Picking Parts For New Grendel Build

[JDub]

Greetings, Horde!!

I just received my AR-Stoner SS 18" Midweight 1:8 grendel mid-gas barrel. Although it was sold as a .265lbc barrel, it is indeed, as you all have stated, marked "6.5 Grendel 1-8". You boys must have some experience with these things!

I have a Bravo Co. stripped upper on hand and was going to mate the barrel to. Since my main goal is to shoot metallic silhouettes offhand, 1/2" MOA accuracy is not necessary but is surely welcomed. I was considering a MegaArms billeted or Vltor MUR because they are sexy (and more rigid) but do I really this when shooting from an unsupported position?

Now I just have to pick the rest of the parts. This is where you guys come in.

I have a list of what I've picked out. I would be honored to have your collective opinions to set me on my way to the enlightened grendel-building path.


Handguards/Forend:

YHM Smooth/Quad Float Tube

http://www.midwayusa.com/product/2696456874/yankee-hill-machine-free-float-tube-handguard-smooth-quad-rail-ar-15-aluminum-matte?cm_vc=mini_sell

Do I get mid-length or rifle-length?? I'd like to cover up the gas block but is that a bad idea for a first-time build?


Muzzle Device:

I was thinking A2 birdcage from AA just for simplicity and cost but I kinda like that WCI compensator. Thoughts?


Bolt Carrier & Charging Handle:

I was planning to use the bushmaster ones from my old A2 mid-90s vintage HBAR.


Lower:

Got a LMT with SOPMOD stock and LMT 2-stage trigger. Is the geissle SSA that much better than the LMT?


Gas Block:

YHM clamp-on style lo-pro. Woud I be better off with an adjustable one?

http://www.midwayusa.com/product/462151/yankee-hill-machine-gas-block-low-profile-clamp-on-ar-15-lr-308-standard-barrel-0750-inside-diameter-steel-matte?cm_cat=Cart&cm_pla=ProductDesc

Scope:

Leupold Vari-X III 8-25X50 with target knobs and AO. But I'd have to take that off my Savage 110FP and it's all sighted in. I wonder if this would be a decent alternative:

http://www.sightmark.com/products/riflescopes/85-25x50-triple-duty-riflescope-sm13011

I know it's a cheapy scope but I kinda want to see if it is decent. What could I lose for $160? I would be leaving it at 25X anyways.

That's about it. I'm stoked that this will be my first AR build and a Grendel to boot.

Anyhoo, thanks again to everyone for any and all feedback!

P.S. - Looks like I'm gonna cancel my AA 20" upper...I've got another 10 weeks to my delivery date and I just can't wait.

[kamrr4437]

For your handguard i would say its a matter of pure taste of what you like and what you will need. Even if you get a 4 railed handguard its not necessary to put everything in the kitchen sink, flashlight, laser etc. Be practical. But get what looks appealing and will work for you.

Muzzle device. Its really not needed the Grendel doesnt really have much recoil. A flashider would be fine. Will a muzzle brake help. Somewhat yes. But not really enough for me to warrant that little extra expense. But again its what works for the person shooting it.

Bolt carrier and charging handle. You can get a fine M-16 bolt carrier from Bravo company manufacturing which is chrome lined inside the bolt housing area and inside the gas key. You would want the M-16 bolt carrier because of the extra weight. You can buy other fancier ones which are chromed or Nickel Boron coated, etc but it basically just aids in cleaning it up easier IMHO. You can really get any charging handle that you want. Some people like the gas buster or the BCM gunfighter. Here again i think it depends on the persons taste. Its your gun make it like YOU want it and have a great time selecting parts.

Your lower should be fine. The trigger being 2 lbs sounds fine to me. Some people swear by Geissele. Here again i think it comes down to the person what feels right for you, how well can you operate the trigger accurately, etc. Mine is an Alexander Arms tactical trigger that basically has no take up and is adjusted to 2.75 lbs i tried it at 2 and it was to light so i moved it there. Im comfortable there. Its different for everyone.

Gas block i have had good luck with the troy low pro gas block. Some people like the adjustable gas block so they can fine tune it if they have any problems. Most guns that you buy dont come with that kind. Back to you handguard question if you get a low profile gas block you can get a rifle length or longer handguard and it will cover it up. Other than that you can get a mid length handguard and it will be visible in front of the handguard.

Scopes you will hear the expression buy once cry once. If your not going to shoot long range really i dont see a need in the huge magnified scope and the 50 mm objective but at least you would have it if you wanted to shoot some long range. Depending on your ranges that your going to shoot you can use a red dot, holographic, or scope it really depends on your intended use.

