D.R.D. Posted October 3, 2013 Report Share Posted October 3, 2013 I've read much about how stiffer, heavier barrels decrease vibration, and can help accuracy. I've heard that a longer barrel will usually increase velocity, helping with shots at longer distances. We know it takes longer for a thicker barrel to heat up, and it can dissipate heat quicker due to more surface area. Longer gas systems shoot softer, as do heavier buffers, decreasing overall movement of the weapon, possibly contributing to accuracy and precision. Well, I've got build I'm working on, and it looks like it will come out to about 11 or 12 lbs., give or take. It's purpose is for longer range work. That said. I'm not adverse to making it a lighter platform for other types of shooting as well. Will changes in the weight of the rifle negatively in the following areas affect the accuracy, if all else is equal (shooting at 1K with the same 175 SMK loads)? Replacing the bull-barrel with a standard contour Shortening the barrel to 18" Going from rifle to mid length gas system Changing the PRS rifle-length stock to a collapsible stock (like the Battlelink UBS) Going from rifle length heavy buffer to a carbine heavy buffer - to fit the collapsible stock) Here are the original build specs: · 20” Black Hole Weaponry Black Steel Bull Barrel, Threaded with Polygonal Rifling 1:11 Twist · Troy TRX Battlerail 12 / 13.8” or CMMG Mk3 15" · R&D MRAD Removable Muzzle Brake · Geissele SSA-E / SD-E / Hi-Speed DMR Trigger · Magpul 10 round P-Mag · Large-Frame Ergo Grip or Umbrella Grip 23 · Magpul PRS Stock · SI-Defense Billet Receivers · PRI Gas-Buster Charging Handle · Wilson Combat Adjustable Low-Profile Gas Block (.936”) · CMMG Lower Parts Kit · DPMS Upper Parts (forward assist, port cover & spring) · DPMS A1/A2 Buffer Tube · Heavy Buffer & Spring · SI Defense Phosphate BCG · Basic Slipstream Treatment by Crusader Weaponry (BCG, Buffer, Spring & CH) · Harris HBMR 6-9" swivel-notch or Atlas Bipod · ADM QD Bipod Mount · ADM Scout One-Piece QD or Burris AR-PEPR Optic Mount SWFA Super Sniper 3-15x42 FFP MilDot Reticle, Butler Caps & Sun Shade Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted October 3, 2013 Report Share Posted October 3, 2013 A bull 18" barrel is more rigid than a bull 20" barrel. At that length, you will only lose about 60-100 fps depending on the load/bullet. I personally have 17" carbon fiber heavy-contour barrel. Fluting will help decrease weight, add surface area for cooling, as well as (arguably) add rigidity to the barrel. Quote Link to comment Share on other sites More sharing options...
D.R.D. Posted October 3, 2013 Author Report Share Posted October 3, 2013 What is this carbon fiber barrel you have? Quote Link to comment Share on other sites More sharing options...
edgecrusher Posted October 4, 2013 Report Share Posted October 4, 2013 Hah, the holy grail.... Good luck, he waited 17 months for and had to learn how to walk on water Quote Link to comment Share on other sites More sharing options...
BLKSHEEP Posted October 4, 2013 Report Share Posted October 4, 2013 We know it takes longer for a thicker barrel to heat up, and it can dissipate heat quicker due to more surface area. I have always been under the impression that it takes longer for a thicker barrel to heat up and also longer for it to cool down? I've been wrong once before so someone please enlighten me :)) Quote Link to comment Share on other sites More sharing options...
D.R.D. Posted October 4, 2013 Author Report Share Posted October 4, 2013 (edited) I think you are correct. Its just that with fluting, the theory is, that it increases surface area to a thicker barrel that would have taken longer to cool down with out fluting. Or so ive heard. So...whats the deal with this holy carbon barrel of the gods? Edited October 4, 2013 by D.R.D. Quote Link to comment Share on other sites More sharing options...
