thinking of building an AR

[justin22885]

im starting this thread to discuss and come up with ideas thatll go into a near future (start within the next 1-2 months) ar15 build and was wanting to discuss some of the options

i do want to go with an 80% lower, preferably an unmarked unfinished upper and lower.. at some point after i get my mill i will put my own logo on it so i'll just leave it all blank now

though i want to try different calibers, ill focus on 5.56 for the first upper assembly, either wanting to go with an M4 profile carbine, or a 20 inch rifle... since my goal is reliability i want to use a full auto style bolt carrier.. ive also heard of people pinning a metal or even a tungsten plug into the rear opening of the carrier to add mass, the idea is more mass = more momentum means itll overcome more friction and function more reliably... but the higher mass would require more gas and a stronger spring too

ill probably go with an M4 style upper with the M4 feed ramps whether i go for an M4 or rifle length barrel.. might have to swap the barrel extension on the rifle barrel to match the feed ramps

still looking for forearm options, but the barrel length i decide to go with would determine this.. id likely go with a magpul CTR stock

so what im looking to discuss is what barrel length i should go with, the forearm, parts selection for lowers/uppers, bolts, carriers, sights, gas block, etc so i know exactly which parts will go into it

its also been my opinion that piston kits were largely just gimmicks, but i may still consider a piston upper.. and depending on what the role of this rifle will be i will most likely be focusing on shooting M855, and handloads up to 75-80 grains so either 1-7 or 1-8 twist rate

if i go long barrel, im considering a DMR/LMG type rifle with a longer, heavier contour barrel and a bipod

any questions or suggestions?

 

[OpticsPlanet]

I know you are thinking about a long barrel, but have you ever considered a "pistol AR" with the Sig brace?

I have both a 20" AR15 (M16a1 clone) and a 16" M4gery and never considered a shorter barrel until I recently got the chance to shoulder one.

A "pistol" build with a 10.5" barrel and sig brace is one heck of a setup. The 10.5" barrel is enough unless you plan on shooting at longer ranges.

Check one out, I didnt see the appeal until I had it in hand.

Tim G.

 

[MachIVshooter]

i do want to go with an 80% lower, preferably an unmarked unfinished upper and lower.. at some point after i get my mill i will put my own logo on it so i'll just leave it all blank now

It's entirely doable, but will be time consuming, and there is a high probability of blemishes doing 80% lowers without a mill. Also a good chance of damage to a degree far more than blemished. Be sure to read/watch videos to have a good idea of what you're getting into.

It's also not at all cost effective if you have to buy a jig, unless you're going in on it with other people. Cheapest 80% forged 7075 lowers I'm aware of are $48, but the jigs are usually >$100. Meanwhile, finished lowers for $50-$80 are all over the place, and shipping/transfer fees shouldn't be more than $30-$40.

though i want to try different calibers, ill focus on 5.56 for the first upper assembly, either wanting to go with an M4 profile carbine, or a 20 inch rifle... since my goal is reliability i want to use a full auto style bolt carrier.. ive also heard of people pinning a metal or even a tungsten plug into the rear opening of the carrier to add mass, the idea is more mass = more momentum means itll overcome more friction and function more reliably... but the higher mass would require more gas and a stronger spring too

Don't go cobbling weight into the bolt carrier. If you feel that it's cycling too violently, get a heavier buffer (or put tungsten weights in the buffer).

ill probably go with an M4 style upper with the M4 feed ramps whether i go for an M4 or rifle length barrel.. might have to swap the barrel extension on the rifle barrel to match the feed ramps

Shouldn't have to unless you buy some old surplus barrel. I'm not aware of any being sold today that don't have M4 ramps, regardless of length.

still looking for forearm options, but the barrel length i decide to go with would determine this.. id likely go with a magpul CTR stock

The MOE handguards are my first pick for a cost effective upgrade, but if you can spend $100-$130, the UTG Pro super slim free float tube is pretty dang nice at a modest price. I went with the 15":

what im looking to discuss is what barrel length i should go with, the forearm, parts selection for lowers/uppers, bolts, carriers, sights, gas block, etc so i know exactly which parts will go into it

