In The Process of Building A Designated Marksman AR-15, Need Tips

[Blackbird71SR]

Hello all. This is my first post, so please correct me if I’m in the wrong forum, or using a poor post structure.

So, I recently purchased an AR-15 lower, and decided that the niche I’d like to fill with it is that of a precision rifle with at least 500-yard capabilities.

So far, my intent is to build a flat-top, A4-style upper, with a heavy barrel. I’m thinking I want a 20”free-floating fluted HBAR with a 1:7 twist and 5R groove, but given that I’m quite unfamiliar with specifics, I’m trying to decide what material I’d like (Stainless or Chrome Moly), and if I’m even correct in the specifics I already think I want. My intent is to run it chambered in .223 Remington (given that my sole purpose for the rifle will be long-range precision, I’m not planning on firing much 5.56 out of it). I’m also curious what contour (outside of it being HBAR) would be best for a build like this. I’m not sure if it has any bearing on the barrel, but I’m also looking to do a 15-inch free float tube, and a rifle length gas system.

On top of what specifically I want to do with the barrel, I also need to find one in whatever specifications I do, so I was wondering if anyone had recommendations on custom barrel manufacturers, or pre-fab barrels that will fit whatever I decide.

And, just for the record, I’m also planning on installing a Giessele(?) SSA trigger, and was curious how y’all felt about them.

Thank you in advance!

 

[338dude]

That’s a project I’m looking to start for myself as well although I cannot be any help to you I will be following this thread

 

[rbutcher]

Get your barrel chambered in 223 wylde if you don’t want to use a 556 chamber. That way you can shoot 556 if you want, but the Wylde is a very accurate chamber.

For precision, I would recommend the Geissele SSA-E over the SSA. I have had both and prefer the lighter stages in the SSA-E for when I need to make those longer shots. It’s just a mechanical advantage that gives me more of a margin of error. So unless you have an aversion to triggers that are light, I would look to that one.

You should absolutely free float the handguard because if you use a bipod, you do not want the loading of the bipod to shift your point of impact.

 

[slothlacrosse]

This thread and this one. Oh, this one, too. Found another. And another. And one more

 

[PBWalsh]

Call White Oak Armory and Compass Lake Engineering. Either company has a stellar reputation for putting together high quality AR uppers and are going to have an extremely high knowledge base. @padom on here has also built several accurate AR platforms.

For a less expensive trigger option, take a look at the Larue MBT-2S. Mine is very crisp and weighted nicely, though I’d still like to try a Geissele HSNM.

I’m sure others will state the same, but get a thicker upper receiver such as the Vltor MUR. Stainless seems to be a better bet. Bartlien, Krieger, etc. cut in a quality shot will produce an accurate rifle.

Focus on barrel, trigger, and the upper receiver. Some will say a matched, headspaced bolt will help. Get a handguard with a stiff barrel nut connection. Geissele handguards are kinda known for this. A monolithic rail would be better, but there are not too many of them.

 

[BoulderE89]

As someone who’s tried this many times and finally succeeded with a great spr build after learning lessons on previous disappointments, I highly recommend white oak armory barrels. They’re very popular here and my attempts at saving money usually led to being disappointed. I have a 18” spr profile barrel that shoot sub moa. A quality barrel is the start to a great rifle.

also learned the hard way to make sure your gas block doesn’t walk on you, I blue loctite my set screws now.
Get a solid handguard that doesn’t flex and contact your barrel. Ones with a steel barrel nut are often good at this. Brownells new wrenchman series seems like a good option for the money but there are many that will do the job.
On that same note, I learned to file down all my mlok hardware screws because it would also contact the barrel when the handguard would flex. That contact would always cause my groups to be inconsistent. Making the barrel truely free floating is key.
lastly, for what it’s worth, I would look an enhanced (SSA-E) geissele trigger for precision work. The lighter trigger break is less likely to pull your shot. They are very good triggers and break clean. The breaking profile of the enhanced versions of their triggers are intentionally crisper than their standard ones, which are more combat orientated.

enjoy building yours! Once you have a shooter it’s incredibly fun. My spr is easily my favorite ar I own and the one I most often shoot.

