Got an AR .308 Lower, need to pick a barrel length and parts kit

[TheJoe90 27]

I purchased a .DPMS 308 lower, and now I need some input before I buy parts. This is, after all, my first AR. Im going to be focused on shots outside of 300 yards, kind of a "Jack of all trades, Master of none"

 

This weapon will have a mid power scope, designed to fill the gap between my AK and my Remington 700. I want to build an accurate, affordable, and maneuverable weapon.

 

I have heard a few folks say that 16 inch is too short to be realistic for a load as powerful as a .308, saying 20 is the shortest they would go.

 

Then, 2 mins later, someone says that the accuracy difference will be so small that there is no difference between them practically....

 

Someone told me that having a rifle gas system is better than a carbine gas system.... I dont know if that is true.

 

The kits I am looking at:

16 inch kit

20 inch kit

 

Im open to any constructive input.

 

PS: I will always love my AK and my S12 the best

[sccritterkiller 473]

I would go with 18"....16" is a little short for what you want to do but a 20" rifle will weigh so much it will be restricted to a bench rifle. IMHO

 

I have a 16" and I can ring the steel @ 300yds all day...I just have a eotech on mine....I hunt with it and a 300 yd shot is pushing it for any game...and most of my shots r 100 yds or less....I like to get in amongst the critters...

Edited April 13, 2013 by sccritterkiller

[tim2shu 48]

American spirit Arms

[RED333 1,025]

Ya gona get 10 or 20 good answers, my Saiga .308 in a bit over 18", shoots very well to 300 yrds, longest I have shot with it.

We have a CETME with a 20" barrel and a FNAR with a 22" barrel, all are great shooters.(piss off a deer with no worries)

Get what you want and work up a good load for the barrel.

[Dad2142Dad 6,559]

My S308 is 18" with the M60 FH, does very well at that range. 20" will get you farther out, but will have issues with weight and zombies in the house. If at all possible see if you can hold each one at a shop or store.

 

Please post pics of what the final outcome is

[semper299 284]

Just my 2 cents, but I would not Chrome line the barrel. unless u plan on shooting corrosive stuff. Between those two options, I would go with the 20 inch.

[mostholycerebus 415]

18" is optimal for .308 unless you are making really long shots.

[Bretonmaitre 36]

Joe, Welcome in advance to the AR-10 club. Heavy but good shooters. Now if we can just get some reasonably priced 308 ammo!

[Syndicate 812]

I would go 20, it's still pointable and you get the best use of range out of it for what it sounds like you are doing

[menace667 194]

For 600 yard shots and under 18" is optimal. Get a fluted barrel to reduce weight (it helps) and a light handguard if your concern is weight. I would also say, if your concern is weight i would look into the 6.8spc or 6.5 grendel if you already have the AR platform. Both are medium range and hard hotting rounds and are compatible with your current AR set up. Swap the upper and go. Their weight is the same as a standard AR and basically all the other parts are interchangeable.

[zaxon_182 44]

I agree with the above sentiments. I'd prefer an 18" but I'd go 20" over 16". I owned a DMPS LR308 AP4 and that girl had a nasty (fun) bark and could reach out to 500yds no problem.

 

From Arfcom:

 

150 gr HPBT Win 748 loaded to a chamber pressure of 56.4K PSI WARM load 45 gr NOT a starting load. I chose 748 as the powder as it is most like NATO powder.

26" = 2918 FPS MP= 6.6K PSI ––99.6 % powder burnt -2836 ft/lbs
24" = 2873 FPS MP= 7.4K PSI ––––––––––––––––––––––––––––2750 ft/lbs
22" = 2823 FPS MP= 8.2K PSI ––––––––––––––––––––––––––––2655 ft/lbs
20" = 2766 FPS MP= 9.2K PSI ––98.7 % powder burnt -2548 ft/lbs
18" = 2700 FPS MP= 10.5K PSI ––––––––––––––––––––––––––––2428 ft/lbs
16" = 2623 FPS MP= 12.0K PSI -97% powder burnt ––––2291 ft/lbs
14" = 2531 FPS MP= 14.0K PSI ––––––––––––––––––––––––––2133 ft/lbs
12" = 2417 FPS MP= 16.7K PSI -94% powder burnt ––1946 ft/lbs
10" = 2273 FPS MP= 20.5K PSI ––––––––––––––––––––––––––1721 ft/lbs
8.0"= 2080 FPS MP= 26.0K PSI -87% powder burnt. -1441 ft/lbs
6.0"= 1800 FPS MP= 34.1K PSI -79.4% powder burnt -1080 ft lbs

 

ETA: The thread pitch on the barrels in those parts kits are 1/2-28, which limits the muzzle devices you can use since a majority of the 308 muzzle threads/devices I've seen are 5/8-24.

