart. Personally I have a 9 that is my hunting rifle for varmints. My short barrel is a 7 for defense. It just depends what you are after. If long range or bigger targets you may want a 7. If just shooting bulk ammo or varmints out to 400 a 9 will be fine. If you want over 400 on varmints you may have to move up to heavier bullets. 400 is my max range on varmints so I'm fine with the 9".

Barrel length is just a personal preference as well. For varmints I like the 20"(walking) and 24"(stationary) for the added velocity. For defense I like a 16", giving up a little velocity, energy and sound for a compact size.

[sk330lc]

For your needs . The 20" 1-9" twist will serve you well.  you'll be able to shoot 45gr up to about 75gr bullets well. The 55gr and 60gr Bullets will treat you best. 

[Lloyd Smale]

personaly im building one myself and it will be a heavy stainless 20 inch 1in9 twist barrel. if you are perdominantly just long range shooting a 1 in 8 may be a better choise. But i have one for that and this one will be for varmits only and i want vilolent expansion and that means 45-55 grain bullets and a 1 in 9 is a better bet for them. My long range gun has a 1 in 7 twist and it rarely shoot anything lighter then 60s in it alothough it does fine with 55s. Anything lighter just doesnt shoot in it.

[jtech]

Thanks to all for the input.
I'm thinking in the 60-70 gr. range, this gun will be strictly for target shooting.
I want to buy a Colt so I guess it will be a 20 in. 1 in 9. Would probably like a 1 in 7 but I'm guessing it's not worth giving up 4 in. of barrell for my intended use.Hopefully out to 600 yds. Local club is building a 1000 yd. range but I'm not sure a 5.56 is capable at that range? Would be fun to try! Have shot a A1 out to 400 meters with good results. Faster twist and heavier bullet should be a improvment. I like shorter barrells for defense also, my primary is a 4 in. 1911 with a youth model Win. 1300 backup.

[sk330lc]

If your talking 1000 Yards Go with the 1-7 and 69gr to 80gr Bullets .

[Arier Blut]

Berger bullets will get you out to 1000.
1-9 70 gr match vld
1-8 80 gr match vld
1-7 90 gr match vld

Just varying degrees of wind resistance. You may have a gander at this if you are thinking Colt.
http://www.coltsmfg.com/cmci/Accurized.asp
If you are looking strictly for target the front sight can blur a scope if it's magnified very much.
Good Luck