I dont have all the answers alot of others will give you great insight as the age range here spans from new and young to older and more experienced shooters. Great bunch of guys here. I will offer 2 more pieces of advice and one is that if you see something more expensive and dont have the funds at that moment but you want it, wait for it and get the better one. An ounce of prevention is worth a pound of cure and you will be happier in the long run. And 2nd but most importantly have a great time selecting parts and building your rifle. Welcome to the Horde!

Keith

[LRRPF52]

Since you have a mid-length gas system with a lot of dwell time, I would suggest getting an adjustable gas block. Since I prefer rifle-length handguards and recommend them, I would also suggest you cut a hole for your adjustable gas block. PRI makes a great low-profile block with a set screw adjustment at 90 degrees. All you need is a tiny hole that will allow the Allen wrench to fit through it directly to the set screw.

+1 for the M16 carrier. Since you do have the mid-length gas 18" barrel, I would only use the heavier carrier weight, rather than the shaved AR15 carrier from Bushampster.

The barrel, bolt, gas system, and recoil system should be the primary core of the rifle that you focus on, then work outwards. Reliability is the first goal, and as a home project, YOU are now the Total Quality Management program for your baby. There are many commonly overlooked components in this recipe, and some have already been identified by kamrr4437, such as the bolt carrier key and the Milspec requirement for them to be chrome-lined. Order one from BCM, and you will be GTG. I like to build mine myself as well, so that I can personally unitize the key to the carrier with high-strength, high-temp sealant, which is what Colt does, and a few others are just learning about.

Optics: For shooting off-hand, you'll want less scope magnification for shooting metallic silhouettes, and a lightweight scope with good glass at that. Don't ever spend $160 on a scope retail, you WILL be sorry. I don't take scopes seriously if they are meant for a high-power, centerfire rifle at under $300, and that would be a simple 1-4x scope or maybe a sale special on an economy tube with a good reputation.

A good 1-6x or 2-8x scope will be good for what you're doing. An 8-25x50 is a bit much for what you intend to do, especially on an 18" pipe AR15. It will feel and look ridiculous. Lightweight/compact/FOV will be your friend for this intended use.

[JDub]

Fellas, first off, thanks for the great suggestions. I hope I don't sound trite in saying that I really am grateful for the insights you've provided. I know you have saved me much time, money and frustration. Not to mention precious body parts.

The silhouettes I'm planning to shoot are NRA high-power silhouettes. Ya know, steel chicken(200m), pigs(300m), turkeys(375m) and rams(500m). I know I failed to make that clear. In that game, 20-25X is pretty normal 'cuz those bad boys don't move an inch.

Quick question: Does one need both an adjustable gas block and an M16 BCG? Would it not be possible to adjust the gas pressure down at the gas block so one wouldn't require the extra mass in the BCG to mitigate over-pressure. I am inexperienced in these things so I'm just trying to think it through.

[LRRPF52]

My BIL's FIL and his friend shoot those NRA steel sils all the time with .45-70 Sharps rifles, and even magnum pistols with optics off a bench. If you do need that much magnification, and want compact as well, you could look into March Optics, which have amazingly clear glass, and small scopes with crazy magnification factors. They are pricey, however. No free lunches with optics.

I would still suggest the M16 carrier, or weights added to your carrier if you're going to shoot the weight class of pills required to get solid hits on steel. You want the bolt to unlock slowly, and a gas block can't really affect that to the end that a heavy carrier and buffer can. The adj gas block really controls volume per space per time, and can be dialed down to tame your action.

I would also make sure the Bushmaster bolt carrier key is securely attached to the carrier. I have seen a lot of them come loose on guns that were run high-volume per range session/time. This was especially true in the early 2000's. My 90's-era 11.5" Bushy's ran 100% during 300-400rd range sessions, but I saw a lot of Mforgeries in 2003-2004 that should have never left the factory with the key attachment jobs they had. This is why I get a warm and fuzzy when I do my own. I also use a compression staking tool, rather than peening (and knocking loose) my carrier key after torquing the fasteners to 40 ft-lbs.

[JDub]

I'm not concerned with the form factor, so much, of the scope. I'd just prefer not to drop more than I paid for the rifle for it. When I bought the Leupold, it was <$600. Now they're over $900, yikes!

If I remember correctly, that Carrier Key is staked. I will obtain a M16 BCG...when I can find one in stock! Check on the the clamp-style lo-pro adjustable gas block. Can't find that in stock, either.

Is every man, woman and child in the continental U.S. building an AR at this very moment? It sure seems like it, sheesh!

[JDub]

Well things are falling into place. I received my tapco intrafuse armorer's wrench as well as a brass hammer today. Still waiting for the action block.

