Need advice, critiques, and suggestions on plans for a precision .308

TexA-R · August 28, 2014

If anyone with more experience than me can chime in wIth suggestions or advice I would greatly appreciate it. This is my first A-R build and I want it to be put together using nothing but grade-A parts. My goal is to have a very accurate (>1 MOA) mid-long range capable for hunting and some target shooting. And also reliable. That's why I wish to use the best parts I can. But also knowing that I have to stick with one pattern in the upper.

This is my parts list as of now. Over the last 2 weeks I've changed it many times but I think I'm getting there. Please let me know if anyone has had issues or good results with anything listed.

MEGA MATEN Billet ambi lower and upper receiver

Lower already comes with bolt catch, takedown pins and charging handle

The Lower would contain the following

-Milspec magazine release and buffer retainer

-B.A.D. Short Throw Safety Selector

-Magpul UBR Buttstock

-Geissele SSA-E

-Hogue Ergo grip

-Undecided on buffer and buffer spring. I know it has to be a carbine buffer to go with the UBR. But I just don't know which one would work best with my gas system.

The upper will be made up of

-20 inch JP Match grade barrel with match grade bolt

-JP Low mass Bolt Carrier with BCG completion kit

-SLR .936 Sentry Adjustable Gas Block with Rifle length gas tube.

- Undecided on muzzle brake but have been looking at surefire. I just want something that helps the most with recoil

-Does anyone know of a dpms compatible free float handguard that is long enough to extend past a rifle length gas block but can still fit the slr gas block inside of it. (The block is 1.55 inches tall) will most handguards clear this block? Who makes the longest 308 handguard that is dpms compatible?

If anyone has any info that could help me out I would appreciate it. I'm trying to put this thing together soon. Thanks again.

D.R.D. · August 28, 2014

I think you'll probably want to use the JP buffer that matches the low mass carrier. ( or this one: http://www.midwayusa.com/product/549434/jp-enterprises-silent-captured-recoil-buffer-spring-ar-10-lr-308 )

And, I think Midwest Industries DPMS 308 15" handguards should work fine.

https://www.midwestindustriesinc.com/index.cfm?fuseaction=category.display&category_ID=1209

https://www.midwestindustriesinc.com/index.cfm?fuseaction=category.display&category_ID=1230

TexA-R · August 28, 2014

Thanks D.R.D. for the feedback. I looked at that buffer as well as some from heavybuffers.com. But just to play it safe I might go with the JP to keep my upper all the same. And do regular 15 inch handguards go past the gas block? I thought the gas port on the JP rifle length gas systems was 15.125 inches down the barrel.

Toolndie7 · August 28, 2014

May I suggest you consider a 16" barrel if you plan on doing any hunting, as a 20" may be a monster to tote around. You will still have exellent accuracy at longer distances. Also a JP recoil eliminator is exellent at reducing recoil with the down side of being extremely loud and rather big.

TexA-R · August 28, 2014

I've thought about but where I hunt, I'll never be walking or stalking. I'll always be in a tree stand or box blind. And I like knowing that I have the capability I'd making those really long shots. Whether it be at an animal or having fun with a target. I'm a pretty big guy. I hope the weight won't be that noticeable. If it is, I can always down grade. But I want to start with a 20.

And I don't believe I've seen that brake. I'll Look into it.

I like the surefires because they can be used with a can. Which I plan on getting in the future.

Robocop1051 · August 28, 2014

Since this is intended to be a target/hunting rifle...

• Ditch the 20" for a lightweight 16"

• Use the complete JP LMOS; BCG, Silent Captured Buffer and Adj GB

• the JP "Tank Brake" is the most effective brake on the market.

• ditch the boat anchor UBR and look into an Ace ARFX stock... it'll save you 2 lbs.

• Lancer makes a low profile carbon fiber tube. I'm pretty sure they make the length you're looking for. It'll save you a lot of weight and make your rifle look nice too.

• if you plan on using a scope, take a look at the MecharmorDefense "TacOps-1" charging handle.

If you hurry and order, you might be able to grab their special price still.

EasyEJL · August 28, 2014

I've thought about but where I hunt, I'll never be walking or stalking. I'll always be in a tree stand or box blind. And I like knowing that I have the capability I'd making those really long shots. Whether it be at an animal or having fun with a target.

are your really long shots going to be past 800 yards? because the difference up to 600-700 yards between a 16 and 20 is negligible, and performance deteriorates rapidly enough past that with either that you'd honestly be better off with a different round than 308 if its important to go that far.

TexA-R · August 28, 2014

What performance are you talking about? Does the performance gets worse with the longer barrel? I thought it improved. Weight is not an issue for me. I could care less how much it weighs. I'll never be shooting free hand or stalking. I've never shot past 300 but I would like to be able to shoot past 800 just for fun. I don't want to give up velocity and trajectory to save a few pounds.

