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Posted: 2/23/2008 5:03:52 AM EDT
| I'm new to ARs, and am building my first one after having done a great deal of research. However, I am trying to choose the right barrel. Most of them say something like '1 in 9"'. What does this mean? Right now I'm looking at one with '1 in 8"'. Is this better? Help? |
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1 in 9" means that you get one Complete Rotation in 9" of your Barrel Which you need to know for Different Bullet weights, my Bushmaster is a 1 in 8" Twist Rate, I use my Bushmaster Predator to hunt Coyotes, and I use 55 Grn to 77 Grn Bullets. and I am prety sure that the faster the Twist, as in 1 in 7" is needed for heavier Bullets, my 1 in 8" Twist shoots REAL WELL for me in the Range of 45 Grn to 77 Grn Bullets. The Lighter the Bullet, the Faster the Twist is needed to Stabilize the Bullet IF I am wrong, someone on here will correct me, but I am pretty sure I am right? What Weight Bullet are you going to use? and what type of Shooting are you going to do which will dictate what type of Bullets you will be using? do you reload your own ammo ? are you going to be using Military Ammo, Commercial Ammo or are you going to Load your Own? I think the 1 in 8" barrel will suit all your needs in an AR-15, I could be wrong, and if I am wrong, someone will correct me and help you out Bob |
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My 1 in 8" Bushmaster shoots the Black Hills 77 Grn Sierra Match Hollow Points very well, it also shoots the Winnie White Box 45 Grn Hollow Points very well But I hunt Coyotes with 55 Grn Hand Loaded V-Max So you may want to pick a specific Bullet, what kind of AR-15 are you Building? |
| I'm not really sure what you mean by what kind. hopefully a good one? I'm putting together a .223 dpms lower, 24" 1 in 8" dpms upper, magpul prs stock, 3x9x40 scope, bipod, and a panther style grip. I want this specifically for long range. Any suggestions you have for any part of it would be HIGHLY appreciated. |
Actually, you've got it backwards. Heavier (longer) bullets require faster twist to stabilize them properly. FWIW, I consider 1:8 to be about ideal for someone who shoots 50- to 80-gr bullets. If you're going to exclusively use heavy bullets (75 to 90-grs) you'll want to go with 1:7. From what I've been able to gather, 1:7 barrels will sometimes shoot 50- to 55-gr bullets accurately, but sometimes won't, too. Depends on load and the individual barrel. OTOH, 1:9 barrels will work fine on 45- to 65-gr bullets, but won't adequately stabilize the heavier stuff. If you're wanting to shoot surplus M885 and M193 ammo, but still use heavier (75- to 80-gr) bullet loads, go with the 1:8. From what I hear, that's what virtually all long-range match shooters use. I'm no expert, but that's what I've been able to glean from my readings, and that's what I'll be putting in the ARs that I'm building. |
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