Depends on what you're wanting to do with it and what your budget is. I think a 16" middy is about the best general purpose configuration, and Magpul furniture is pretty tough to beat, but this is just an opinion. We need a little more info to narrow it down. The options are almost limitless, and the price range these days is huge. You can put together a pretty dang decent AR for $600-$700, but top shelf stuff is still gonna set you back a couple grand or more.

its also been my opinion that piston kits were largely just gimmicks, but i may still consider a piston upper.. and depending on what the role of this rifle will be i will most likely be focusing on shooting M855, and handloads up to 75-80 grains so either 1-7 or 1-8 twist rate

I wouldn't say gimmick, but more of a solution in search of a problem. The standard Stoner gas system (which is NOT direct impingement) works just fine, saves weight and usually costs less.

 

[LocoGringo]

Before ANY of this, DECIDE WHAT YOU WANT THE RIFLE/CARBINE FOR. I've come up with 5 distinctive uses. Usually, you can cover 2 of them pretty easily with 1 rifle, but 3 is virtually impossible. Once you decide on how you'll use it most (primary use) and a little (secondary use), features, characteristics and parts will fall into place.

The 5 uses I've come up with are (in no particular order):
1. Hunting
2. Long range/Precision
3. Tactical/Home Defense
4. Practical Competition (3-gun for example)
5. NRA high power competition

Decide among them which is your primary use and secondary use and you'll figure out the best way to build your rifle/carbine. There can be some carry-over for things like 3 and 4, but not for things like 3 and 5. Once you figure out how you're going to use it, build the tool around the use. I don't count "plinking" because you can do that with any setup.

 

[dprice3844444]

why would you want an 80% lower when you can buy a finished bushmaster lower for 50 bucks from brownells

 

[justin22885]

why build it myself?.. 80% lowers are typically unfinished and unbranded and as i stated in my original post i want to put my own logo on it.. also, i like doing stuff myself.. its why i built my AK as opposed to just buying an arsenal, this for me is as enjoyable as shooting them

at some point im probably going to get both, one thatll be an M4 length rifle and another one for more distance, power, and precision, where i live (wisconsin) its pretty flat and wide open here so im leaning towards having more range but the shorter stuff does seem to have more parts for them..

16 inches could be a good compromise.. the M27 IAR is essentially a mag-fed LMG based around the 416, if im not mistaken that has a 16 inch barrel too.. it would also offer more range and power over the shorter M4 size rifles and ill be running it through my tests to replace my AK in the role of my go-to rifle, AKs as you know are 16" as well

___

i can either go for a standard or a heavy barrel.. havent decided on this.. i will use the M4 feed ramps though because as i said my goal is the best effort for reliability, and the ability to go longer without regular maintenance

what else can i do in terms of reliability?.. more mass in the BCG, heavier springs, and more gas do a lot, but what else? last i was into ARs, piston uppers were only just starting to come out and they had major problems with things like carrier tilt and didnt seem to actually to make it more reliable.. seems like you could probably take it many more more rounds without cleaning before the ejector gums up and you have a failure to eject

what else could i do to extend the intervals between basic maintenance?

and ill check out the magpul stuff, i like their CTR stock so far

here are a couple images of rifles i like (ignore the scopes and the fact one is left handed)

http://jdub.supramania.com/Firearms/Noveske AR-15 SPR 01.jpg
http://sstacticalfirearms.com/wp-content/uploads/2013/01/Custom-AR2.jpg

 

[LocoGringo]

at some point im probably going to get both, one thatll be an M4 length rifle and another one for more distance, power, and precision, where i live (wisconsin) its pretty flat and wide open here so im leaning towards having more range but the shorter stuff does seem to have more parts for them..