 

[deersniper]

I would get something you can shoot 556 out of so you can use mk262 plus stuff like Hornady SuperPerformance 556

I would go with a Seekins or Larue upper/hg that has the extra support for the hg

Then get a good barrel. Proof, craddock, keystone, woa, lots of good stuff out there. I would get a adjustable gas block also

I really like the Seekins SP3 handguard. The flat bottom is nice

 

[TheHorta]

I would get something you can shoot 556 out of so you can use mk262 plus stuff like Hornady SuperPerformance 556

I would go with a Seekins or Larue upper/hg that has the extra support for the hg

Then get a good barrel. Proof, craddock, keystone, woa, lots of good stuff out there. I would get a adjustable gas block also

I really like the Seekins SP3 handguard. The flat bottom is nice

View attachment 7358367

There’s a rodent sleeping next to your gun.

 

[deersniper]

There’s a rodent sleeping next to your gun.

Lol thanks I don’t think he’s gonna wake up though.

 

[codym]

I bought a complete rifle from compass lake. Used a Douglas barrel and cle chamber. Shoots the 77 smks well but there is still some other loads I want to try. CLE was awesome to work with, really great people and delivered what they promised on time.

 

[roostercogburn98]

Went with a Bartlein heavy service contour blank and had it cut to 18 inches and headapaced to a Seekins bolt(1:8;wylde), WOA competition barrel extension , aero upper and lower, Triggertech Frictionless two stage trigger, Badger unimount, and a Bushnell HDMRii 3-21x50 scope. Plan on shooting 77g smk for the most part.

 

[MontanaMan]

Lots of good advice & options, lots of personal preference.

But you really don't need a 20", overly heavy barrel for a 500 yd gun, unless that's just what you prefer..............a good mid-weight 18" SPR barrel around 32 oz or even a good 16" barrel from 28-32 oz will more than suffice. Carrying around heavy guns is not much fun for me except to the range bench & back.

This barrel will get you all the accuracy that you an use at 500 yards.........................

https://www.rainierarms.com/rainier...3-wylde-750-gas-block-3-gun-fluted-barrel-16/

So will the equivalent Criterion, Bartlein or Rock Creek barrel from Craddock Precision.

MM

 

[powdahound76]

I am in the process of ordering parts for the same.

Just need a stock, barrel, and a few odds and ends for the lower, but most of that is just preference vs need.

Im going with a WOA 16” SPR, mid gas, adjustable block.
Will talk to them and probably use their comp extension as rooster did above as well as a matched bolt.

 

[smoothy8500]

Another vote for WOA barrel. The Wylde chamber allows me to use 77gr and 80gr match ammo. Barrel headspaced no problem with a Brownell's BCG and the extension fit tight in a BCM upper. Rock River Arms NM two-stage trigger is crisp 4.5# and only $80. It's not a DMR, but it shoots well at 600yds.

 

[needham]

Im going with a WOA 16” SPR, mid gas, adjustable block.

do you know what that barrel weighs?

 

[Trigger Monkey]

2 1/2 pounds

 

[powdahound76]

Yes.
i also am looking at a couple other options they offer.
though I think that fits my bill pretty easy with no fuss.
gonna call WOA this week and order is the plan.

 

[needham]

Yes.
i also am looking at a couple other options they offer.
though I think that fits my bill pretty easy with no fuss.
gonna call WOA this week and order is the plan.

I love the white oaks I have had in the past. Some of the best SPR barrels out there.

I do wish they had more "normal" offerings, such as a 30ish oz 16 inch barrel.

I'm probably gonna call this week too, cause I need to get off my ass and finish 2 guns.

 

[powdahound76]

Well, it would be nice to build a walk around gun with a tad lighter barrel.
Though 40 oz is my beer size, so a few more curls and I should be more than fit enough to handle the extra 10 oz.

I guess if my rig is gonna be a bit hefty, i want it in the right places, just like my lady.

I think the idea is like a heavier bolt barrel, to wander less with heat like some lighter barrels tend to?
Go with a PROOF! just saw one on here with matched match grade bolt.

 

[roostercogburn98]

So the barrel showed up Saturday. It looks good and weighs 2.1 pounds. I have it back together on the gun, but have yet to shoot it to see how it does.