AR .308 NooB's 1st attempt at a precision rifle build.

BK.RD.RNR · October 29, 2017

Hello all,

I am starting out with a 5D Tactical 80% DPMS Gen 1 billet lower. I also intend to order one of their billet uppers.

I'd like to be able to run 7.62 and .308 so that I have the option of surplus ammo for everyday economy, and also be able to have my choice of match grade ammo when the mood strikes me (and the budget allows).

I am not very concerned with weight savings as the rifle will probably only go from the trunk to the bench most of the time. I can always build another carbine length upper for it down the road.

I think that I'd like to go with a match grade 20" bull barrell, rifle length gas system, target crown, and a threaded end so that I can install a muzzle break down the road if I want. I saw that Shilden barrells come with a headspaced bolt, but they look a little spendy... Not sure what the best value is there..

I'm not sure what the best value is for a bolt carrier/ assembly either.

I'd like a rifle length extension tube, and I think I'd like the heavier buffer (reduces felt recoil?).

I have some lower receiver internal parts from my AR15 builds (including a 2 stage (3#/1# break) Gisselle trigger group), but I am not sure what parts cross over.

If someone has a link to an easy to understand table of parts that will crossover between the AR15/10 platforms, that would be very helpful for me.

Also a guide to what parts are specific to the DPMS Gen1 and not compatible from other 308 platforms, and how to tell the difference when ordering with limited descriptions would be great too.

Any input, comments, suggestions, and links would be greatly appreciated. Also, if some of my statements are contradictory, corrections or clarifications would also be welcomed.

Although it may progress a little slowly, especially at first, I am really excited about this build, and learning as much as possible from the wealth of knowledge you all have compiled here.

Sorry if this is a little long winded, and thanks in advance for any guidance/ suggestions.

BK.RD.RNR · October 29, 2017

... Also wondering what AR.308 specific tools I might need for this build.

I have an AR15 armorers kit already.

Robocop1051 · October 29, 2017

The greater amount of your accuracy comes from your barrel, and then you’re trigger. Don’t skimp on those. Luckily parts are nowhere near as expensive as they used to be, for good quality.

Rifle and Carbine buffer systems are equally effective. Pick furniture you like, and build up from there. My personal target rifle used a Carbine length system with a fixed stock. I’m not very tall and I prefer compact formats.

BK.RD.RNR · October 29, 2017

Thanks for the reply.

I'm over 6' tall and will probably go with the longest furniture options that I can find. Hopefully with some adjustability to the stock.

Any suggestions for match grade barrell manufacturers? I am not married to the 20" barrell idea, but from looking at the charts, it does not seem there is a big gain in performance going to a 22 or 24".

edgecrusher · October 29, 2017

Typically there isn’t much to gain from 20”, but there will be some gains, if accuracy is your utmost goal and weight isn’t an issue. Keep in my mind your limitations. We don’t know you so don’t be insulted but you can build something far greater than you can reach for accuracy limits. If you have a precision rifle that can do 5 shot groups at .5 moa but you can only shoot 1.5 moa, no part in the world can fix that. I have had one day where I got .375” out of my OBR but have repeated it in YEARS! I’m typically a .75” group. I know the rifle can do it, I’ve done it, but I also know I have been getting the trigger time lately. Just food for thought.

98Z5V · October 29, 2017

If I were buiding that rifle right now, I would use one of these barrels, and wouldn't be considering anything else but one of these 3...

Look at the ".308 AR Fulton Armory Barrels" here, from Criterion Barrels:

http://criterionbarrels.com/barrels/.308_AR

Look at the "AR.308 Premium Series" here, from Ballistic Advantage:

http://ballisticadvantage.com/ar-parts/ar-barrels/ar308/premium-series

Look at the "Match Series" selections on this page, here, from Faxon Firearms:

http://faxonfirearms.com/barrels/ar-10-lr-308/308-winchester-7-62-nato/

Any of the barrels from those 3 manufacturers will definitely get the job done. Over the herd of gear that I have, I have barrels from all 3 manufacturers, and they're all great barrels.

98Z5V · October 29, 2017

11 hours ago, BK.RD.RNR said:

... Also wondering what AR.308 specific tools I might need for this build.

I have an AR15 armorers kit already.

