saibot Posted July 15, 2011 Share Posted July 15, 2011 Unless you really need the little FPS that the longer barrel affords you, I'd go with the lightest 16" you can. Having all of the weight out front really makes a difference in handling and balance. I'd shoot less if I didn't have to pay $200 to do so. My 2 cents. Link to comment Share on other sites More sharing options...
MickB Posted July 15, 2011 Share Posted July 15, 2011 (edited) Dwell time is the time the bullet is in the barrel right after it passes the gas port. Think of it as the time that the gas system has available to operate under pressure. The AR15 was optimized for a 20" barrel. When the carbines were first developed, they had very little barrel in front of the gas port and there were all sorts of problems. Basically not enough operating (dwell) time, so they opened up the gas port to compensate which led to a more violent, overgassed action. The engineers at Colt kept increasing the length of barrel to improve the reliability. What you have with the M4 14.5" barrel is the same length of barrel infront of the gas port as on the 20" rifle. So, in a 16" barrel, Armalite (Mark Westrom) developed the mid length gas system, keeping the same amount of barrel in front of the gas port as on a 20" rifle. Noveske has done the same with the 18" barrel and the "intermediate length" gas system. That's the short version, but I'm sure someone else will chime in... Mick I have two of Noveske's 18" barrels. One SPR profile, the other the lightweight profile. The lightweight is definitely easier to swing around. Recoil impulse is also no different to a 20" with full length gas system from what I can perceive. The reason for the "intermediate" gas system is to keep the same length of of barrel forward of the gas port as found on the rifle gas system in order to maintain the same dwell time. Noveske says they do this to maintain reliability.... Mick hmmmmm, i have heard the term dwell time used frequently to confuse idiots like me. where can i read more about this dwelling? Edited July 15, 2011 by MickB Link to comment Share on other sites More sharing options...
bagdrag Posted July 15, 2011 Share Posted July 15, 2011 Now I'm left wondering if there have been enough reliability issues with the rifle-length system on an 18" barrel to justify the intermediate length. Wouldn't a shorter barrel with a rifle-length system have a softer recoil impulse provided that reliability was not compromised? Or am I thinking of it backwards? Link to comment Share on other sites More sharing options...
CliffP Posted July 21, 2011 Share Posted July 21, 2011 18" is not an issue related to reliability. It is the choice of many top shooters that i have talked to. When you add a comp the balance and overall feel is good. I shoot a custom 18" carbon wrapped barrel with a rolling thunder comp and it works both for weight, accuracy and heat reduction. Link to comment Share on other sites More sharing options...
Alaskapopo Posted July 21, 2011 Share Posted July 21, 2011 Unless you really need the little FPS that the longer barrel affords you, I'd go with the lightest 16" you can. Having all of the weight out front really makes a difference in handling and balance. I'd shoot less if I didn't have to pay $200 to do so. My 2 cents. Balance is affected by the entire package. If you have a super light front and a heavy rear that is not good either. I really like the way my 18 inch Noveske Rogue hunter balances. Its balance point is right in the middle of the rifle or at least it feels like it. Its easy to move around. Pat Link to comment Share on other sites More sharing options...
bagdrag Posted July 22, 2011 Share Posted July 22, 2011 18" is not an issue related to reliability. It is the choice of many top shooters that i have talked to. When you add a comp the balance and overall feel is good. I shoot a custom 18" carbon wrapped barrel with a rolling thunder comp and it works both for weight, accuracy and heat reduction. I'm not talking about barrel length but about gas system length. Why does Noveske feel they need to advocate an intermediate-length gas system for their 18" barrels? Link to comment Share on other sites More sharing options...
Dan Sierpina Posted July 22, 2011 Share Posted July 22, 2011 I'm not talking about barrel length but about gas system length. Why does Noveske feel they need to advocate an intermediate-length gas system for their 18" barrels? They want to be different? Link to comment Share on other sites More sharing options...
bagdrag Posted July 22, 2011 Share Posted July 22, 2011 I'm not talking about barrel length but about gas system length. Why does Noveske feel they need to advocate an intermediate-length gas system for their 18" barrels? They want to be different? Fine by me. I run an 18" with rifle-length gas and zero problems. Link to comment Share on other sites More sharing options...