Edited August 28, 2014 by TexA-R

EasyEJL · August 28, 2014

the group size performance. It does degrade faster with the 16", but the difference between the 16-20 isn't significant till past 800, and both still start to suck then. the dropoff is pretty rapid, just a little faster with the 16. Lets put it this way, I put a 20" on mine for the same reason, and i'm perpetually thinking about dumping it for a 16, or even a 14.5 with a pinned muzzle brake. I likely will never shoot past 500, and at that you can't tell the difference, in reality due to barrel whip the 20" could be worse than the 16". But that's a long story. Basically though if you take a heavy barrel 16" that weighs the same as a normal profile 20", the 16" is more accurate for at least that first 500 yards, probably still is close to 700.

TexA-R · August 28, 2014

I understand what you're saying. And it makes a lot of sense. I probably won't shoot over 400 or 500 except maybe a couple times. But the barrels I see shorter than 20. Are light contour. Is light okay? Or should I stick with med-heavy?

Robocop1051 · August 28, 2014

Heavy barrels were designed for machine guns. How many of your favorite deer rifles have bull barrels? The heavy barrels are for strings of fire, not for 1 to 3 shots at a buck. A light to med profile bbl will be near as accurate on a cold shot as a hvy to bull bbl.

Robocop1051 · August 28, 2014

A lightweight 16" bbl has the same stiffness as a 20" heavy barrel.

It's that whole concept of, "how many times can you break a stick in half?"

EasyEJL · August 28, 2014

a light 16 will still do better than a light 20 at 500 years. I saw guys doing videos of it using either a PSL or dragunov, can't remember now. Started with the standard I think its 24 1/2 inch barrel, and ran some rounds (7.62x54r), let it cool, sawed 2" off and shot some more. you could see the group tighten as the barrel shrank, I think their best group for that round with that barrel type was at 18, with 16 being close.

TexA-R · August 28, 2014

Who makes the best 16 inch barrels? And would an 18 inch even be worth it? I want it to be a little longer than 16. I don't like how short my .223 with a 16 barrel is.

Robocop1051 · August 28, 2014

Fulton Armory 18.5" barrel

NEMO 18.5" Barrel

And I think Mega has an 18 or 18.5 now too

edgecrusher · August 28, 2014

Who makes the best 16 inch barrels? And would an 18 inch even be worth it? I want it to be a little longer than 16. I don't like how short my .223 with a 16 barrel is.

You'd hate mine with a 7.5", lol

TexA-R · August 28, 2014

That's crazy. Is it just for fun? What's the purpose for going that short?

shibiwan · August 28, 2014

Being your first build, I think you're going overboard from a budget perspective. You've picked a lot of premium parts and from my personal experience, their costs don't add up when you consider the variability within you (yes, you) to shoot within 1 MOA consistently. You oughtta ask yourself, "how good is good enough" then plan around that.

Sorry man... just a reality check to think about. :)

BTW, low mass carrier on a 308? Uh it's not worth the weight savings to deal with the added recoil, especially if you're going with a carbine-length extension with the heavy UBR. Not sure where you really want to go with the build. So many contradicting requirements (e.g. heavy barrel, and lightweight parts).

Edited August 28, 2014 by shibiwan

TexA-R · August 28, 2014

I have no budget. Money is not an issue. And if it's my first build or my last, I'm going to use good parts. I want the gun to be the best it can be, that way if the shooting isn't good, Like you said, it could be me.

And the only reason I was looking at the jp bolt carriei is because I was planning on having a jp bolt and barrel. And I didn't want to deal with potential fitment issues mixing parts. I like the jp bolt carrier because of it's quality and reputation. If jp made a full mass carrier for .308, I would be all over it.

shibiwan · August 28, 2014

If you've got not budget but still worried about mixing parts etc, then have you considered purchasing a complete rifle like an LMT, LaRue or something similar from a premium custom manufacturer?

>:D

TexA-R · August 28, 2014

Yeah, I've looked at the LMT's they are very nice. I wouldn't mind having one in the future. But I've been itching to build something on the A-R platform. And now that I've been researching .308 builds, there's no way I'm not going to build it from the ground up. But I would definitely look into buying a completed one in the future. I just want to build one first.

98Z5V · August 28, 2014

^^^ Exactly. Call up LaRue, and see what they've got.

That PradatOBR would be one hell of a rifle for you.

warthog984 · August 28, 2014

It sounds like LaRue is caught up with demand now. I looked at the LMT 308 last fall at my local gun store. The one on the shelf was beat up. I asked to see one in the box. The sales clerk brought me another gun and it was the worse machining that I have ever seen on an upper receiver. LMT should have been ashamed to put that POS in a box. I have a LMT AR15 that I purchased 5 years ago and I would not compare the two.

D.R.D. · August 28, 2014

if money is no concern, order an 18" OBR

98Z5V · August 28, 2014

This bad boy right here has my nomination, if you want to stand up to the rigors of military-type abuse - it's strong enough, maybe even overkill:

http://www.laruetactical.com/predatobr-18inch

THIS ONE... The PredatAR. Personally, this would be as strong as the P-OBR, but the design is just incredible. I'd grab this one, and use the cost difference between it and the P-OBR towards optics:

http://www.laruetactical.com/18%E2%80%9D-larue-tactical-predatar-762

Full-on OBR, in 18" or 20" - doesn't get any better, tougher, etc., than that thing.

Edited August 28, 2014 by 98Z5V