You pretty much have it covered, then. The only major, major differences between the two, as far as tools go, are whatever rail or handguard you buy for the big one, the armorer's wrench for the AR-15 probably isn't gonna fit the new barrel nut. Most higher quality handguard kits come with the appropriate barrel nut adapter or wrench, though. The muzzle device slot in the armorer's wrench won't fit the flats on a .30-cal muzzle device. Everything else shouldn't be an issue.

You're in New York, right? Check into that batch of stupid new laws your awesome representatives voted in. Don't build something that's gonna get you turned into a Felon.

BK.RD.RNR · October 30, 2017

9 hours ago, edgecrusher said:

Typically there isn’t much to gain from 20”, but there will be some gains, if accuracy is your utmost goal and weight isn’t an issue. Keep in my mind your limitations. We don’t know you so don’t be insulted but you can build something far greater than you can reach for accuracy limits. If you have a precision rifle that can do 5 shot groups at .5 moa but you can only shoot 1.5 moa, no part in the world can fix that. I have had one day where I got .375” out of my OBR but have repeated it in YEARS! I’m typically a .75” group. I know the rifle can do it, I’ve done it, but I also know I have been getting the trigger time lately. Just food for thought.

Thanks again for the replies.

No offense taken. I agree wholeheartedly. I am fairly competent with a rifle at 100 - 200 yards. It's fun getting razzed by the other guys at the range when I hit the 200yd 5" steel plate with my 22LR, the .223 isn't much of a challenge anymore. I really don't have any experience to speak of at much longer range, but I'd like to start getting into the 3-500yd range, and maybe more if I find that I have a knack for it.

I figure if I'm going to spend the money, building it beyond my known capability doesn't cost much more, and at least I'll know that it's me running out of talent, and no fault of the equipment.

98Z5V · October 30, 2017

That's a good plan, right there. :thumbup:

BK.RD.RNR · October 30, 2017

8 hours ago, 98Z5V said:

You pretty much have it covered, then. The only major, major differences between the two, as far as tools go, are whatever rail or handguard you buy for the big one, the armorer's wrench for the AR-15 probably isn't gonna fit the new barrel nut. Most higher quality handguard kits come with the appropriate barrel nut adapter or wrench, though. The muzzle device slot in the armorer's wrench won't fit the flats on a .30-cal muzzle device. Everything else shouldn't be an issue.

You're in New York, right? Check into that batch of stupid new laws your awesome representatives voted in. Don't build something that's gonna get you turned into a Felon.

Thank you for tool info and barrell links. I had checked out the BA barrells already, and I'll check out the others you recommended too.

All of my rifles have 10 round fixed magazines, fixed stocks, and long barrels, so I should be good. ... Yeah, the only good thing about the new laws is that it saves me a lot of money. I would definitely burn through WAAAAY more ammo with large cap mags.

98Z5V · October 30, 2017

Review this one - even thought there's no real info there on building.

https://safeact.ny.gov/

Here are details on it that you won't find in that "official website" I linked above:

https://en.wikipedia.org/wiki/NY_SAFE_Act

Threaded barrel - are you good, OP? You can have threaded barrels in that state now?

BK.RD.RNR · October 30, 2017

I did get the lower milled out today. It came out very nicely I think, with one exception. The left side hole for the safety selector is a little ovalled out. Entirely my fault for not watching the instruction video for an extra 30 seconds before drilling.

Do you guys think it is a fatal flaw, or will it just depend on how bad it is? I am convinced it will allow for a slight wobble to the switch, but not sure if it will affect functionality at all.

I can build it out and do a function check, but if someone with more experience knows it won't work properly, I won't invest the time.

I'll try to post a few pictures..

98Z5V · October 30, 2017

SAFE ACT details:

BK.RD.RNR · October 30, 2017

BK.RD.RNR · October 30, 2017

16 minutes ago, 98Z5V said:

SAFE ACT details:

My magazines are not detachable. There is a kit which permanently disables the magazine release, you use an easy pull takedown pin to open the the rifle, and hand load the (now) fixed magazine.

98Z5V · October 30, 2017

I didn't think that "feature" negated all the other things that they put into law. I might be very wrong on that. Not slamming you, personally, but you'd have more "free" AR legislation against you if you lived in California. No kidding.

BK.RD.RNR · October 30, 2017

No worries. If you read from the picture/ screenshot you posted, it clearly states "a semiautomatic rifle that has the ability to accept detachable magazines AND has at least one of the following characteristics" .