Alaskapopo Posted July 22, 2011 Share Posted July 22, 2011 18" is not an issue related to reliability. It is the choice of many top shooters that i have talked to. When you add a comp the balance and overall feel is good. I shoot a custom 18" carbon wrapped barrel with a rolling thunder comp and it works both for weight, accuracy and heat reduction. I'm not talking about barrel length but about gas system length. Why does Noveske feel they need to advocate an intermediate-length gas system for their 18" barrels? Noveske is about building reliable guns first and everything else comes after that. 18 inch barrels with a rifle gas system may work fine in most climates but in the cold we have here in Alaska they some times have issues. Pat Link to comment Share on other sites More sharing options...
bagdrag Posted July 22, 2011 Share Posted July 22, 2011 18" is not an issue related to reliability. It is the choice of many top shooters that i have talked to. When you add a comp the balance and overall feel is good. I shoot a custom 18" carbon wrapped barrel with a rolling thunder comp and it works both for weight, accuracy and heat reduction. I'm not talking about barrel length but about gas system length. Why does Noveske feel they need to advocate an intermediate-length gas system for their 18" barrels? Noveske is about building reliable guns first and everything else comes after that. 18 inch barrels with a rifle gas system may work fine in most climates but in the cold we have here in Alaska they some times have issues. Pat Well that makes sense. Thanks. Link to comment Share on other sites More sharing options...
krayons Posted July 26, 2011 Share Posted July 26, 2011 Thanks for posting that pic Pat. Going for a build like that. Got the 18" noveske light weight, just need a 15" TRX rail. May got PRI but starting to run low on funds. Link to comment Share on other sites More sharing options...
Daniel Riordan Posted August 3, 2011 Share Posted August 3, 2011 Either Noveske or Jp Custom for a new AR barrel cant be beat. Link to comment Share on other sites More sharing options...
Hamma Slamma Posted August 8, 2011 Share Posted August 8, 2011 I know everyone says the chrome lined barrels are not as accurate. How much "inacurate" are we talking about? At 300 yards would you lose 1/2", or would you lose 3"? For example, my buddy's got a Colt H bar that I am pretty sure is chrome lined 1:7, I have a DPMS I know for sure is not chrome lined 1:9... The 1:7 is far more accurate than the 1:9 shooting just about every ammo we threw at them. I'm wondering if I am splitting hairs worrying about the barrel being chrome lined. Will it really affect my accuracy "that" much? Just trying to get some kind of number I can quantify to aid in making a decision on this new build I am putting together for 3gun. I'm trying to find a balance of value and quality. I don't want to necessarily go cheap but my bank account isn't endless either. I had pretty much decided on a Daniel Defense s2w 18", 1:7, mid lenght until I saw it was chrome lined. https://danieldefense.com/cold-hammer-forged-barrels/18-5-56mm-s2w-mid-length-chf-barrel-stripped.html Everything I've ever read has said stay away from chrome lined... So now I really want to clear this up. Link to comment Share on other sites More sharing options...
MickB Posted August 9, 2011 Share Posted August 9, 2011 I have a recent build using a Colt 20" A2 1:7 government profile, chrome lined barrel. Has a Surefire brake, JP trigger, PRI hand guard. This combo was good enough to hit a 560 yard target using Winchester 55gr ball ammo with a Swaro 1-6. Same rifle and ammo with an Aimpoint PRO as the optic was good enough to hit the small plates at Rio Salado at 300 yards easily. So I would say good enough for our game, but each barrel might be a little different. Mick I know everyone says the chrome lined barrels are not as accurate. How much "inacurate" are we talking about? At 300 yards would you lose 1/2", or would you lose 3"? For example, my buddy's got a Colt H bar that I am pretty sure is chrome lined 1:7, I have a DPMS I know for sure is not chrome lined 1:9... The 1:7 is far more accurate than the 1:9 shooting just about every ammo we threw at them. I'm wondering if I am splitting hairs worrying about the barrel being chrome lined. Will it really affect my accuracy "that" much? Just trying to get some kind of number I can quantify to aid in making a decision on this new build I am putting together for 3gun. I'm trying to find a balance of value and quality. I don't want to necessarily go cheap but my bank account isn't endless either. I had pretty much decided on a Daniel Defense s2w 18", 1:7, mid lenght until I saw it was chrome lined. https://danieldefense.com/cold-hammer-forged-barrels/18-5-56mm-s2w-mid-length-chf-barrel-stripped.html Everything I've ever read has said stay away from chrome lined... So now I really want to clear this up. Link to comment Share on other sites More sharing options...
