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Posted: 1/21/2010 6:30:41 AM EDT
| New guy here but been shooting & reloading since the 70's. I"ve been thinking about building myself an AR-15. I want something for mostly target shooting (100-200 yds) and plinking too. For this type of shooting which would be better siuted a 20" or 16" barrel? |
| My newbish opinion is that if you're only going to shoot out to 200 yards on the bench then you would get a bigger return in versatility by going with a 16" than the return in accuracy would be going with a 20". Only you can decide if that versatility is worth it to you, is there any chance you're going to be "running and gunning" (you mentioned "plinking"? If so, 16" it is. Always gonna be on the bench, maybe with a bipod mounted? 20" it is. |
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First welcome to the board!!
All other things being equal, a quality 20" barrel is not going to necessarily be more accurate than a quality 16" barrel. It will give you some higher muzzle velocities and some added weight to the rifle. I think either would suit your needs. Just remember, this stuff can be addicting, and this board can be hazardous to your bank account! If you can't decide how about a 18" barrel. (I've built 2 SPR’s and really like them.) |
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BCM 16" Midlength Govt. Profile or BCM 20" Govt. Profile are the choices IMHO.
The 20" will have more velocity, longer sight radius, slightly more weight and less noise while sacrificing some maneuverability. Many will say if you are only going to have one then get a 16". I say that if you are only going to have one then get a 20" Here is a pic of mine. 
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Quoted: Ugliest couch I've ever seen. No wonder you keep it outside near the JungleGym.BCM 16" Midlength Govt. Profile or BCM 20" Govt. Profile are the choices IMHO. The 20" will have more velocity, longer sight radius, slightly more weight and less noise while sacrificing some maneuverability. Many will say if you are only going to have one then get a 16". I say that if you are only going to have one then get a 20" Here is a pic of mine. http://i13.photobucket.com/albums/a282/glazer1972/P1090003.jpg  I've got the same thing in 5.45. I'm still not able to decide if I should cut it down to 16+ inches just to make it more comfortable for offhand shooting. Anything passed 16", my groups start to get wider too fast without a bench rest. I don't know if my shoulders will lit me shoot a long barrel anymore. |
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Thanks to all for the fast and great suggestions. All you guys with the 18" barrels, I didn't even think of that one.
Kito: Yea I will probably be mostly bench and bipod rest shooting. Mybe knocking over some steel targets too. My runnin & gunnin days are over so maneuverability isn't an issue. I don't think there is a range around here longer than 200yds may 300 but thats all I know of. Glazer: Really like your build, looks like a good shooter. Is that a free float barrel? Thanks again for all the responses. Glad I found this site, so much info my brain is swelling and my wallet is getting thiner. |
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I guess buy building you don't need it all at once. Should have asked this in my original post but, is there a relationship with twist rate and barrel length or is the relationship with twist rate and bullet weight? Twist rate is independent of barrel length. 1/7" will perform best with the lighter weight bullets and 1/9" will perform best with the heavier bullets. Since you're thinking longer ranges you may want to consider shooting the heavier stuff since it tends to be more stable at distance. There is also 1/8" for a nice middleground though I haven't seen a huge selection of barrels in that twist rate. |
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I guess buy building you don't need it all at once. Should have asked this in my original post but, is there a relationship with twist rate and barrel length or is the relationship with twist rate and bullet weight? Twist rate is independent of barrel length. 1/7" will perform best with the lighter weight bullets and 1/9" will perform best with the heavier bullets. Since you're thinking longer ranges you may want to consider shooting the heavier stuff since it tends to be more stable at distance. There is also 1/8" for a nice middleground though I haven't seen a huge selection of barrels in that twist rate. You have it backwards. 1/7 for heavier bullets. 1/9 for lighter bullets. |
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A 20" will give you more accuracy, better versatility in terms of the variety of loads and uses, including competitive service rifle, hunting, varmint, and home defense. Get at least a 1/9 twist. Faster twists will allow heavier bullets for longer distances and more downrange energy.
Roy |
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I guess buy building you don't need it all at once. Should have asked this in my original post but, is there a relationship with twist rate and barrel length or is the relationship with twist rate and bullet weight? Twist rate is independent of barrel length. 1/7" will perform best with the lighter weight bullets and 1/9" will perform best with the heavier bullets. Since you're thinking longer ranges you may want to consider shooting the heavier stuff since it tends to be more stable at distance. There is also 1/8" for a nice middleground though I haven't seen a huge selection of barrels in that twist rate. You have it backwards. 1/7 for heavier bullets. 1/9 for lighter bullets. Oh my, hasty typing. I knew that. Been going for over 40 hours, I should hit the hay!
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I started out with a 16" Hbar with carry handle. then I sold that and got an 16" SS bull barrel carbine with a scope and it shot pretty good. then I learned more about Ar's and I got a 11.5" to play around with and a 16" M4 for the longer range stuff. now I have sold both of those and I'm building an 18" SS mid weight rifle length gas system w a 13" larue rail and full magpul furniture. 18X leupold scope, larue mount, DTNC compensator and a Jewell trigger. should be one heck of a shooter.
if you plan to target shoot get the longest gas system you can fit on what ever barrel length you decide on. for 200 yrds you can use any barrel length you want. for 300-400 you would be better off with a 18-20 and beyond 400 you have the wrong bullet. lol. now a 6.5 grendel..... thats another story 
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For 200 yard and under shooting, wanting very good accuracy I think the 18" barrel is a good choice. I am not alone in this, I think you will find there is something called a "Mk12 SPR" in use by the military. It uses a 18 barrel for better accuracy. I, like many precision shooters, use the 1-8 twist as it seems to cover a wide range of bullets. In fact, the Sierra Match King 77 gr. target bullets I use clearly state on the box to use a "1 in 8 twist barrel".
The Mk 12 is an HBAR configuration. Normally used with a Free Float handguard. Some searching will turn up all sorts of info on it. |
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I also went through a barrel delima a few weeks ago. Read some impressive performance from a 18" DPMS SASS. Decided it would be a good fit for what I was trying to put together. 18" SS (black) Bull, Fluted , threaded, 1/8 twist, mid gas sys. A little on the heavy side but certainly not more than a high power hunting rifle plus I dont plan on carrying this around for hours on end. Have yet to get it out to range.
Go with your gut, you know more of its intended use. Good Luck |
| Thanks for all the great input. Looks like 18-20 will be the choice length. I had a 3 shot burst m-16 I shot regularly in guard. They gave us a lot of tracer to burn up at times and as most you guys know nothing get a gun messier than tracer ammo. I'm also a Navy VietNam vet from the gulf of Tonkin but we only qualified with 1911, obviously one of my favorite weapons. |
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I guess buy building you don't need it all at once. Should have asked this in my original post but, is there a relationship with twist rate and barrel length or is the relationship with twist rate and bullet weight? Twist rate is independent of barrel length. 1/7" will perform best with the lighter weight bullets and 1/9" will perform best with the heavier bullets. Since you're thinking longer ranges you may want to consider shooting the heavier stuff since it tends to be more stable at distance. There is also 1/8" for a nice middleground though I haven't seen a huge selection of barrels in that twist rate. You have it backwards. 1/7 for heavier bullets. 1/9 for lighter bullets. Oh my, hasty typing. I knew that. Been going for over 40 hours, I should hit the hay!
That reminds me of a line from Lord of the Rings, "Don't be hasty!"
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