[grin&dull]

I went with a mid-length forearm and now wish I had gone with a rifle length to have a little more room for a bipod and sling mount. Unless you have an adjustable gas block chances are you’ll go a long time before you need access to it.
As far as the muzzle if you’re not going with a brake I’d go with just a thread protector and skip getting flash suppressor that is really kind of not needed for day to day use.

[JDub]

So I was looking for a workbench for my build because I've been using my computer desk as a workbench. I scored on this workbench from harbor freight:

http://www.harborfreight.com/60-inch-workbench-93454.html

It was $160 plus I used the 20% off coupon. $128, baby! It may seem cheap 'cuz it's from harbor freight but it is solid. Very sparse use of particleboard(and not in critical/load-bearing places). I was bracing myself to spend $300 plus for a workbench. It took about an hour to put together. Definitely would recommend to anyone.

[JDub]

Okay guys, I'm almost there. I've been looking high and low for a M-16 bolt carrier in stock and finally found one. It was a little pricey compared to the one from Bravo Co. but, as they say, "any port in the storm!"

http://primaryweapons.com/store/pc/viewPrd.asp?idproduct=253

It is a little heavier than the standard auto BC (9.9 oz. vs. 9.46 oz.) and it possesses only one gas port. I'll report back on it's performance once I've hit the range.

My current gas block is not adjustable (once again, the JP Enterprises clamp-on adjustable was out of stock everywhere I looked). I ended up buying a YHM clamp-on low-pro gas block. I became fixated on the clamp-on style because I have read here and elsewhere that the clamp-on style would yield better accuracy. I know I might be a little mis-guided...it's not like I shelled out for a high-end barrel but oh wellz.

I gouged the crap out of my YHM barrel nut because I had the action block on backwards (I'm an idiot, but the thing is not labelled and is not the type which protrudes up into the upper). But I'm gonna cut myself some slack because I'm a newbie...someone has to.

Hornady AMAX factory ammo and Leupold 1" qwr rings will arrive this week. Now I can mount my Vari-X III 8.5x25-40mm scope (again like an idiot I ordered 30mm rings before I realized the older Leupolds had 1" tubes). Hopefully within a couple of weeks I'll be off to the range. I wish it could be sooner but decent ranges in SoCal are neither abundant nor close and weekends are crazy busy during summer break...kids are in scouting, water polo and gymnastics.

Any advice on which dies to buy? Now that I have a decent workbench I've pulled my rock chucker out of mothballs. I even found some AA2520 in those boxes. I like it for .308. It was just as accurate as IMR4895 with 168gr. SMKs and metered way easier to boot. I also found some old rounds which were moly coated. My buddy said peeps don't really do that any more. Is that true?

Anyhoo, wish me luck!

[usmc1371]

sounds like you got a great start there. on my build i went with primary weapons muzzle brake. i reduced the muzzle climb for follow ups.http://primaryweapons.com/store/pc/v...6&idcategory=6

[LRRPF52]

That bolt carrier looks ideal for the Grendel, even more than an M16 carrier due to the weight, especially for your dwell time configuration of 18" pipe/MLGS. As long as the fasteners are secured, you should be GTG.

Bolt carriers are the main critical AR15 component that are in short supply right now, even with manufacturing ramped up like never before. This was also the case in 2009.

There are some great videos of AR15 assembly on youtube, especially from Brownell's, and other experienced builders. I prefer the clamshell type receiver jaws, rather than the inserts with pins, since I've seen an upper destroyed with the pin and insert system that literally tore off the lug for the pivot pin. I insulate the upper with plenty of thick 100mph tape, to prevent marring of the anodized finish, although it ony matters for aesthetics.

[BjornF16]

My current gas block is not adjustable (once again, the JP Enterprises clamp-on adjustable was out of stock everywhere I looked). I ended up buying a YHM clamp-on low-pro gas block.

Are you still looking for a JPE clamp on adjustable?...I have one with rail that I'm not using. http://www.jprifles.com/buy.php?item=JPGS-2B

[JDub]

Are you still looking for a JPE clamp on adjustable?...I have one with rail that I'm not using. http://www.jprifles.com/buy.php?item=JPGS-2B

Thanks for offering, Bjorn, but I have a rifle-length tube over my mid-length gas system so the gas block has to be low-profile.

Hopefully, with the heavier bolt carrier, I will not have problems cycling...we'll see when all the parts come in and I put 'er together.

[JDub]

I received my WCI comp from AA today. I was glad that they had those in stock and ready to ship.

Here's a pic of my build so far...click on the image for a large, full view.



What I have left:

1) Leupold 1" WQR High Rings - think I may need a riser to shoot offhand comfortably.
2) PWS Bolt Carrier.
3) Re-attach barrel with Loctite 243 per Bill Alexander's recommendation from this thread http://www.65grendel.com/forum/showt...=barrel+torque