16 inches could be a good compromise.. the M27 IAR is essentially a mag-fed LMG based around the 416, if im not mistaken that has a 16 inch barrel too.. it would also offer more range and power over the shorter M4 size rifles and ill be running it through my tests to replace my AK in the role of my go-to rifle, AKs as you know are 16" as well

___

i can either go for a standard or a heavy barrel.. havent decided on this.. i will use the M4 feed ramps though because as i said my goal is the best effort for reliability, and the ability to go longer without regular maintenance

what else can i do in terms of reliability?.. more mass in the BCG, heavier springs, and more gas do a lot, but what else? last i was into ARs, piston uppers were only just starting to come out and they had major problems with things like carrier tilt and didnt seem to actually to make it more reliable.. seems like you could probably take it many more more rounds without cleaning before the ejector gums up and you have a failure to eject

what else could i do to extend the intervals between basic maintenance?

and ill check out the magpul stuff, i like their CTR stock so far

here are a couple images of rifles i like (ignore the scopes and the fact one is left handed)

http://jdub.supramania.com/Firearms/Noveske AR-15 SPR 01.jpg
http://sstacticalfirearms.com/wp-content/uploads/2013/01/Custom-AR2.jpg

I think you might be a little confused. An M4 is a particular type of AR-15. It's a particular length and contour of barrel. Unless you plan on going for a NFA short-barreled rifle (less than 16" barrel), you can't REALLY do an M4 as, if I'm not mistaken, the real, military M4 barrel is 14.5" and unless you plan on pinning and welding a muzzle device to the end of it to make it permanently longer than 16", a M4 won't be possible. Most civilian ARs with M203 cutouts on the barrel are "M-4geries". M4 also refers to the contour under the handguard that you don't see. It's much lighter to carry, but less stiff for real accuracy. Don't forget to investigate gas system length and it's effect on recoil.

Like I recommended in my earlier post, decide on how you want to use the rifle/carbine first and the rest (parts, barrel length/contour, accessories, sighting system) will fall into place.

 

[MachIVshooter]

what else can i do in terms of reliability?.. more mass in the BCG, heavier springs, and more gas do a lot, but what else? last i was into ARs, piston uppers were only just starting to come out and they had major problems with things like carrier tilt and didnt seem to actually to make it more reliable.. seems like you could probably take it many more more rounds without cleaning before the ejector gums up and you have a failure to eject

I'd suggest simply running whatever upper you get before you decide to make it "more reliable". Some of us here have tried to see just how long our ARs with Stoner gas system will run without cleaning, just hosing the BCG with lube periodically. I finally got tired of blackened lube getting all over me just from handling it and cleaned my Armalite M15A2C after several thousand rounds; it still had not suffered a stoppage.

The lowest bidder aluminum GI magazines are the problem area, and the source of most of the complaints coming from the armed forces. Stick to Pmags or another high quality magazine and steer clear of Tula ammo or crappy reloads, you'll likely see 2,000+ MRBS in nearly any AR.

 

[Sam1911]

i can either go for a standard or a heavy barrel.. havent decided on this.. i will use the M4 feed ramps though because as i said my goal is the best effort for reliability, and the ability to go longer without regular maintenance

what else can i do in terms of reliability?.. more mass in the BCG, heavier springs, and more gas do a lot, but what else? last i was into ARs, piston uppers were only just starting to come out and they had major problems with things like carrier tilt and didnt seem to actually to make it more reliable.. seems like you could probably take it many more more rounds without cleaning before the ejector gums up and you have a failure to eject

what else could i do to extend the intervals between basic maintenance?

At this point, ARs are like Toyota Camrys. Good reliability record -- very dependable. You're kind of asking here, "So I'm planning to get a Camry. I figure I'll add a second battery and alternator, run-flat tires, replace the brakes with all stainless parts, switch to custom high end $15/qt. oils and lubes, have the engine torn down and blueprinted ... what else should I do so it is reliable?"

Most folks are going to say, it's ALREADY reliable. Far more reliable than you need to concern yourself over. What problem are you actually solving here, or are you just looking for a way to spend money?

And remember, the AR15/M16/M4 is an engineered, mature firearm design. Each part, each material spec, each spring rate, each mass is designed to work together. Trying to out-smart the designers (and decades of study by the armed forces, manufacturers, and many thousands of educated users) by throwing in heavier parts and heavier springs might be entertaining, but won't improve RELIABILITY. You're just as likely to throw off the balance and make reliability worse.