Edited April 13, 2013 by delNbones

[Syndicate 812]

don't get fluting, barrel harmonics is much more important than people give it credit for and fluting and all those wacky cuts ruin barrel harmonics, my first ar10 was a 22 inch with wacky fluting (no idea what Tacticool name they gave it) wasn't as good as my 18 with a plain barrel and flash sup. Damned expensive ass barrel also.

[XD45 7,124]

I consider 18" to be the optimum length for a 308 battle rifle. (As others have said.)

 

But between 20 and 16 I would chose 20.

Edited April 13, 2013 by Darth Saigus

[TheJoe90 27]

My God I have received some amazing answers! Thanks yall, a lot of people who feel an 18 inch barrel is the cats meow on this platform.

 

Just my 2 cents, but I would not Chrome line the barrel. unless u plan on shooting corrosive stuff. Between those two options, I would go with the 20 inch.

 

I would really like an elaboration on this, why would you not want a chrome barrel?

 

My S308 is 18" with the M60 FH, does very well at that range. 20" will get you farther out, but will have issues with weight and zombies in the house. If at all possible see if you can hold each one at a shop or store.

 

Please post pics of what the final outcome is

 

If I had zombies in my home, Im not sure the AR would be my first choice! I think indoors I would reach for my .357 or S12.... Most likely shoot my roommate first for letting them in!

 

Joe, Welcome in advance to the AR-10 club. Heavy but good shooters. Now if we can just get some reasonably priced 308 ammo!

 

Thanks friend! I am stoked to be joining the club, Im amazed by how expensive parts are for this thing. Close to $100 for a 20 rd mag in this area!

 

Damn glad I load my own ammo.

 

For 600 yard shots and under 18" is optimal. Get a fluted barrel to reduce weight (it helps) and a light handguard if your concern is weight. I would also say, if your concern is weight i would look into the 6.8spc or 6.5 grendel if you already have the AR platform. Both are medium range and hard hotting rounds and are compatible with your current AR set up. Swap the upper and go. Their weight is the same as a standard AR and basically all the other parts are interchangeable.

 

I had been considering fluted and "Bull Barrels" but Im having trouble finding them instock for reasonable prices.

 

Im sticking with the types of ammo I already have for now, so no 6.5 or 6.8 yet. Plus, dont those rounds use an AR-15 lower??

 

I agree with the above sentiments. I'd prefer an 18" but I'd go 20" over 16". I owned a DMPS LR308 AP4 and that girl had a nasty (fun) bark and could reach out to 500yds no problem.

 

From Arfcom:

 

150 gr HPBT Win 748 loaded to a chamber pressure of 56.4K PSI WARM load 45 gr NOT a starting load. I chose 748 as the powder as it is most like NATO powder.

26" = 2918 FPS MP= 6.6K PSI ––99.6 % powder burnt -2836 ft/lbs

24" = 2873 FPS MP= 7.4K PSI ––––––––––––––––––––––––––––2750 ft/lbs

22" = 2823 FPS MP= 8.2K PSI ––––––––––––––––––––––––––––2655 ft/lbs

20" = 2766 FPS MP= 9.2K PSI ––98.7 % powder burnt -2548 ft/lbs

18" = 2700 FPS MP= 10.5K PSI ––––––––––––––––––––––––––––2428 ft/lbs

16" = 2623 FPS MP= 12.0K PSI -97% powder burnt ––––2291 ft/lbs

14" = 2531 FPS MP= 14.0K PSI ––––––––––––––––––––––––––2133 ft/lbs

12" = 2417 FPS MP= 16.7K PSI -94% powder burnt ––1946 ft/lbs

10" = 2273 FPS MP= 20.5K PSI ––––––––––––––––––––––––––1721 ft/lbs

8.0"= 2080 FPS MP= 26.0K PSI -87% powder burnt. -1441 ft/lbs

6.0"= 1800 FPS MP= 34.1K PSI -79.4% powder burnt -1080 ft lbs

 

ETA: The thread pitch on the barrels are 1/2-28, which limits the muzzle devices you can use since a majority of the 308 muzzle threads/devices I've seen are 5/8-24.