As explained to me by the guys at my local gun shop who have a very large selection of EBRs, and an attorney on retainer to make sure they are compliant, as long as your magazine is fixed, you are permitted up to three of those other mentioned features. The one I am building may have 2 at most.

I appreciate your concern, but I've sought out advice on the issue from more than a few of my local gun shops, have gotten consistent information from all of them, and am fairly confident that I am compliant with the law. .... I do wish I could convince my wife to move out of state though for sure. :thumbup:

98Z5V · October 30, 2017

16 minutes ago, BK.RD.RNR said:

No worries. If you read from the picture/ screenshot you posted, it clearly states "a semiautomatic rifle that has the ability to accept detachable magazines AND has at least one of the following characteristics" .

As explained to me by the guys at my local gun shop who have a very large selection of EBRs, and an attorney on retainer to make sure they are compliant, as long as your magazine is fixed, you are permitted up to three of those other mentioned features. The one I am building may have 2 at most.

I fully read it. I fully read it when those a$sholes passed it. I don't care what it "clearly states", or how some attorney explained it to you, as his interpretation.

I don't care about that.

I care about you- YOU - as a member of this board (now that you've joined), and asking build advice here. I don't care what you interpreted out of it, and I don't care what your attorney interpreted out of it - I care what the LAW in your state says "is the law."

You're her asking for build advice, and I don't live in your state, and I don't live under your state's bullshiit laws. Not many here do. Yet, you need advice from us.

I know for a fact that your state's law are more fucked up than California's gun laws - and that's hard to do. At least the members in California fight this, and have a pretty comprehensive flow-chart to deal with their BS gun laws - your state DOES NOT have that.

My bottom line is this - you, basically, are on your own. You're alone, with all other New Yorkers. No one here will turn their back on you, but no one here can advise you on about... anything.

If you wanna pin your mag, and think you're okay with threaded barrels - then you have at it. You're gambling on your own security here, and your own future.

If you wanna do something for New Yorkers, then develop something like this for them:

https://www.calguns.net/caawid/flowchart.pdf

survivalshop · October 30, 2017

10 hours ago, BK.RD.RNR said:

The left side hole for the safety selector is a little ovalled out. Entirely my fault for not watching the instruction video for an extra 30 seconds before drilling.

Do you guys think it is a fatal flaw, or will it just depend on how bad it is? I am convinced it will allow for a slight wobble to the switch, but not sure if it will affect functionality at all.

The Safety hole being oblong may or may not effect your Safety & how it engages , too much slop & it might effect it . Only way to know for sure is to assemble the Lower & test it . It doesn't look all that bad from the Photo , but hard to say from a photo .

BK.RD.RNR · October 30, 2017

7 minutes ago, survivalshop said:

The Safety hole being oblong may or may not effect your Safety & how it engages , too much slop & it might effect it . Only way to know for sure is to assemble the Lower & test it . It doesn't look all that bad from the Photo , but hard to say from a photo .

Thanks for the reply. I'll test it out tomorrow.

BK.RD.RNR · November 1, 2017

On 10/30/2017 at 8:02 AM, survivalshop said:

The Safety hole being oblong may or may not effect your Safety & how it engages , too much slop & it might effect it . Only way to know for sure is to assemble the Lower & test it . It doesn't look all that bad from the Photo , but hard to say from a photo .

Assembled the FCG this evening, everything is functioning properly. Time to put the parts list together!

Robocop1051 · November 1, 2017

If you have safety issues, it’s possible to patch aluminum and redrill the hole.

98Z5V · November 1, 2017

28 minutes ago, Robocop1051 said:

If you have safety issues, it’s possible to patch aluminum and redrill the hole.

Do it everyday at work. :thumbup:

Robocop1051 · November 1, 2017

12 hours ago, 98Z5V said:

Do it everyday at work.

Yeah. I’d drill out a 1” hole, then plug and re-drill. I suck at welding aluminum though. I’d probably just spot weld three or four spots, and call it even. Although, I believe the OP has some milling equipment/skill, so ugly welding can be covered up pretty easily.

BK.RD.RNR · November 1, 2017

13 hours ago, Robocop1051 said:

If you have safety issues, it’s possible to patch aluminum and redrill the hole.

I had considered that, but there seems to be no issue with functionality whatsoever. To have it "repaired" would only feed my anal retentive nature, offer no improvement to functionality, and would probably worsen the cosmetic situation. As it is the lip from the safety selector completely covers the imperfection. I am going to run with it, and never make that mistake again.