You might want to look up "Filthy 14." A plain jane BCM carbine used in classes that had had a documented 44,000 rounds through it a while back with only "extractor , 2 bolt lugs broke, so they replaced the BCG, and extractor spring 3 times." NO CLEANING! You could say that's reliable. (And that's not the only multiple-tens-of-thousands-of-rounds without cleaning gun they run!)

 

[justin22885]

im going to be piecing this rifle together and select each piece individually.. i'll be buying the 80% lower from ares because i want to support them financially i like the politcal stance they take.. i'll also need a plain A3 style upper, BCG, barrel, and furniture for the most part

i consider anything of 14.5 and below to be m4-length.. 16-18 to be mid length and 20" and above to be rifle length

let me keep it simpler by asking only one question at a time instead of a bunch at once.. in terms of bolt carriers i notice there are parkerized, but some are also nickle boron and chromed.. what advantages does a nickle boron carrier offer something like the BCM parkerized, chromed line carrier doesnt?

 

[carbine85]

You should decide on the barrel length 1st and go from there. I probably wouldn't mess with the 80% lower myself. There are too many cheap quailty lowers out there.
Here's a few thoughts:
1) The full auto carrier has nothing to do with reliabilty. Some guys use low mass carriers in 3 gun competition for quicker lock-up time.
2) M4 ramps aren't needed however most uppers and barrels will have them. They have no affect in a semi-auto application.
3) The M4 profile barrel won't serve any real purpose and a 1:8 twist is propably the best choice if you can find it.
4) MI Industries has some nice free float handguards at a reasonable price. I'm very pleased with mine.
5) Stock triggers should be replaced with a nice 2-stage trigger. It makes a lot of difference.

 

[Sam1911]

what advantages does a nickle boron carrier offer something like the BCM parkerized, chromed line carrier doesnt?

In theory it is a little easier to clean. In more extended theory, it might get along a little better without as much lube, though everyone pretty much runs ARs "wet" anyway.

 

[justin22885]

carbine 85, ill be using a 16" barrel, probably a more common contour, something that uses common .750" gas blocks, 556 chamber, primary ammunition will be M855 62 grain military surplus ammo, and handloads of this same bullet weight (my handloads will be designed to match the external ballistics of the M855 for consistency

since im looking to build this from the receiver up to be as reliable as possible, so i can run it through tests of my own along side similar tests with my 5.56mm AK (which will be getting an AR15 magwell conversion), then im interested in these nickle boron carriers, ill look into them more

are there any good aftermarket piston kits i should consider?.. id like to test the rifle with and without a piston to see if the piston offers any benefits that outweight the added weight of the rifle

i dont intend on running the thing dripping wet.. but a normal amount of lube on a regular basis, just not pouring out of the cracks dripping wet with oil

 

[Sam1911]

are there any good aftermarket piston kits i should consider?

I'd say no. There are several piston kits out there, but I wouldn't ever bother with one. After all, you said reliability is important to you. To me that means being able to grab the most common repair/replacement parts in the country from any number of vendors and expect they'll all work perfectly. Rather than having a proprietary aftermarket operating system available from one vendor, if that vendor stays in business and keeps supporting that design and your supply system (UPS/USPS, internet, etc.) stays solid enough that you can get stuff from them.

.. id like to test the rifle with and without a piston to see if the piston offers any benefits that outweight the added weight of the rifle

What benefits do you expect it COULD provide? What are you hoping to get out of this change? How would you discern that it was better or worse than the performance of the Stoner gas system?

 

[justin22885]

only benefit i could imagine is going longer without cleaning before something like the ejector gums up and causes a failure to extract.. but i do think direct impinged is best, i've already had the opinion that the piston adds more weight to the rifle, but also more parts that can break and when they do break, what can you fix them with?.. nothing

if a DI AR breaks what can you fix it with?.. first off all theres NOTHING to break in that system and if it did just about any AR or M4 will have the parts to fix that.. so i agree, direct impinged is best and probably wont even consider the piston stuff

im going to read up more on nickle boron and nitraded BCGs to consider if i should go for one of those or a parkerized/chrome lined carrier

im also going to go with a standard contour 16" barrel, not a heavy barrel or anything of the sort.. and for sights, im probably going to use a red dot more than anything else, so probably a set of magpul BUIS or HK style drum sights

i guess theres really not much more to say or ask except for brand names i guess.. i just need the BCG and an upper receiver at this point.. ill probably go through a few different grips and forearms till i find what i like

 

[justin22885]

here you go.. this is sort of what im gonig to go for

 

[goon]

One thing with the M-4 profile barrel is that it was made with that profile with the intention of being able to fit a grenade launcher in mind.