 

You sir are a HERO! Thank you for posting this chart!

 

don't get fluting, barrel harmonics is much more important than people give it credit for and fluting and all those wacky cuts ruin barrel harmonics, my first ar10 was a 22 inch with wacky fluting (no idea what Tacticool name they gave it) wasn't as good as my 18 with a plain barrel and flash sup. Damned expensive ass barrel also.

 

Very interesting... I have not heard this before. I will have to do some research.

 

-------------------------------------------------------

 

So now that I have mostly decided on an 18 or 20 inch, I need to find a source for an affordable 18 inch barrel. Then I need to decide if I want the entire kit and to just swap my own barrel in, or if I want to create my own kit....

[nlacy 692]

I'd go with the 16"... because the 20' appears to be out of stock

[zaxon_182 44]

So now that I have mostly decided on an 18 or 20 inch, I need to find a source for an affordable 18 inch barrel. Then I need to decide if I want the entire kit and to just swap my own barrel in, or if I want to create my own kit....

 

I'd hazard to say that you are hard pressed to find a more economical parts kit. My current AR308 build will end up around $2k with glass and it will be my hunting rig.

 

I would check out Fulton Armory or Rainier Arms barrels. From what I've read, they both have sweet shooting barrels for DPMS type 308s. YMMV

Edited April 13, 2013 by delNbones

[TheJoe90 27]

So now that I have mostly decided on an 18 or 20 inch, I need to find a source for an affordable 18 inch barrel. Then I need to decide if I want the entire kit and to just swap my own barrel in, or if I want to create my own kit....

 

I'd hazard to say that you are hard pressed to find a more economical parts kit. My current AR308 build will end up around $2k with glass and it will be my hunting rig.

 

I would check out Fulton Armory or Rainier Arms barrels. From what I've read, they both have sweet shooting barrels for DPMS type 308s. YMMV

 

PERFECT! Thank you.

[Redhunter2486 22]

I picked up some .308 Prvi partizan from a tip on here about a month ago pretty cheap, surprised it shot a quarter group at 100yds

[TheJoe90 27]

Well, Looking at barrels and seeing how much I dont know once again...

 

If I were to buy the kit and later want to change the barrel... how hard will that be to do?

[Syndicate 812]

I'll see if I can dig up the 3 or 4 medium to damn that's long articles varying in scientific jargon and layman's also hehe

[menace667 194]

"Finally, to get to the actually discussion at hand, barrel harmonics occur regardless of the thickness of a rifle barrel. Even the thick match barrels flex and the mechanical system in the M14 contributing further to its strange harmonics, makes the M14 a bitch to keep and maintain as a competition or sniper rifle system. The same thing occurs with the FN SLR or LAR rifles. I'm sure it is because of the short or long stroke piston systems. With the AR design, everything is in line with the barrel and it uses a direct impingment system for recycling the bolt carrier system. All adding to the AR being an inherently more accurate rifle design. "

 

Best short post i could find about barrel harmonics. It is from an Army sniper who was in the 82nd (Airborne hooah).It does impact every single rifle made, regardless of type, to some point. It is essentially a barrel flexing during fire due to the forces being placed upon it by many different factors. those factors vary depending on the rifle type. an AK has much more flex than an AR does. Many do point out that the heavier barrel a rifle has, the less prone it is. They also point out the the AR platform is mechanically much less prone due to the fact that it is a fully jn line system that does not have nearly as much "violent" activity occuring inside it as many other battle rifles do, especially piston rifles.

 

<blockquote class='ipsBlockquote'data-author="TheJoe90" data-cid="889780" data-time="1365889599"><p>

Well, Looking at barrels and seeing how much I dont know once again... <br />

<br />

If I were to buy the kit and later want to change the barrel... how hard will that be to do?</p></blockquote>

 

If you build it yourself it is cake. All it will really require is removing the handguards and the barrel nut. If you build it you will have the specific tools for those parts. If you buy it preassembled it can be slightly more tricky because many manufacturers use proprietary tools so you will need to know what to get. The actual work itself is very simple.

 

If you get a chance go to youtube and there are videos that will walk you through it.