D.R.D. Posted October 4, 2013 Author Report Share Posted October 4, 2013 (edited) Found this: "Fluting a rifle barrel makes such a small difference in cooling that it is difficult to measure. The heat transfer coefficient of an object determines how fast it cools. For a rifle barrel you can use the formula for heat transfer coefficient of pipe wall. hwall = 2k/diln(do/di) where k is the thermal coefficient of the material, di is the inside diameter of the barrel, and do is the outside diameter of the barrel. If you double the outside diameter of the barrel you will have 8 times the surface area on the outside, but no change on the inside. This formula tells us that doubling the outside diameter of the barrel gives you a heat transfer coefficient only 1.3 times greater. Therefore an 800% increase in surface area gives a 30% increase in cooling. Fluting only slightly increases the surface area of the barrel. As for stiffness, fluting does make the barrel more rigid than a barrel with the same minor diameter but less rigid than a barrel with the same diameter as the major diameter. A fluted barrel will be very slightly more rigid that a barrel of the same mass. Fluting is a way to reduce the weight of the barrel while having the barrel slightly more rigid than simply reducing the diameter by turning the barrel down. Realistically, fluting is more for looks than anything else." http://www.snipercountry.com/articles/realbenefitsbarrelfluting.asp Edited October 4, 2013 by D.R.D. Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted October 4, 2013 Report Share Posted October 4, 2013 ProofResearch.com If you call, ask for Jeff Badelt or Mike Dagerness. They did a beautiful job on my barrel, but the waiting line is quite considerable (as was the price). You can see my build here. Quote Link to comment Share on other sites More sharing options...
D.R.D. Posted October 4, 2013 Author Report Share Posted October 4, 2013 Nice . what do those barrels set you back? Back to the original questions....will gas length systems or buffer size/weight affect accuracy? Quote Link to comment Share on other sites More sharing options...
98Z5V Posted October 4, 2013 Report Share Posted October 4, 2013 (edited) ....will gas length systems or buffer size/weight affect accuracy? No. EDIT: However, research the reason for the manufacture of the Tubb CWS. It explains lock time. Edited October 4, 2013 by 98Z5V Quote Link to comment Share on other sites More sharing options...
Robocop1051 Posted October 4, 2013 Report Share Posted October 4, 2013 Nice . what do those barrels set you back? $900-$1k, depending on options and manufacturer. Quote Link to comment Share on other sites More sharing options...
D.R.D. Posted October 4, 2013 Author Report Share Posted October 4, 2013 Robocop, Ouch. Enjoy! 98zv5, How does the Tubb CWS differ from just running a heavier buffer? Quote Link to comment Share on other sites More sharing options...
Matt.Cross Posted October 4, 2013 Report Share Posted October 4, 2013 Robocop, Ouch. Enjoy! 98zv5, How does the Tubb CWS differ from just running a heavier buffer? If I'm not mistaken, the CWS weights are adjustable, whereas the heavy buffers are a single weight. Quote Link to comment Share on other sites More sharing options...
98Z5V Posted October 5, 2013 Report Share Posted October 5, 2013 Also adds 80-thou to the length of the carrier - in some rifles, this is required. Quote Link to comment Share on other sites More sharing options...
survivalshop Posted October 6, 2013 Report Share Posted October 6, 2013 Rifle length gas system will add velocity to projectile compared to Mid & Carbine systems . Helps for long range shots , because you want every FPS you can get , of course . As far as how accurate each system will be compared to one or other , well that would be hard to tell ,being that two like barrels will shoot probably different any way, so it would be hard to compare . I was always lead to believe that shorter heavy barrels shoot better , but when talking long range , you have to make compromises .I wish I could tell you the comparison between my FA 16" to my FA 20" HB's but I have never put a scope on the 16"HB & have no plans to do so . I like the MBUS on her . Both barrels have rifle length gas systems . Quote Link to comment Share on other sites More sharing options...
D.R.D. Posted October 6, 2013 Author Report Share Posted October 6, 2013 Thanks survivalshop, ...too bad you dont have a qd system on your scope to switch over to your 16", and give that side by side experiment a go! Quote Link to comment Share on other sites More sharing options...
survivalshop Posted October 7, 2013 Report Share Posted October 7, 2013 (edited) Thanks survivalshop, ...too bad you dont have a qd system on your scope to switch over to your 16", and give that side by side experiment a go! I've thought about it & may some day put a scope on the 16", just to see how they compare . There is some Chronograph results I did in the thread below this one, about short barrels & the FPS differences from the two bbl's. Edited October 7, 2013 by survivalshop Quote Link to comment Share on other sites More sharing options...
98Z5V Posted October 7, 2013 Report Share Posted October 7, 2013 Thanks survivalshop, ...too bad you dont have a qd system on your scope to switch over to your 16", and give that side by side experiment a go! It's more difficult than that. Just having QD scope mounts doesn't mean you can switch scopes from one rifle to the other. The Zero for the second rifle would be far off. For the purposes of barrel comparison, and truly being curious about the accuracy of both barrels, it might be worth it to zero on one, re-zero for the second, and re-zero back to the original. Just to let somebody else know - it really wouldn't be worth it. This would be where you, OP, buy two barrels, a scope, and a good QD scope mount, and go through that process. At the end of that process, you put those results up here. Quote Link to comment Share on other sites More sharing options...
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