I don't have any plans to ever mount one of those on an AR.
So I'd prefer a profile without such theatrics... unless the M-4 profile is cheaper. In which case, I guess it'll do.

Personally, I really like a LW Midlength 16" barrel for handling and best compromise, but that's just me. The 16" does just a little better ballistically than a 14.5 w/ permanently mounted flash suppressor, but it's only an inch longer in the real world. The Midlength gas system is a little better balanced for that barrel length so moving parts should last longer with less wear. It has a little more sight radius (if you shoot with iron sights). I slightly prefer the Carbine 14.5" for handling, but when I think about money being spent, the Midlength keeps drawing me back.

But as long as you start with quality, you're pretty unlikely to have problems no matter what you go with.

One place I've found where you can really improve on the stock AR design is with a good trigger. I've been spoiled by the excellent trigger on my CZ-452. After that or one of the adjustable triggers that are standard on many hunting rifles these days, a stock AR trigger seems even more rough.

 

[Gordon]

16" barrel so you don't have to pin flash hider and get the velocity up a little more. Midlength gas tube as that works very well with the 16" length. Here is a good barrel, I'd go 1 in 7 as it shoots heavy bullets well and light ones OK. BCM stuff is as good as the non top tier (ie Noveske and La Rue ect. ) gets:
http://www.bravocompanyusa.com/BCM-...-WEIGHT-FLUTED-p/bcm-brl-mid-16-elw-f-std.htm

their blemed recievers are outstanding for under $100

 

[justin22885]

huh.. reading another thread on another forum someone mentioned the pistol with a brace... theoretically something like that with say a 10-12 inch barrel is legal?.. thats actually becoming a very attractive concept.. thing is where im at there are some very long distances.. would make that rifle very suitable for home defense though .. but im looking for a go-to rifle, not sure if something so short should be my "go to" rifle for a variety of situations, not just close quarters

but yeah.. the idea of being able to go with shorter barrels using that brace is interesting

 

[justin22885]

hmm, i just looked up the velocity differences between a 20 inch 1-7 barrel and a 12.5 inch 1-7 barrel.. only a dropoff of a tad over 200fps from 3100 in the 20 inch.. so theres really very little gains going anywhere higher than a 16 which has almost identical velocity to the 20.. guess m855 is designed to offer its best performance out of shorter lengths..

so without much of a drop off going from a 20 all the way down to a 12.5, and figure if you go with a 1-8 or 1-9 barrel where you can get optimum velocity with a 62 grain bullet, you could even make up some more of the velocity loss

so im going to do it, 12.5 inch 1-8 twist 5.56mm barrel, arm brace, black nitrided BCG, and a direct impinged gas system

 

[MachIVshooter]

hmm, i just looked up the velocity differences between a 20 inch 1-7 barrel and a 12.5 inch 1-7 barrel.. only a dropoff of a tad over 200fps from 3100 in the 20 inch.. so theres really very little gains going anywhere higher than a 16 which has almost identical velocity to the 20.. guess m855 is designed to offer its best performance out of shorter lengths..

so without much of a drop off going from a 20 all the way down to a 12.5, and figure if you go with a 1-8 or 1-9 barrel where you can get optimum velocity with a 62 grain bullet, you could even make up some more of the velocity loss

Most rifle rounds will gain or lose 25-30 FPS per inch of barrel, within a certain range from their ideal length. 5.56 ball ammo was designed around a 20" barrel. You'll see more dramatic drops below 10", and minimal gains beyond 24"-26".