[Syndicate 812]

this is a great one http://www.varmintal.com/alite.htm

 

http://www.rifle-accuracy.com/harmonics.htm

 

http://www.shootingsoftware.com/barrel.htm

 

Videos

eh it's ok

 

Here is the article that got me tracking down more info on harmonics

http://www.gunsamerica.com/blog/extreme-accuracy-makeover-the-teludyne-tti-tech-straightjacket/

 

long movie haven't watched yet, but was rated well http://www.howtomakeonline.org/MeVksMoneyVy704h/comments.html

[VR762Shooter 838]

Thanks friend! I am stoked to be joining the club, Im amazed by how expensive parts are for this thing. Close to $100 for a 20 rd mag in this area!

Damn glad I load my own ammo.

 

That's one of the reasons I went with a S308 when I got mine. Looking at price to performance, since I wasn't planning to be shooting sparrows from 1000yds, I went with the cheaper option. S308 mags can be had for cheap compared to a 308 Stoner. I chose to vote the 20", simply for the fact it will burn more powder and get you closer to optimal ballistics than a 16". Congrats on your purchase and hope everyone here can help ya with the barrel stuff

Edited April 14, 2013 by VR6Shooter

[Big John! 2,062]

I've been told that non chrome lined barrels will greatly benifit from a long thorough break in process. Is this fact or overkill? I watched a guy at the range firing a shot about every half hour and went through what seemed like 50 patches in that time. I thought he was just being meticulous until this was explained to me by someone else.

 

While I'm obviously no authority on this by any means and am actually learning a lot from this thread. Wouldn't a 20" give you the optimal results from a gun like this since I really wouldn't consider a 308 my go to gun for close quarters anyhow?

[semper299 284]

Chrome lining is not a bad thing, and I have barrels that are Chrome lined. However, CL barrels are the least accurate at longer distances of the barrel options available.

[Syndicate 812]

I usually do 20 shots, very slow, run 5 or 6 patches, rest the gun, do it again. usually do this for 200 rounds. Read something about it when I got my first precision rifle, and asked a few people that knew more about guns than myself at the time, and they said it wasn't a bad idea.

I bring my .22 and some other guns while I do this

 

I got 20 round pmags for $14 a piece shipped off GB last summer. Have some steals I use also, but got those mainly from my dad in trade for ammo years ago.

[menace667 194]

<blockquote class='ipsBlockquote'data-author="Big John!" data-cid="890046" data-time="1365948979"><p>

I've been told that non chrome lined barrels will greatly benifit from a long thorough break in process. Is this fact or overkill? I watched a guy at the range firing a shot about every half hour and went through what seemed like 50 patches in that time. I thought he was just being meticulous until this was explained to me by someone else.<br />

<br />

<br />

While I'm obviously no authority on this by any means and am actually learning a lot from this thread. Wouldn't a 20" give you the optimal results from a gun like this since I really wouldn't consider a 308 my go to gun for close quarters anyhow?</p></blockquote>

 

That is a break in by one anal S.O.B. and absolutely unnecessary. It is either how he was taught or something he read. On a breakin you want to make sure that you do not heat the barrel with rapid fire as not to "temper" or warp it for precision purposes. Basically like a motorcycle. They run fast as hell but all manufacturers recommend to not gun them for the first five hindred miles so the engine can get used to being ran normally. Same concept.

 

We always did sets of 3-5, slow and meticulous, and measured grouping at the same time.

[Big John! 2,062]

The way it was explained to me was one shot, cool, patch and some cleaner that I can't remember. It was a very long process. He said it yielded him much tighter groups than that offered by the manufacturer.

Again, this is just something I was told by some old dude. I really was looking to see if anyone here had gone to that much detail on a non chrome barrel.

 

I tend to think like you menace. But, it also makes sense to me to break them in very slowly as these shots that are going ridiculous distances accurately would require a barrel that is in perfect condition. I think, haha...

[semper299 284]

DS Arms is a manufacturer of AR 15's and other similar rifles. This is an article from their site about breaking in a new barrel. Not saying I do this, because I don't, but this is what they suggest.

 

My process is much like what was explained earlier. I shoot slowly, usually 3-5 shots at a time. Check group, shoot some more. After around 20 rounds or so, I clean the barrel with very little effort. Run a wet patch or two, run a dry patch or two, then continue shooting. I only do this for about 100 rounds, then I consider my barrel broken in. I only do this if the barrel is not chrome lined. If it is chrome lined, then I just shoot slowly for the first 100 rounds or so, but I don't clean it until after I am done.

 

Here is the link ot the article I mentioned.

 

http://www.dsarms.com/brebarrel.asp

[storm6490 2,768]

this will make you shit a brick..... http://proofresearch.com/barrels/