Alaskapopo Posted August 9, 2011 Share Posted August 9, 2011 I know everyone says the chrome lined barrels are not as accurate. How much "inacurate" are we talking about? At 300 yards would you lose 1/2", or would you lose 3"? For example, my buddy's got a Colt H bar that I am pretty sure is chrome lined 1:7, I have a DPMS I know for sure is not chrome lined 1:9... The 1:7 is far more accurate than the 1:9 shooting just about every ammo we threw at them. I'm wondering if I am splitting hairs worrying about the barrel being chrome lined. Will it really affect my accuracy "that" much? Just trying to get some kind of number I can quantify to aid in making a decision on this new build I am putting together for 3gun. I'm trying to find a balance of value and quality. I don't want to necessarily go cheap but my bank account isn't endless either. I had pretty much decided on a Daniel Defense s2w 18", 1:7, mid lenght until I saw it was chrome lined. https://danieldefense.com/cold-hammer-forged-barrels/18-5-56mm-s2w-mid-length-chf-barrel-stripped.html Everything I've ever read has said stay away from chrome lined... So now I really want to clear this up. Just a rule of thumb but a Stainless barrel can be as good as .5moa to 1.5 moa on average. A chrome lined gun can run from a good one being 1 moa to a bad one being 2.5. This is just based on my experience and nothing scientific. Pat Link to comment Share on other sites More sharing options...
Hamma Slamma Posted August 9, 2011 Share Posted August 9, 2011 (edited) Alaska thanks for the reply. Would you say this rule of thumb is fairly consistent among most major barrel manufacturers? I just can't afford spending $500 for a Noveske and am looking for the next best thing less than $300. Edited August 9, 2011 by Hamma Slamma Link to comment Share on other sites More sharing options...
Alaskapopo Posted August 10, 2011 Share Posted August 10, 2011 Alaska thanks for the reply. Would you say this rule of thumb is fairly consistent among most major barrel manufacturers? I just can't afford spending $500 for a Noveske and am looking for the next best thing less than $300. Try a Wilson barrel they seem to have good reviews. Pat Link to comment Share on other sites More sharing options...
mscott Posted August 10, 2011 Share Posted August 10, 2011 I have a Wilson and will buy another as it shoots a wide variety of ammo very well. Here's where I got mine http://jtdistributing.net/store/product1242.html. Link to comment Share on other sites More sharing options...
esskay Posted August 10, 2011 Share Posted August 10, 2011 Alaska thanks for the reply. Would you say this rule of thumb is fairly consistent among most major barrel manufacturers? I just can't afford spending $500 for a Noveske and am looking for the next best thing less than $300. Check out Nordic's offerings: http://shop.nordiccomp.com/Barrels-Bolt-Carrier-Assemblies-Gas-System-Components_c16.htm Link to comment Share on other sites More sharing options...
Hamma Slamma Posted August 10, 2011 Share Posted August 10, 2011 Nordic only has 16" it seems. Link to comment Share on other sites More sharing options...
Hamma Slamma Posted August 10, 2011 Share Posted August 10, 2011 (edited) I have a Wilson and will buy another as it shoots a wide variety of ammo very well. Here's where I got mine http://jtdistributing.net/store/product1242.html.'>http://jtdistributing.net/store/product1242.html. link is broken has an extra . Fixed: http://jtdistributing.net/store/product1242.html Awww darn it's 1:8. I'm trying to find 1:7 if possible, though it's proving to be a hard task finding a moderately priced 1:7 in stainless. I'll do some more hunting when I have time. I'm sure 1:8 is adequate to my ability and I can find some factory ammo it'll like to eat. I'm probably just being too cheap and too anal. Edited August 10, 2011 by Hamma Slamma Link to comment Share on other sites More sharing options...
bagdrag Posted August 10, 2011 Share Posted August 10, 2011 Isn't 1:7 optimal for really heavy bullets? I though 1:8 is much more versatile. Link to comment Share on other sites More sharing options...
mscott Posted August 11, 2011 Share Posted August 11, 2011 My 8 twist shoots the 77gr SMKs very well, but I still just use 55s and 69s. I don't see a need for a 7 twist in a 3 gun rifle. Link to comment Share on other sites More sharing options...
Alaskapopo Posted August 11, 2011 Share Posted August 11, 2011 1/8 is about perfection as far as twist rates go. 1/7 was designed to stabalize the long military tracer load. The 1/8 will work on bullets as heavy as 80 grains. I like my 1/7 Noveske but the 1/8 barrel on my Larue works slightly better with heavier bullets. (go figure) Pat Link to comment Share on other sites More sharing options...
kurtm Posted August 11, 2011 Share Posted August 11, 2011 Right on Pat!!!! The 1X7 was ONLY for the tracer round, as a matter of fact, the SS-109 round was designed for the 1X9 twist! 1X8 does more than enough and a lot of 1X9 barrels do just fine with 77 grain bullets. I have found that most barrels depend on throat lead, more than twist, when it gets this close. KurtM Link to comment Share on other sites More sharing options...
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