Twist rate has no measurable effect on velocity. Go 1:7 or 1:8 to allow use of the heavier bullets, as 5.56, especially from a short barrel, will never get a bullet moving fast enough for a tight 1:7 twist to be problematic.

so im going to do it, 12.5 inch 1-8 twist 5.56mm barrel, arm brace, black nitrided BCG, and a direct impinged gas system

Good luck with that. As I told you earlier, the Stoner system is not DI.

 

[Sam1911]

Good luck with that. As I told you earlier, the Stoner system is not DI.

Probably fighting a losing battle there. Yes, not exactly a pure or classic DI system, but still one in which the gasses are directed and act in/on the bolt and carrier. The long and short of it is that Stoner's design is the closest thing to a DI system that 98% of gun folks know anything about, so it becomes a bit pointless to make much fuss over the differences, or to hold anyone's feet to the fire over a slight oversimplification of terms.

 

[goon]

Yep - you'd have to convince everyone on the internet to stop calling the AR system "direct impingement." Then you had to start making your way around to every local gun store in the US.

2.5 inch 1-8 twist 5.56mm barrel, arm brace, black nitrided BCG

If you think that will meet your needs. I have heard many good things about Palmetto State Armory, but their shipping is known to not be the fastest. Although now, with no one selling many guns, maybe their shipping will be faster. I think they have complete pistol lowers on sale right now for $129. They also frequently have "blemished" stripped lowers for $50, and I've seen Anderson stripped lowers elsewhere for $40.

 

[justin22885]

ill consider it.. but the more i think about it the more i want to go shorter.. something light, easy to carry for long periods of time.. i've been thinking of building an AKS-74U kit.. but i'll go for roughly the same size with this AR.. i will not go below 10.5 inches, ill check out palmetto though

 

[Browning]

In theory it is a little easier to clean. In more extended theory, it might get along a little better without as much lube, though everyone pretty much runs ARs "wet" anyway.

I can answer some of that as I bought a WMD NiB Bolt Carrier Group awhile back (7th of Jan 2013) to test. I bought it due to the claims of increased reliability, having to use no or little lube and that it was supposed to be easier to clean.

Okay, so fast forward to now a total rd count of 5,500 rds and 20 months later and reliability has been great, not one malfunction period in that entire time even when I shot it with no lube at all.

I ran it dry for quite awhile to see if it lived up to it's claims, it did but I still started to eventually apply lube (SLiP2000) as I didn't want shear off a lug or something.

Figured it would get dull eventually, but right now it's looking like a dirty S&W stainless revolver before it's cleaned rather than after the S&W SS revolver is cleaned.

After I'd already owned it for awhile and already used Hoppes #9 (which has ammonia in it) I was told that ammonia would eventually discolor it. Maybe it's due to that and maybe the discoloration is just due to wear.

After it arrived back then I took a few pics and compared it to a BCM BCG. Both are Full Auto BCG's with good staking

https://www.wmdguns.com/content.cfm

Back when it was new.




WMD and BCM BCG's shown side by side for comparison.







Now : Fast forward to right before I cleaned it a couple weeks ago (600 rds since last cleaning). At any rate as gleaming as it once was this is no longer the case.





This is right after cleaning including scraping the bolt, a 5 min soak in solvent, hitting it with a nylon brush and so on. So it's clean in this pic







It's about time to replace that rounded hammer though. That thing's had it.



At any rate the finish on the NiB BCG is still slick to the touch even when completely degreased, so that's the only thing that matters. Reliability has been flawless and I purposely don't clean it after every range trip. Been cleaning it between every 600 and 1,000 rds

I'd still buy one as part of an 'ultimate AR' package. I guess that says something.

Other drop-in AR parts for reliability.

http://www.defensereview.com/the-bi...pingement-gas-system-makes-the-m4-unreliable/

- heavier Sprinco buffer spring (correctly called an action spring).
- a DPMS Extra-heavy buffer (.2oz lighter than a Colt H3 buffer).
- a 5 coil extractor spring with a Crane O-ring for added extractor tension.

Those drop-in parts made my rifles obscenely reliable, and still do

BCM extractor upgrade kit (*Click*)